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April 08, 2005

Code of many colors

Can researchers see race in the genome? (Science News). Like many popular press articles the link (which is the first in a two part series, the second to be titled "The Race to Prescribe") is presented in the format of "the other side disagrees...." This is a shift, as the assumption is now that there are two valid sides. For the sake of argument, if the scientific consensus does start shifting toward the relevance of populational information presented as clusters ("race"), the expositors better get ready to beat back a resurgence of Platonic typologies. The fact is that the public does not usually engage in "population thinking" as biologists have been wont to do since the dominance of the Modern Synthesis even when it comes to the general fact of evolution. Remember, this is the public that credulously soaks up headlines shouting that "the gene has been discovered that causes-an-extremely-complex-polygenic trait-modified by many environmental factors" (fine print: "scientists note that gene X accounts for 15% of the variation in trait Y").

Related: Pattern Classification in Population Genetics, Pt. 1. Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies. Evidence for Gradients of Human Genetic Diversity Within and Among Continents.

Posted by razib at 10:57 PM | | TrackBack

Male Lactation

In comments to dobeln's post Tales From The Blank Slate - Part II Richard Sharpe writes:

Perhaps the next bold Swedish step is to require fathers to have hormone treatments so they can breast feed as well!

Now, I'm sure he thought he was being quite the quipster, but he provided me with just the right excuse to unleash this outlandishness.

Milkmen: Fathers Who Breastfeed

I first became interested in male lactation in 1978 after reading Dana Raphael's book, The Tender Gift: Breastfeeding. Although Raphael only dealt with the subject briefly, she did say that men can and have produced milk after stimulating their nipples.

[ . . . . . ]

We didn't give it much thought after that until years later when I came across a short article called "Male Lactation" by Professor Patty Stuart Macadam of the Department of Anthropology at the University of Toronto (Compleat Mother, Fall, 1996, Volume 43).

It is possible, and has been observed in animals and humans. In 1992, 18 Dayak fruit bats were captured from a rainforest in the Krau Game Reserve, Pahang, Malaysia. Of the 10 mature males captured, each had functional mammary glands from which small amounts of milk were expressed. A breast is a breast. Male lactation is physiologically possible and, according to Dr. Robert Greenblatt, production in males can be stimulated by letting a baby suckle for several weeks. Indeed some human males secrete milk at birth and at puberty.

Historically, male lactation was noted by the German explorer Alexander Freiherr von Humboldt prior to 1859, who wrote of a 32-year-old man who breastfed his child for five months. It was also observed in a 55-year-old Baltimore man who had been the wetnurse of the children of his mistress.

Here is the Wiki entry for Male Lactation. Here is an article from the gay parenting magazine And Baby. Here is the official statement from the National Association for Research and Therapy of Homsexuality. Here is Fiona Gile's book Fresh Milk: The Secret Life of Breasts in which she discusses male lactation. Here is our favorite author, Jared Diamond devoting over 20 pages (pages 41-62) to the topic of male lactation in his book, Why is Sex Fun?: The Evolution of Human Sexuality.

Diamond hits the topic again in Discover Magazine in his piece Father's Milk.

Experience may tell you that producing milk and nursing youngsters is a job for the female mammal, not the male. But your experience is probably limited, and the potential of biology--and medical technology--is vast.

Here is the story of a Sri Lankan widower who breastfeeds his children.

For those of you who appreciate historical precedent, there is David Livingstone's account of male lactation in Missionary Travels and Researches in South Africa. And if you're very selective in how you chose your Biblical interpretation, (or misinterpretation if you will) you can find passages such as:

Numbers:11-12: Have I conceived all this people? have I brought them forth, that thou shouldest say unto me, Carry them in thy bosom, as a nursing-father carrieth the sucking child, unto the land which thou swarest unto their fathers?

Isaiah:49-23: Kings shall be your nursing fathers, and their queens your nursing mothers: they shall bow down to you with their faces to the earth, and lick the dust of your feet; and you shall know that I am Yahweh; and those who wait for me shall not be disappointed

Here is a PubMed article, Lactation induced by luteotrophin in women with mammary cancer; growth of the breast of the human male following estrogenic treatment that notes the phenomena of male lactation.

Now, as Jane Galt noted in her outstanding essay on gay marriage there are usually unintended consequences that follow from initiatives that are advocated passionately in the politics of the moment. The region where the bizarre transforms into the everyday is not in the mainstream where people are contemplating the political issue rather the transformation occurs on the margin. We saw from the whole Summers fracas that the "gender is a social construction" mindset is quite alive and well. If feminism is predicated on an ideology that runs counter to biological constraints will it be biology or ideology that must give way? We see that the National Organization of Women has taken the American Society for Reproductive Medicine to task for having the gall to run advertisements advising women that:

"Advancing age decreases your ability to have children." The physicians viewed this as a public service, given the evidence of widespread confusion about the facts, but the group has come under fire for scaring women with an oversimplified message on a complex subject. "The implication is, 'I have to hurry up and have kids now or give up on ever having them,'" says Kim Gandy, president of the National Organization for Women. "And that is not true for the vast majority of women." Gandy, 48, had her first child at 39. "It was a choice on my part, but in most ways it really wasn't. It's not like you can create out of whole cloth a partner you want to have a family with and the economic and emotional circumstances that allow you to be a good parent. So to put pressure on young women to hurry up and have kids when they don't have those other factors in place really does a disservice to them and to their kids."

Clearly N.O.W. doesn't know how to reconcile biological limitations with the ideology that gender is a social construction. In my mind they are the likely candidate to be pushing on the margin for further research into artificial wombs: (also see our post on this topic)

Dr. Liu Hung-ching, a professor of obstetrics and gynecology at Cornell University in the United States, reported Tuesday at an international biotechnology conference in Taipei that she is currently working to develop an artificial uterus that would solve the problem of infertility for some women.

Combined with egg-banking:

Recent advances in banking frozen eggs have been spurred in part by the Catholic church's view that embryos must be protected as living individuals. In predominantly Catholic Italy, embryo freezing is frowned upon, and the practice was banned in February this year. Realizing the need for an alternative, Eleonora Porcu and her team at the University of Bologna have developed a liquid — including a sugar and 1,2-propanediol, which acts as an antifreeze — that allows eggs to survive freezing.

Using her solution, and fertilizing eggs by injecting sperm, Porcu has improved the success rate from one birth per 100 frozen eggs to about one in five3. "Egg freezing is almost ready to be introduced into the clinical routine," she concludes. Indeed, the Boston-based firm Extend Fertility already offers egg banking through their US fertility clinics for prices that start at $12,500.

And we may soon see a day where a woman, on a fundamental level, is really no different than a man. She would have some eggs extracted and frozen when she was in her twenties, then focus on her career and when the mood struck her she could phone the egg-bank and have her eggs unfrozen, impregnated with sperm and implanted into an artificial uterus.

Considering the lack of interest men are showing in higher education, and assuming that women can find some way to rewire their preferences so that they're content to marry down, the role of househusband should be one that has a bright future. Yes, ideology, with the aid of technology, will soon be able to trump biology.

And those househusbands, well they'll be at home nursing the baby, and to help you visualize such a future I leave you with pictures of man-boobs on prominent display.

Posted by TangoMan at 01:27 PM | | TrackBack

What's wrong with this picture?


Posted by scottm at 12:25 PM | | TrackBack

Question of the day

What makes a Firefly's tail glow?

(I'm pretty sure Razib knows the answer, so I'll ask him to sit this one out)

UPDATE OK That one was easy and AG got it in the comments, so I'll ask a second question: why is complete COX-2 inhibition not a good thing? (COX-2 is the protein implicated in colon, breast and prostate cancer for which drugs such as Vioxx inhibit)

Posted by scottm at 10:51 AM | | TrackBack

Tales from the blank slate - Part II

Striking another body blow against Discrimination, the Swedish government has now decided to ban all gender-based differential pricing. Women will have to pay full price for a number of services, such as Taxi rides, and will no longer be let into nightclubs at earlier ages than males.

Males will on the other hand no longer be able to enjoy cut-rate haircuts. Take that patriarchy!

This bold initiative comes shortly after the latest government equality push, aimed at making it harder for women to stay at home with their children. (Essentially, unless you split parental leave 50-50, you will be punished financially)

TangoMan Adds: Let's not overlook the recent turn of events in Norway where the government will dissolve a company that doesn't have women comprising 40% of its Board of Directors.

Posted by dobeln at 03:07 AM | | TrackBack

April 07, 2005

Dancing Air Force Cadet Makes Country Proud

It makes me proud to realize that we celebrate diversity in all its forms at the U.S. Air Force Academy and that this Dancin' White Boy (caught on tape by his roommate) does have the rythym to put his aircraft through precisely timed maneuvers. Besides which, who wouldn't look up to an officer who's got the moves like this guy.

(Via Andrew Sullivan)

Posted by TangoMan at 03:37 PM | | TrackBack

April 06, 2005

The Comparative Advantage of the US

In the comments section to Arcane's post on Humans, Neanderthals, and Free Trade there is a debate focused on comparative advantage and free trade. I thought it would be helpful to inject some actual data into the mix so I pulled up this 15% finished post (basically just working data) that I just lost interest in finishing (I've got a lot of these types of posts cluttering up my computer) and thought I'd offer it here, with a "No-Satisfaction Guarantee" sticker slapped on it. Here's some raw data on US trade practices with no conclusions attached. Make of the data what you will.

Enjoy or ignore.

US Comparative Advantages


In 2002, the US exported $682 Billion in products and $292 Billion in services. In the same year it imported $1,165 Billion in products and $227 Billion in services. Source.

Breaking down the EXPORT in services we find that Travel accounted for $66.5 Billion, Passenger Fares for $17 Billion, Other Transportation for $29.2 Billion, Royalties & License Fees for $44.1 Billion, Other Private Services for $122.6 Billion, Transfer Under US Military Sales Contracts for $11.9 Billion, and US GOv't Misc. Services for $0.8 Billion. Source.

Breaking down the IMPORT in services we find that Travel accounted for $58 Billion, Passenger Fares for $20 Billion, Other Transportation for $38.5 Billion, Royalties & License Fees for $19.3 Billion, Other Private Services for $69.4 Billion, Direct Defense Expenditures for $19.2 Billion, and US GOv't Misc. Services for $2.9 Billion. Source.

Our $65 Billion trade surplus in services is accounted for by two categories: license fees and other private services.

In Advanced Technology the US is running a deficit of $24 Billion for the first 11 months of 2003. Source.

A trade deficit of $114 Billion with China for the first 11 months of 2003.Source.

A trade deficit of $46 Billion with the OPEC countries for first 11 months of 2003.Source.

A trade deficit of $37 Billion with Mexico for the first 11 months of 2003.Source.

Here are the top 10 Countries with which the US has a trade deficit on November 2003 and the year-to-date deficit amounts to $387.6 Billion.Source.

Here are the top 10 Countries with which the US has a trade surplus on November 2003 and the year-to-date surplus amounts to $29.9 Billion. Source.

Here are the top 10 trade partners of the US and the total value of both imports and exports. Source.

A trade deficit of $7.6 Billion with India for the first 11 months of 2003. Source.

A trade deficit of $488.4 Billion with the World for the first 11 months of 2003. Source.

SIC Trade Figures.

Trade Surplus over a billion dollars in these SIC categories: 098,122,211,251,282,533,574,582,597,728,972

Trade Surplus over two billion dollars in these SIC categories: 012,041,044,081,263,511,575,598,723

Trade Surplus over five billion dollars in these SIC categories: 222,714,874

Trade Surplus over twenty billion dollars in these SIC categories: 776,792

Total Product Exports = $661 Billion. Total Product Imports = $1,150 Billion.

There are 263 classifications. The US has a positive trade balance to the world in only 99 of them.

Below are the SITC categories in which the US maintains a trade surplus:

011 Meat Of Bovine Animals, Fresh, Chilled Or Frozen
012 Meat, Other Than Of Bovine Animals, And Edible Offal, Fresh, Chilled Or Frozen (except Meat And Meat Offal Not Suitable For Human Consumption)
017 Meat And Edible Meat Offal, Prepared Or Preserved N.e.s.
022 Milk And Cream And Milk Products Other Than Butter Or Cheese
025 Birds' Eggs And Egg Yolks, Fresh, Dried Or Otherwise Preserved, Sweetened Or Not; Egg Albumin
041 Wheat (including Spelt) And Meslin, Unmilled
042 Rice
043 Barley, Unmilled
044 Maize (not Including Sweet Corn) Unmilled
045 Cereals, Unmilled (other Than Wheat, Rice, Barley And Maize)
046 Meal And Flour Of Wheat And Flour Of Meslin
047 Cereal Meals And Flours, N.e.s.
057 Fruit And Nuts (not Including Oil Nuts), Fresh Or Dried
081 Feeding Stuff For Animals (not Including Unmilled Cereals)
091 Margarine And Shortening
098 Edible Products And Preparations, N.e.s.
121 Tobacco, Unmanufactured; Tobacco Refuse
122 Tobacco, Manufactured (whether Or Not Containing Tobacco Substitutes)
211 Hides And Skins (except Furskins), Raw
212 Furskins, Raw (including Furskin Heads, Tails And Other Pieces Or Cuttings, Suitable For Furriers' Use)
222 Oil Seeds And Oleaginous Fruits Used For The Extraction Of Soft Fixed Vegetable Oils (excluding Flours And Meals)
223 Oil Seeds And Oleaginous Fruits, Whole Or Broken, Of A Kind Used For Extracting Other Fixed Vegetalbe Oils (including Their Flours And Meals, N.e.s.)
232 Synthetic Rubber; Reclaimed Rubber; Waste, Pairings And Scrap Of Unhardened Rubber
244 Cork, Natural, Raw And Waste (including Natural Cork In Blocks Or Sheets)
246 Wood In Chips Or Particles And Wood Waste
247 Wood In The Rough Or Roughly Squared
251 Pulp And Waste Paper
261 Silk Textile Fibers
263 Cotton Textile Fibers
264 Jute And Other Textile Bast Fibers, N.e.s., Raw Or Processed But Not Spun; Tow And Waste Of These Fibres (including Yarn Waste And Garnetted Stock)
266 Synthetic Fibers Suitable For Spinning
269 Worn Clothing And Other Worn Textile Articles; Rags
273 Stone, Sand And Gravel
278 Crude Minerals, N.e.s.
282 Ferrous Waste And Scrap; Remelting Ingots Of Iron Or Steel
283 Copper Ores And Concentrates; Copper Mattes; Cement Copper
284 Nickel Ores And Concentrates; Nickel Mattes, Nickel Oxide Sinters And Other Intermediate Products Of Nickel Metallurgy
287 Ores And Concentrates Of Base Metals, N.e.s.
288 Nonferrous Base Metal Waste And Scrap, N.e.s.
289 Ores And Concentrates Of Precious Metals; Waste, Scrap And Sweepings Of Precious Metals (other Than Gold)
291 Crude Animal Materials, N.e.s.
321 Coal, Pulverized Or Not, But Not Agglomerated
335 Residual Petroleum Products, N.e.s. And Related Materials
345 Coal Gas, Water Gas, Producer Gas And Similar Gases, Other Than Petroleum Gases And Other Gaseous Hydrocarbons
411 Animal Oils And Fats
421 Fixed Vegetable Fats And Oils, Soft, Crude, Refined Or Fractionated
431 Animal Or Vegetable Fats And Oils Processed; Waxes And Inedible Mixtures Or Preparations Of Animal Or Vegetable Fats Or Oils, N.e.s.
511 Hydrocarbons, N.e.s. And Their Halogenated, Sulfonated, Nitrated Or Nitrosated Derivatives
512 Alcohols, Phenols, Phenol-alcohols And Their Halogenated, Sulfonated, Nitrated Or Nitrosated Derivatives
513 Carboxylic Acids And Anhydrides, Halides, Peroxides And Peroxyacids; Their Halogenated, Sulfonated, Nitrated Or Nitrosated Derivatives
514 Nitrogen-function Compounds
516 Organic Chemicals, N.e.s.
523 Metallic Salts And Peroxysalts Of Inorganic Acids
524 Inorganic Chemicals, N.e.s.; Organic And Inorganic Compounds Of Precious Metals
533 Pigments, Paints, Varnishes And Related Materials
541 Medicinal And Pharmaceutical Products, Other Than Medicaments (of Group 542)
553 Perfumery, Cosmetics, Or Toilet Preparations, Excluding Soaps
554 Soap, Cleansing And Polishing Preparations
562 Fertilizers (exports Include Group 272; Imports Exclude Group 272)
571 Polymers Of Ethylene, In Primary Forms
572 Polymers Of Styrene, In Primary Forms
573 Polymers Of Vinyl Chloride Or Other Halogenated Olefins, In Primary Forms
574 Polyacetals, Other Polyethers And Epoxide Resins, In Primary Forms; Polycarbonates, Alkyd Resins And Other Polyesters, In Primary Forms
575 Plastics, N.e.s., In Primary Forms
579 Waste, Parings And Scrap, Of Plastics
581 Tubes, Pipes And Hoses Of Plastics
582 Plates, Sheets, Film, Foil And Strip Of Plastics
591 Insecticides, Fungicides, Herbicides, Plant Growth Regulators, Etc., Disinfectants And Similar Products, Put Up Or Packed For Retail Sale, Etc.
592 Starches, Inulin And Wheat Gluten; Albuminoidal Substances; Glues
593 Explosives And Pyrotechnic Products
597 Prepared Additives For Mineral Oils Etc.; Liquids For Hydraulic Transmissions; Antifreezes And Deicing Fluids; Lubricating Preparations
598 Miscellaneous Chemical Products, N.e.s.
611 Leather
621 Materials Of Rubber, Including Pastes, Plates, Sheets, Rods, Thread, Tubes, Etc.
642 Paper And Paperboard, Cut To Size Or Shape, And Articles Of Paper Or Paperboard
653 Woven Fabrics Of Manmade Textile Materials (not Including Narrow Or Special Fabrics)
655 Knitted Or Crocheted Fabrics (including Tubular Knit Fabrics, N.e.s., Pile Fabrics And Open-work Fabrics), N.e.s.
656 Tulles, Lace, Embroidery, Ribbons, Trimmings And Other Small Wares
657 Special Yarns, Special Textile Fabrics And Related Products
664 Glass
673 Iron Or Nonalloy Steel Flat-rolled Products, Not Clad, Plated Or Coated
711 Steam Or Other Vapor Generating Boilers, Super-heated Water Boilers And Auxiliary Plant For Use Therewith; And Parts Thereof
714 Engines And Motors, Nonelectric (other Than Steam Turbines, Internal Combustion Piston Engines And Power Generating Machinery); Parts Thereof, N.e.s.
721 Agricultural Machinery (excluding Tractors) And Parts Thereof
723 Civil Engineering And Contractors' Plant And Equipment
728 Machinery And Equipment Specialized For Particular Industries, And Parts Thereof, N.e.s.
735 Parts And Accessories Suitable For Use Solely Or Principally With Metal Working Machine Tools, Whether Or Not Removing Metal; Hand Held Tool Holders
741 Heating And Cooling Equipment And Parts Thereof, N.e.s.
742 Pumps For Liquids, Whether Or Not Fitted With A Measuring Device; Liquid Elevators; Parts For Such Pumps And Liquid Elevators
774 Electro-diagnostic Apparatus For Medical, Surgical, Dental Or Veterinary Sciences And Radiological Apparatus
776 Thermionic, Cold Cathode Or Photocathode Valves And Tubes; Diodes, Transistors And Similar Semiconductor Devices; Integrated Circuits, Etc.; Parts
786 Trailers And Semi-trailers; Other Vehicles, Not Mechanically Propelled; Specially Designed And Equipped Transport Containers
791 Railway Vehicles (including Hovertrains) And Associated Equipment
792 Aircraft And Associated Equipment; Spacecraft (including Satellites) And Spacecraft Launch Vehicles; And Parts Thereof
871 Optical Instruments And Apparatus, N.e.s.
872 Instruments And Appliances, N.e.s., For Medical, Surgical, Dental Or Veterinary Purposes
874 Measuring, Checking, Analysing And Controlling Instruments And Apparatus, N.e.s.
882 Photographic And Cinematographic Supplies
891 Arms And Ammunition
892 Printed Matter

Here are all the SITC codes.

The private good producing industries in the US accounted for 21.6% of the GDP in 2001.
Agriculture = 1.4%
Mining = 1.4%
Construction = 4.8%
Manufacturing = 14.1%

The private service producing industries in the US accounted for 66.8% of the GDP in 2001.
Transportation & Utilities = 8.1%
Wholesale Trade = 6.8%
Retail Trade = 9.2%
Finance, Insurance & Real Estate = 20.6%
Services = 22.1%

The Governments in the US accounted for 12.7% of the GDP in 2001.
Federal = 3.9%
State & Local = 8.8%

In 2001, 58.3% of GDP was directed at employee compensation. For agriculture compensation amounted to 40.9% and for mining 28.5%.

Construction compensation was at 65.2%, while manufacturing compensation accounted for 66%.

Transportation & utilities amounted to 46.6%, with wholesale trade compensation accounting for 55.8%, retail trade at 57%, Finance, Insurance & Real Estate at 25.6% and services compensation at 73.9%. Government compensation comes in at 82.9%


Here is the GDP by Industry, as measured in dollars.

Data on world trade in services

Posted by TangoMan at 03:11 PM | | TrackBack

Update 2

From time to time I look through my old posts to see if any of them are still worth reading.

I gave a guide to the earliest ones here and an update in October 2004 here.

I think the following posts since October may still be of interest:

Dawkins on Kin Selection summarises and comments on Richard Dawkins’s often-cited but seldom-read paper ‘12 misunderstandings of kin selection’.

Continuing the theme of kin selection, It’s a Ring Thing explores how to measure coefficients of relationship in cases where the parties are related and/or inbred, using Wagner’s Siegfried and Brünnhilde as an illustration.

Limits to Hamilton’s Rule warns that W. D. Hamilton’s theory of inclusive fitness is seldom useful unless the organisms concerned are very closely related.

The X Chromosome Waltz explores exactly what is meant by saying that an X chromosome spends twice as long in female bodies as in male ones. (A note in that post proved that the limit of the sum 1/2 + 2/4 + 3/8 + 4/16 + 5/32.…. is 2. It was pointed out in comments that there is a simpler proof using elementary calculus.) A related post, X Chromosome Evolution, analyses the evolution of genes on an X chromosome which increase fitness when they occur in one sex while reducing fitness in the other, which has been suggested as a possible cause of homosexuality.

A cluster of posts earlier this year examined Frank Salter’s theory of ethnic genetic interests. Interracial marriage: Salter’s Fallacy identified what in my view is a fallacious argument Salter uses against interracial marriage. Ethnic Genetic Interests is a more general criticism of Salter’s theories. I emphasise that Salter himself does not put his theories forward as a scientific explanation of behaviour, but as a political proposal for how people should behave if they wish to recognise their ’ethnic genetic interests’. I do not see any reason why they should. A further post, Ethnic Genetic Interests: Part 2, contains some more technical criticisms.

As I have often been sceptical about group selection, I felt honour-bound to describe an apparently neglected paper I had found, which sets out a model in which group selection can work, though in a fairly narrow range of circumstances. I did this in a post Group Selection can work…just.

British or English? discusses the rather confusing issues of national identity and nomenclature within the British Isles. I subsequently (here) corrected the statement that ‘about half of the population of Wales speak Welsh‘, as it was pointed out in comments that this was too high.

More recently there is a cluster of posts on various aspects of ethnic groups in Britain: here on crime; here, here and here on education; and here on inter-ethnic marriage. Not much theory, but plenty of facts and figures, for those who like that kind of thing.

Posted by David B at 01:57 AM | | TrackBack

April 05, 2005

What people should know about evolution

As a follow up to Why evolution doesn't make sense, below I offer two examples where a deeper understanding of evolution might be useful.

A few months ago there was a fear over avian bird flu spreading to humans. Wendy Orent, author of Plague, was making the talk show rounds trying to calm everyone down. Her reasoning was plainly Darwinian: an extremely virulent pathogen like the avian bird flu could only flourish in the artificially dense concentrations of chickens in East Asia. Since humans live at a much lower density such a virus would not spread easily as the carriers would die before they could pass the pathogen on to someone else. Plain ho hum Darwinian logic.

Another example is the "human universal" where female infidelity is never treated more lightly than male infidelity, and in fact, there is a tendency for female infidelity to be a far greater social transgression. There are many higher order explanations one could offer, from the controlling arm of the patriarchy to the need for family property to be passed down through the bloodline. But there is a standard Darwinian explanation: those males who were not jealous did not reproduce their genes or values nearly to the same extent as those who were jealous. Motherhood is certain, fatherhood is theoretical (though to a high degree of confidence). Please note that the method of transmission could be cultural.

The moral of the story is that evolution sits atop the engine of replication. Genes/individuals who replicate are successful. The proximate observed diversity of life is due to the scramble to replicate by developing adaptations which maintain the vessel of transmission, the body, long enough for the genes make another copy to recapitulate the process. A focus on macroevolution, with its tendency to highlight morphological change, neglects the reality that the ultimate reason behind this change is the race to replicate. Pathogens do not exhibit gross morphology to the human eye so they are not the exemplars of evolution in the public imagination, but they are superior replicators whose traits are of immense significance to human beings.1

Replication's centrality to evolution should be no great news, The Selfish Gene was written over 25 years ago, and a gene/individual level of selection is the dominant orthodoxy in evolutionary biology. But this is a case where public appreciation is at variance with the established consensus in the field, the diversity of life in all its morphological glory and detail have received more press in the past generation, exemplified by the success of the late Stephen Jay Gould's popularization's of Natural History. One could say that humans have a "sensory bias" toward focusing on vivid morphological diversity rather than the universal algorithm which brings it into being, but this emphasis on the particular over the general tends to result in an inability to extrapolate evolutionary principles to a wider range of circumstances. Ah, the love of butterfly collections....

1 - They kill us, they digest our cellulose, and, they might be responsible for sex.

Posted by razib at 06:27 PM | | TrackBack

April 04, 2005

Dissolving the dominance of dominance

Over the past few years one problem I have had when discussing issues of genetics with people are confusions issuing out of high school recollections of the dominant-recessive concept. Because this concept is introduced rather early on and emphasized through the ubiquitous Punnet Square there is often confusion about how polygenic additive traits can exist in light of the perceived centrality of dominance and recessive. Nearly a century ago R.A. Fisher theoretically reconciled (PDF) polygenic continuous variation (quantitative genetics) with a Mendelian paradigm, but obviously most people aren't going to be reading decades old population genetics papers, and I am not sure that such a mathematical exposition is easily internalized by most.

Recently I stumbled on to this philosophical diatribe against the concept of dominance in biology. The author basically seems to suggest that we should ditch the emphasis that we place on dominance and recessive and start from first principles and focus on the idea that in diploid organisms two copies of a given gene are expressed on any locus. To me this argument is made particularly powerful by the molecular revolution, for now we can illustrate how dominance might actually work in the context of the Central Dogma and a few basic concepts that are already partially digested from the cultural zeitgeist.

Consider that you have an organism which processes nutrient X via enzyme z. Enzyme z is synthesized like so:

Gene z - > transcription of mRNA -> translation of mRNA -> Enzyme z

Now, imagine that there is a "null" copy of Gene z, a mutation on the promoter prevents the initiation of transcription. In this case null-Gene-z results in lack of production of enzyme z, ergo, the inability to process nutrient X.

But in diploid organisms you have two copies of a gene. If you have a normal copy and a null copy there will be production of the enzyme, but only half the normal amount of enzyme will be generated because only half the normal amount of DNA is transcribed.1 If 1/2 of the normal concentration of enzyme is sufficient to break down enough of nutrient X so that the organism seems healthy one might say that the trait is "dominant," but at the molecular level the heterozygote is expressing only "half" the phenotype as a pure "wild type."

It might be that in a normal context there is almost never enough of nutrient X in the environment so that more than 50% of the enzyme z is necessary for optimal functioning (the abundance of nutrient X is the limiting factor). But there could be rare circumstances where nutrient X is very abundant and those organisms who have both copies of the functioning gene can take advantage of their enzymatic advantage and store the end product of nutrient X for future use when there is a deficit. In this case there is a clear fitness advantage that wild type homozygotes have over heterozygotes, but it is not normally observed over short time scales. Additionally, there is the possibility that gene z is prone to mutation in the somatic (body) cells that process nutrient X, so those individuals with some level of redunancy might have a long term life history advantage over heterozygotes who might harbor a multitude of sub-optimal cells which fail to process nutrient X by the end of their life because they have no "back up" plan.

In any case, I think that this narrative does have conceptual advantages over the dominance-recessive idea, and is simple enough that it can be introduced at the secondary educational level. As the author of the paper above notes it would also render terms like "codominance," "incomplete dominance," "penetrance," etc. redundant. And the idea of starting at the molecular level might also make an understanding of polygenic traits a bit more comprehensible, and in the future polygenic traits are going to loom large in the public imagination as the low hanging single locus fruit are picked clean and scientific press releases begin to skew toward more complex phenotypes.

1 - This is simplistic, there are a lot of issues relating to how/why/to what extent genes get expressed. One could perhaps concoct a model where the organism up regulates gene expression by producing a factor which induces more frequent binding of the polymerase when it "detects" that nutrient X is not being metabolized efficiently. We'll neglect such counter scenarios.

Posted by razib at 08:57 PM | | TrackBack

The human brain evolution revolution

Over at PLOS Biology, an excellent survey titled "Molecular Insights into Human Brain Evolution."

Related: Molecular Evolution of the Human Brain and Gene controlling brain size

Posted by razib at 10:33 AM | | TrackBack

April 03, 2005

Why evolution doesn't make sense

When I was in high school I did a project with a girl who was the younger sister of a girl I knew. Our topic was dinosaur biomechanics, and I remember spending some time trying to find information on the Diplodocus stride in those pre-web days. One afternoon my partner said me, "Evolution makes no sense, we don't see anything evolving...." I ignored her and continued, for as you might know where I went to school such was the orthodoxy. My partner was not from a fundamentalist household and was no Creationist footsoldier, evolution just "didn't make sense" to her.

When I was in 7th grade I had to take a test to place in the "gifted" track. The was an in depth interview with a psychologist for the school district. There were the standard looking at shapes, solving geometrical problems, but there was also a battery of questions related to general knowledge topics. At one point the psychologist asked me what "Charles Darwin's theory" was about, and I gave a cookie cutter answer about common descent and selection of the "fittest" and what not. The interviewer told me that he had never received such an accurate and precise response on that particular question. I was shocked and frankly disturbed, as I had been exploring evolutionary concepts since I was about 8 years old, and never considered them anything but banal background facts that framed my universe.

Such is not the case for all, and, it might be possible that it will never be the case for most, and I think the answer itself is ironically our evolutionary history and the imprint it has had on our minds.

To elaborate, consider the idea that evolution is not happening because we don't observe it in our own lifetimes. One thing that I realized is that there is a hint of Lamarckism in that viewpoint, that is, that there is continuous relationship between ontogeny and evolution, that we are evolving in our own lifetimes. This is not the standard Darwinian paradigm at all, though Darwin left room for acquired characteristics in his model the Modern Synthesis of evolutionary theory is clearly one which emphasizes that it is selection from a genetically and phenotypically varied population that is the prime force behind morphological change. The fact that this insight is not clear to those who are not ideologically biased against evolution a priori because of religious or political commitments suggests to me that there is something profoundly "unnatural" about evolutionary theory as it is today when viewed in the context of our minds.

Consider the time scales that evolution operates over. I have just noted above that evolution operates on the scale of generations, individuals within a population have differential fitness correlated with different phenotypes. We will not therefore see evolution occurring before our eyes among creatures with long generations, including humans.

Assume that a human generation is 20 years. That is ten generations over 200 years, the normal limits of verbal/oral memory held through a family. There are 100 generations over 2,000 years, a span of time that usually exceeds the lifespans of national, political and religious entities! There are 1,000 generations in 20,000 years. There are 2,000 generations in 40,000 years, roughly the period of time when H. sapiens sapiens has been the sole hominid on this planet. The common ancestry of H. sapiens neandertalis and H. sapiens sapiens probably extends back about 200,000 years toward various populations of H. heidelbergensis in Western Eurasia. That's 10,000 generations back to our common ancestry with our sister subspecies!

Humans have an innate numeracy, but its discrete and precise range is not much farther than 6 or 8. Beyond that point we live in an analog world or must dig into the realm of abstract mathematics. The last common ancestor between our own species and another homonid lineage might be pushed back on the order of millions of years, that is, tens and perhaps hundreds of thousands of generations back into the past. Unless you are a Methuselah or a god such timescales simply exist outside of the realm of "common" sense and plain conception.

Of course "microevolution" continues, selection on traits within a species, which has resulted in the stocky build of the Inuit peoples in the last 15,000 years, less than a 1,000 generations, or the rise of tall and lanky Nilotic herders with animal domestication on the bright plains of East Africa, perhaps as few as serveral hundred generations. But this is not the "evolution" that many in the public imagine, and Creationists admit to microevolution as within the realm of possibility. The public aims for speciation, and in particular a morphological shift, a reorganization, to grab one's attention and attest to the sweeping salience of mutational induced change in one's lifetime.

This is simply problematic as it is predicated on a "hopeful monster" thesis promoted by the likes of Richard Goldschmidt but repudiated for over two generations. Rather, the promoters of the Modern Synthesis emphasize more gradualistic change, and assert that macroevolution and microevolution are ontologically ultimately the same. Even those who dissent from the orthodoxy, like the late Stephen Jay Gould and Niles Eldridge, rejected the saltationalist idea of hopeful monsters rooted in the possibility of widescale one-generational genetic reorganization. Part of the issue is the public perception that mutation is more important to evolutionary change than selection, when mutation is simply a background given that is shaped by the algorithmic logic of natural selection.

Certainly change can happen in a few generations. Consider the empirical equation for selection response on a trait (used for artificial breeding):

R = h2*S

h2 = realized heritability & S = selection differential of breeding and parental population (breeding as in the subset of the population chosen to sire the next generation).

If you had a population of humans whose mean height was 60 inches, 5 feet, how long would it take their mean heights to reach 72 inches, 6 feet (ignoring consideration of sexual dimoprhism, etc.)? Assume that the selection differential is 1 inch and heritability is .5. Iterate.

It will take about 20 generations (20 successive selection events) to reach a mean of 6 feet in mean height, about 400 years. Of course the model is grossly simplified (humans do not have discrete generations obviously), and I am assuming that genetic variation is not exhausted. Nevertheless, there, you see, evolution happens! In fact, if I selected a group of breeders whose mean height was 7 feet I could hit 6 feet as the mean in one generation (this would require a large population since if the mean is 5 feet and the distribution is normal there wouldn't be that mean people north of 6 feet in the first place).1

This wouldn't impress anyone, because people don't think that change in one trait matches their idea of evolution. T-shirts that depict human evolution show a rise in height (that's wrong, it is possible that H. erectus, or at least many populations of this species, were rather taller than the typical post-neolithic human being) as we evolve upward and onward, but, there are also a host of other morphological changes. What we are looking for is phenotypic change over generations on a host of traits. It happens, but never with the rapidity that will satisify commen sense.

Additionally, beyond the problem of the extent of change as a function of time, there is the essentialist paradigm which demands a particular conception of species difference contemporaneously. Unlike "genus" and other taxonomical categories species is more than a human semantic conjuring, they do seem to exist. But, contra the wisdom of the Creationists, and human common sense, it is not clear that species are always cut & dried in terms of how one delineates one "kind" from another. The various ring species are a clear illustration of morphological variance within interbreeding species. Dogs also illustrate part of the problem within themselves they vary a great deal morphologically, but there is debate whether they should separated from wolves, and the reality that some dogs seem more "wolfish" than domesticated, especially when placed next to the more bizarre lap dog morphs. I have already addressed the ecological species concept vs. the biological species concept, but it seems likely that the public simply dovetails all these nuances together and so expects similar theoretical elegance from evolution. I have not even touched on the topic of defining "species" among asexually reproducing prokaryotes, but since they are outside of the realm of the basic senses they are also generally not admissible to the court of common sense.

Evolution as a model is a scientific paradigm scaffolded by all sorts of peculiar realities, contingencies and theoretical constructs, as a fact it works over inhuman timescales and the underlying processes are not always intuitive. Human beings evolved to process an analog world of information, but we are a shaped on the most fundamental level by a discrete information storage medium and replicative process. I believe this is why random genetic drift often surprises people, it is a process that occurs due to imperfect discrete sampling of the previous generation of alleles, while human beings conceive of our replication as an analog process where we recreate the whole. Whether you believe in the evolutionary psychological massively modular mind with its specialized knowledge domains, or you hew to adaptive thinking or even rely on the importance of general cognition primed toward inputs that shape templates and that over time can trigger almost reflexive associations, you acknowledge that our minds are riddled with biases of thought, process and intuition. If you asked a young adult if two metallic balls of very different sizes would hit the ground at the same time if dropped from the same height they would say "yes," but why, common sense? No, I suspect they've been taught this reality as part of their science curriculum from an early age. In the everyday world we don't encounter many dense objects with low surface areas dropped from on high on a straight line so that we can neglect the reality of drag and other vicissitudes. Human life for the past 100,000 years has not been a controlled experiment rigged to elucidate general scientific principles and the abstract laws of the universe, rather, it has been a sloppy mess and a struggle to reproduce. The biases we have been given by evolution or our proximate day to day experience as human beings are useful. If we spent time considering that Newtonian Mechanics is fundamentally a faulty aproximation, that the world around is 99.999999% vacuum, that does nothing for our life and nothing for our reproductive possibilities. We know on a populational level that clines repudiate essentialist ideas of race, that the term has as much ontological substance as "genus" or "phylum," but, on a day to day level we label people as "black" or "white," not 76.45% African on the neutral genome markers, or 94.5% European on the neutral genome markers. But, if we are to talk about human populations in a scientific fashion, to build models, throw up hypotheses to test, then we need to delve into the deep truth of populational thinking and abandon the superficially useful labels in the "common" world.

Over the past 5,000 years a special social system has emerged which has resulted in the generation of a niche for certain individuals to insulate themselves from the caprice of the world, to live a relatively controlled experiment in their lives. Consider the case of Charles Darwin, an independently wealthy gentleman who devoted his life to the study of Natural History. Consider Aristotle, who made his living as a tutor, exploring his own ideas with youths while being paid for it. We are not Bayesian conditional probability calculators because we haven't had to be, the set of possibilites that we will encounter is a tiny scattering in the vast sample space. A few humans though have found a niche where they could explore the nuances of the order of the universe and let their mental capacities be stretched into bizarre counter-intuitive contortions. Today we call these individuals scientists.

Science is hard, science is abnormal, and beware the bewitchment of "common sense." Qasars and quarks, random genetic drift and DNA, such things are difficult to grasp with common sense precisely because their sensory reality is excluded from our universe, not only do we not have direct experience as individuals our species' minds have never been shaped by the patterns and rules which emerge out of their interlocking dance with the rest of the reality. Evolution is the father of this situation, it has equipped us to recognize faces, to keep track of social relationships and fall forward in a controlled fashion without thought. But, evolution could not shape us to understand itself, because it works over millennia, and there is no fitness advantage is conceiving of possibilities deep into the future when the concerns of the present loom large. Perhaps this is another argument against "species" selection, as a species that could "understand" evolution on a communal level might have been able to game the system, enter into new niches, escape overspecialization that might make them vulnerable to reccurent catastrophic events.

Ultimately the issue is not evolution, it is the profound complexity and technicality of the scientific disciplines in the modern world, and the lack of fluency with them that is the norm among lay persons. Evolutionary theory is also problematic because it intersects with the deeply emotional issue of human origins, and when emotion confronts rationality the wisdom of the crowds is not pretty. For the past few hundred years technological change has given science breathing room, the ability to take the population foward over new horizons and into strange lands, but who knows what the future holds?

1 - As you can see, there is regression to the mean since 50% of the variation on the trait isn't genotypically controlled.

Posted by razib at 10:01 PM | | TrackBack

Humans, Neanderthals, and free trade

An interesting new article on TechCentralStation has been posted that discusses the paper, "How Trade Saved Humanity from Biological Exclusion: An Economic Theory of Neanderthal Extinction" (paper is 240 kb, but the server is slow, so give it time). In a good summary of the paper, Jackson Kuhl writes:

To demonstrate that trade might be an innovation that gave humans a competitive advantage, the authors assumed that the primary food of both humans and Neanderthals was meat harvested by hunting. Additionally, they assumed there was a finite amount of available meat ("animal units") for which they both competed. In addition to a non-trading scenario, three trading scenarios develop among humans: one in which skilled hunters hunt and unskilled hunters both hunt and produce other goods; one in which skilled hunters hunt and unskilled hunters only produce other goods; and another in which skilled hunters hunt and produce other goods while unskilled hunters only produce other goods.

In the economists' model, "other goods" may include everything from shelter, clothing, fire, and tools to even intangible services like the spiritual advice and comfort provided by a shaman. Any surplus meat not consumed by the skilled hunters is assumed to go to the unskilled hunters in exchange for their "other goods."

In the latter two scenarios, the authors show that meat consumption rises because the specialization of unskilled hunters solely producing other goods frees the skilled hunters to hunt more. Assuming that increased meat consumption leads to increased fertility which leads to more people hunting, humans who adopted either of these two strategies could have replaced Neanderthals in just a few millennia, even if a biological bias favoring Neanderthals is calculated into the equation.

In a short news article about the paper, "Did Use of Free Trade Cause Neanderthal Extinction?," the authors of the paper state that...

Early humans, the Aurignations and the Gravettians, imported many raw materials over long ranges and their innovations were widely dispersed. Such exchanges of goods and ideas helped early humans to develop “supergroup social mechanisms.” The long-range interchange among different groups kept both cultures going and generated new cultural explosions, Shogren says.

Anthropologists have noted how judicious redistribution of excess resources provides a distinct advantage to “efficient hunters” as measured by factors such as increased survivorship, social prestige, or reproductive opportunities, the researchers say.

“One of the striking features of the archaeological record is that Neanderthal technology was nearly stationary for many thousands of years whereas technology of early humans experienced many innovations,” Shogren says.

So, to put it in the words of Mike Linksvayer, "Anti-trade economics is Neanderthal Economics," and "Anyone who advocates restriction on trade is an Economic Neanderthal."

Hat tips: Arnold Kling

Posted by Arcane at 09:59 PM | | TrackBack

Love Potion Number 9

My blogfather, Joe Katzman sent me this oxytocin link. Lots of good stuff there! Recently we have talked about the neural-hormonal cascades involved in Dr. Helen Fisher's three kinds of love, here, here, and here. I thought about this in the context of Ramez Naam's excellent new book, More Than Human.
Ramez sez (pg. 55):

In the next few decades, this accumulated knowledge base could be used to create new drugs that sculpt or alter any aspect of human behavior: infatuation, empathy, pair bonding, appetite, spirituality, thrill-seeking, arousal, even sexual orientation.....The next step-- a step tens of millions of consumers will pay for...

What do you think, dear readers, would be the first commercial result of this technology that consumers would pay big bucks for? A love philtre? An aphrodisiac? Something to make someone fall into romantic love with you? Or lust? Something to keep your spouse faithful and happy? Or an antidote for the wrenching pangs of unrequited or unresolved romantic love?

Hard to say. But given the success of viagra-like compounds, drugs about sex will be very popular, and may be among the first transhuman technologies to hit the market.

Gentlemen, start your patents. ;)

Posted by jinnderella at 04:14 AM | | TrackBack