The X chromosome in humans is something of an exception with regards to the rest of the genome–as it’s diploid only in females, the population genetic forces on it are slightly different. In particular, the effective population size of loci on the X, in a standard neutral model, is 3/4 that of the autosomes. In different demographic models, this fraction can change, so comparing the X to the autosomes is potentially an important tool for understanding human demography.

In a paper published earlier this year, Hammer et al. analysed a data set they had collected of sequences at 40 loci (20 autosomal and 20 on the X) in a number of populations. They saw a striking pattern (the relevant figure from their paper is on the right): in every population they looked at, their estimate of the ratio of effective population sizes on the X and autosomes was greater than 0.75. After additional analyses, they interpreted this as the signature of polygamy in human history.

At the same time, another group (Keinan et al.) was independently looking at this issue in other datasets. Their analysis, published today is markedly different. In particular, they see the exact opposite of the pattern in Hammer et al.–a decrease in the X/autosome ratio in effective population size compared to 0.75 (a figure from their paper is on the right. Note that the y-axis is the same in both this and the Hammer et al. figure–the x/autosome ratio in Ne. In both, the solid horizontal line is at 0.75). . And this is not due to extremely different methodologies–one of the analyses presented by Keinan et al. is very similar to that in Hammer et al., only using different data.

So this is all a bit odd, to say the least.

In the social circles I move in there is a lot of concern with overpopulation. Now, it is somewhat ironic to me that those who are concerned do not tend to breed so as to be virtuous…while others who are not so concerned, such as Sarah Palin (and also these ladies and gentlemen) make up for the balance (and some!) and render the valiant efforts of the concerned rather moot. In any case, I had a thought today…I remember when I was a small child that world population was between 4 and 5 billion. Today is between 6 and 7 billion. That is rather staggering…that my lifetime has witnessed the birth of billions. I’m not that old.

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I remember that back in mid-2007 I was mooting the possibility of a recession. Part of the reason was that I’d been looking at the statistical trendlines in real estate MLS data at the time for a software project, and I’d been getting a bad feeling from the summer of 2006 on (the flip rates in many markets were not going in a “good” direction). Check out the comments. Days of innocence….

The paperback edition of “Dow, 30,000 by 2008” Why It’s Different This Time came out on the 1st of this month on Amazon. I guess publishing schedules are fixed so that at a date is a date? Here’s the most amusing of the “reviews” on Amazon (4 out of 4 stars by the way):

A Prescient Mind – Spot On!
What a brilliant, insightful tome on investing cycles. The author makes an iron clad case as to why the Dow will skyrocket to the stratosphere by 2008. I can find NO FAULT in his logic. Leverage is the key to success in this world of ours. Everybody should borrow against ANY asset that they have, especially their home, up to 30 or 40 times the fair market value. As everyone knows, homes NEVER decrease in value.

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Mark Chu-Carroll has a “must read” post, Fitness Landscapes, Evolution, and Smuggling Information:

If you look at the evolutionary process, it’s most like the iterative search process described towards the beginning of this post. The “search function” isn’t really static over time; it’s constantly changing. At any point in time, you can loosely think of the search function for a given species as exploring some set of mutations, and selecting the ones that allow them to survive. After a step, you’ve got a new population, which is going to have new mutations to explore. So the search function itself is changing. And how is it changing? Modelled mathematically, it’s changing by incorporating information about the landscape.

Read the whole thing for context. If you are interested in the topic from a biological perspective, Sergey Gavrilets’ has published a fair number of papers on this topic….

The blog Strange Maps is candy to a data fiend. I think most readers are aware that I’m one who believes that a thick network of historical & geographic information can be extremely useful in understanding the present; too many people forget that intelligence and ignorance get along just fine. But about a week ago there was a map which leaves you at a loss for words. First a description:

Mr Hecht did some overlay work, and came up with this remarkable fit: “The divide between the (more free-market) PO and the (more populist) PiS almost exactly follows the old border between Imperial Germany and Imperial Russia, as it ran through Poland! How about that for a long-lasting cultural heritage?!?” How about: amazing, bordering on the unbelievable?

Map below the fold (edited for greater clarity).

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A number of papers out this week (summarized here) notice, using various technologies, the presence of extensive transcription off both DNA strands around active promoters. A figure from one of the papers is above–note the peak in transcription from the sense strand just downstream of the transcription start site (TSS), and the peak in anti-sense transcription just upstream of the TSS. This is an interesting observation, and an example of the unexpected things you can see with new technologies, but no one is exactly sure what to make of it–it could just be the transcriptional machinery being a bit sloppy.

Just a weird historical-genetic note, the radical decentralist Republican John Randolph likely suffered from Klinefelter’s syndrome (XXY as opposed to XY). In What Hath God Wrought: The Transformation of America, 1815-1848 the author claims that Randolph’s rumored anatomical peculiarities were confirmed postmortem. I only make note of this because it seems strange to me (I don’t know why) that the paleoconservative John Randolph Club would be named after a childless eccentric who was likely genetically abnormal. Then again, it also struck me as peculiar that a conservative Christian college based out of Manhattan would name some of its fraternities and sororities after avowed freethinkers.

The New York Times just published the definitive Bernie Madoff piece so far, Madoff Scheme Kept Rippling Outward, Across Borders. Reading about Madoff, I can’t help but think about this conversation attributed to J. P. Morgan:

Untermyer: “Is not commercial credit based primarily upon money or property?”
Morgan: “No sir. The first thing is character.”
Untermyer: “Before money or property?”
Morgan: “Before money or property or anything else. Money cannot buy it…because a man I do not trust could not get money from me on all the bonds in Christendom.”

That sir, was the problem of course. And this sort of behavior:

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This is really weird, New World Post-pandemic Reforestation Helped Start Little Ice Age, Say Scientists:

Stanford University researchers have conducted a comprehensive analysis of data detailing the amount of charcoal contained in soils and lake sediments at the sites of both pre-Columbian population centers in the Americas and in sparsely populated surrounding regions. They concluded that reforestation of agricultural lands–abandoned as the population collapsed–pulled so much carbon out of the atmosphere that it helped trigger a period of global cooling, at its most intense from approximately 1500 to 1750, known as the Little Ice Age.

The same researchers published a paper on this last spring, Effects of syn-pandemic fire reduction and reforestation in the tropical Americas on atmospheric CO2 during European conquest:

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