Friday, November 09, 2007

The Brainbow   posted by p-ter @ 11/09/2007 08:14:00 AM

Alex Palazzo has a little post on the "brainbow mouse", created using some of the transgenic methods mentioned by amenestic in a post a while back. Each individual neuron in a given mouse brain expresses a random combination of fluorescent proteins, allowing analysis with the naked eye. Pretty amazing stuff.

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Sunday, September 23, 2007

Pro-Choicer Advocates Limits On Reproductive Freedom   posted by TangoMan @ 9/23/2007 12:40:00 PM

Dissent has published an article on how pro-choice advocates should start thinking about the prospects of designer babies and the author broaches the subject of regulating, and perhaps prohibiting, access to such procedures. What's striking about the article is the heavy reliance on the "barn door effect" wherein pro-choice advocates, once through the barn door, slam it shut in order to prevent others from using the same rationales to get through the door. For example:
Now, we who support abortion rights may fear that regulating reproductive technologies could endanger our cause. There is no doubt that maintaining the legality of abortion-and fighting to reverse harmful restrictions of it-is paramount. But it is also important for us to sustain a larger moral vision.

The larger moral vision which the author seeks to protect imposes a cost of loss of reproductive freedom on couples who wish to use reproductive technologies. During the Abortion Wars the pro-choice advocates rejected the very notion of a larger moral vision being protected at the cost of individual reproductive freedom yet now, through the use of selective definition, wherein abortion is synonymous with reproductive freedom and the use of reproductive technologies falls outside the definition, some seem fine with the very idea of limiting individual choice in order to advance their vision of a societal interest.

One of the lines of argument she develops begins with the premise that "individual choices can have larger social consequences." I wonder what the author's response would have been to this same premise being used in the early abortion battles, for abortions themselves also create larger social consequences. As women exercise their individual right to abortion they create effects that ripple through society. The same process is at work with regard to access to birth control.

The author makes much of the arbitrary line in the sand she's drawn wherein she places high value on individual liberty for women to control their own bodies and timing of reproduction yet she devalues the individual choice of embryonic trait selection which leads me to question whether she stands for principle or outcome. If the principle of individual liberty is paramount, as we see with free speech cases where disagreeble speech is frequently defended, then we should expect support for individual exercise of reproductive freedom even when one may personally disagree with the choice made. If the outcome is of the highest importance, then we should see the jettisoning of principle when it is no longer convenient. I believe the author is arguing the latter position and this may come to be exploited by those who oppose her viewpoints on abortion, for if one jettisons principle when it is inconvenient to one's immediate concerns then it becomes harder to argue on the basis of principle when one's position is threatened.

I find it interesting to watch these early stumblings on the question of reproductive technologies and the shifting alliances that may result. Earlier I took a rudimentary stab at outline the shifting alliance in the post The Turning of the Tides. One of the most glaring examples of the conundrum reproductive technologies pose for dogmatic feminists was laid bare within this post, Feminist != Support for Reproductive Rights.

While the ideological contortions are interesting to watch what I find most amazing is the penchant for social engineering by fiat. The belief that legislation which restricts a couple's reproductive choice will adequately address what the author see as a problem and that people shall willingly constrain their reproductive choices. Bush and Kennedy championed a law (NCLB) which mandated that all students shall meet proficiency standards in their educations. How's that working out? Is the War on Drugs eliminating all drugs from society? Before abortion was widely legalized, did laws against abortion prevent abortions from taking place? Do Bio-Luddites really believe that prohibitions on advanced reproductive technologies will eliminate choice for parents? The most likely effect will be to drive such parents to underground providers or to exercise their choice overseas, in countries like China, where attitudes on this topic are quite different:
A survey of Chinese scientists working in the field of genetics suggests they overwhelmingly support eugenics to improve public health.

The theory of eugenics - which is considered highly controversial in the West - suggests that the human race can be improved by selective breeding. The survey, which was conducted in 1993 among 255 geneticists throughout China, was reported in the British magazine New Scientist. Almost unanimously - by 91% - the scientists said that couples who carried the same disease-causing genetic mutation should not be allowed to have children. More than three-quarters believed that governments should require pre-marital tests to detect carriers of hereditary disease. They also supported the routine genetic testing of job applicants by employers. There was also strong backing for the genetic testing of children to see if they are susceptible to problems such as alcoholism.

If the authors worried about a class divide developing between the "GenRich" and the rest of the population then the surest way to bring this about is to create a regulatory framework where only those with means can access the service by traveling overseas in order to have their embryos transfered. Does the author imagine that US Customs will maintain a pregnancy screening service for Americans arriving back in the country, or that abortions will be forced on people who have been found to have used reproductive technologies, or that the children, once born, will be born with a Scarlett Letter emblazoned on their foreheads announcing to the world that they are "GenRich."

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Tuesday, August 14, 2007

Building a better tomato   posted by p-ter @ 8/14/2007 02:39:00 PM

Let's hope these guys come up with a better name than Flavr Savr.
We have modified the flavor and aroma of tomatoes by expressing the Ocimum basilicum geraniol synthase gene under the control of the tomato ripening-specific polygalacturonase promoter. A majority of untrained taste panelists preferred the transgenic fruits over controls. Monoterpene accumulation was at the expense of reduced lycopene accumulation. Similar approaches may be applicable for carotenoid-accumulating fruits and flowers of other species.


Tuesday, August 07, 2007

The genetics of tone deafness   posted by p-ter @ 8/07/2007 03:03:00 PM

There's an "old-school" article in the most recent American Journal of Human Genetics on familial aggregation in tone deafness:
Congenital amusia (commonly known as "tone deafness") is a lifelong impairment of music perception that affects 4% of the population. To estimate whether congenital amusia can be genetically transmitted, its prevalence was quantified by direct auditory testing of 71 members of 9 large families of amusic probands, as well as of 75 members of 10 control families. The results confirm that congenital amusia is expressed by a deficit in processing musical pitch but not musical time and also show that the pitch disorder has a hereditary component. In amusic families, 39% of first-degree relatives have the same cognitive disorder, whereas only 3% have it in the control families. The identification of multiplex families with a high relative risk of experiencing a musical pitch deficit (lambda_s = 10.8; 95% confidence interval 8-13.5) enables the mapping of genetic loci for hereditary amusia.
I imagine it's difficult to get money to study this sort of phenotype, but eventually the technology will be cheap enough. I wonder, though, if any sort of "genetic counseling" company (if such a thing exists) would pony up the cash to find genes involved in tone deafness. Offering the ability to test for and select non-tone deaf embryos for IVF could be a lucrative niche market.

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Sunday, June 03, 2007

Genetics carnivals   posted by Razib @ 6/03/2007 02:10:00 PM

Gene Genie hosted by Hsien at Eye on DNA. Mendel's Garden, over at The Daily Transcript (via evolgen).


Genetic correctness?   posted by p-ter @ 6/03/2007 08:28:00 AM

A rather confused essay by Kurt Jacobsen, published in Logos, has been making the rounds recently. It's about eugenics and what he calls "genetic correctness", apparently his term for the belief in a "correct" genome. It begins:
The advent of Dolly the cloned sheep in 1996 - RIP in 2003 - left many an onlooker feeling both celebrative and uneasy. With irrepressibly manic ingenuity the biological sciences are dissolving our supposedly fuddy-duddy moral boundaries so that many scientists find themselves in debates they really would rather avoid as to the wisdom of playing cavalierly with recombinant DNA.
It's an unfortunate start-- I'm not sure if there's supposed to be a relationship between those two sentences. Cloning (the subject of the first) does not, of course, make use of recombinant DNA (the subject of the second). Read the wikipedia article on recombinant DNA (noting the alternative definition of the word "cloning"), then compare to the technique used for mammalian cloning. They're simply two separate things.

This is perhaps a technical issue, but relevant to his ultimate point. Yes, scientists would rather avoid ethical discussion about recombinant DNA, but one could argue from the other perspective as well-- many ethicists (and really, we're all amateur ethicists) are finding themselves in positions of trying to judge technologies they really don't understand. They can't be bothered to learn all the silly details, so they make an argument from ignorance. This is a case in point.

Much of the essay is an interesting history of the eugenics movement, demonstrating the role of scientists, sensationalist media, and popular hysteria in the forced sterilizations and political movements of the time. Yes, many scientists and pseudo-scientists lent their names to questionable treatments for "feeble-mindedness", and yes, some praised the Nazi eugenics regime. There is much to be learned from such history. But I doubt the role of scientific results themselves in shaping people's political beliefs. I could be wrong, but I find it difficult to believe that many "social Darwinists" were all gung-ho about social programs and helping the poor before reading about the "survival of the fittest", nor do I think many people decided supporting social programs was a great thing after reading about the naturalistic fallacy. It's much easier to search out arguments to support your world-view than to change said world-view in response to facts.

After recounting the rather sordid history of state-sponsored eugenucs, Jacobsen is clearly uncomfortable about modern "eugenics", as the underlying scientific principles are the same. But those underjlying principles are, in fact, correct. Jacobsen writes:
Scientists already found that a stable genotype can correspond to a continuous variations in phenotype, that "many symptoms regarded as pathological might only arise from interaction of genotype with surrounding conditions" and that "a genotype cannot always be derived from phenotype" - findings which should have extinguished the theoretical basis of eugenics.
This is obviously wrong. The entire basis of livestock breeding is based on selection on "quantiative traits" -- traits that show such a "continuous variation in phenotype". The theory is sound -- there's no doubt that, should humanity want to be a little taller, forced sterilization of short people would, over the course of a couple hundred years, get us there.

Jacobsen wants to have it both ways here-- first, he denies that genetics plays a role in disease:
In the 1990s "psychiatric geneticists began to propose genetic anticipation, the tendency of some illness-causing genes to expand in size when passed from generation to generation, as the mechanism behind the increasing severity of schizophrenia or manic-depressive illness as handed down by a family tree." Hence, the problem cannot be family conflict or lousy schools (both rooted in bad social conditions), the child instead is blamed - with the very best intentions - as carrier of disease or a misshapen gene, which supports the biopsychiatric inclination to "reduce human conduct and social conflict to grossly sluggish neurotransmitters in a particular type of nerve cell." It's not begging the question, you see, it's genetic.
Then (after puzzlingly dismissing genetic anticipation. Is it really so much more compassionate to blame a family for causing the increased severity of a disease when it actually is genetic?), he laments the possibility of an increasing role for prenatal genetic testing (which, if he's right and things are just too complicated to understand, shouldn't be able to properly test for anything).
The future holds out the spectacle not of coercive control but of a "eugenics of the free market." Andrews relates a case of an HMO instructing a couple, who found through amniocentesis that their child-to-be possessed a gene for cystic fibrosis, that it would not pay for the child's care if the pregnancy came to term.
It's interesting that Jacobsen wants to make us feel uncomfortable about genetic testing with this anecdote; if anything, it makes me question the insurance system. (and indeed, I've argued before that genomics should provide a push for socialized health care).

I could go on, but this essay is simply a hodge-podge of all the different things that make people uncomfortable about genetics-- designer babies, gene patents, the word "eugenics", something about "reductionism". Oh, and didn't the Nazis like genetics? All the arguments are there, even the contradictory ones and the ones that say more about how some of our infrastucture (the patent system, the insurance system) is unprepared to deal with genetic information than about the genetic information itself.

Related: Notes on eugenics, To breed a better human-we have the technology

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Monday, March 26, 2007

Swappable DNA Module in Bacteria Gives Light Harnessing Ability   posted by Fly @ 3/26/2007 12:17:00 PM

Engineering Bacteria to Harvest Light
Some bacteria, such as cyanobacteria, use photosynthesis to make sugars, just as plants do. But others have a newly discovered ability to harvest light through a different mechanism: using light-activated proteins known as proteorhodopsins, which are similar to proteins found in our retinas. When the protein is bound to a light-sensitive molecule called retinal and hit with light, it pumps positively charged protons across the cell membrane. That creates an electrical gradient that acts as a source of energy, much like the voltage, or electromotive force, supplied by batteries.

First discovered in marine organisms in 2000, scientists recently found that the genes for the proteorhodopsin system - essentially a genetic module that includes the genes that code for both the protein and the enzymes required to produce retinal - are frequently swapped among different microorganisms in the ocean.
Intrigued by the prospect that a single piece of DNA is really all an organism needs to harvest energy from light, the researchers inserted it into E. coli. They found that the microorganisms synthesized all the necessary components and assembled them in the cell membrane, using the system to generate energy.
The findings have implications for both marine ecology and for synthetic biology, an emerging field that aims to design and build new life forms that can perform useful functions. Giant genomic studies of the ocean have found that the rhodopsin system is surprisingly widespread. The fact that a single gene transfer can result in an entirely new functionality helps explain how this genetic module traveled so widely. In fact for microbes, this kind of module swapping may be the rule rather than the exception.