CapitalistImperialistPig

Steve Hsu leads us to a new paper which finds evidence of recent selection for the polygenic traits height, educational attainment, and "self reported unibrow." Steve is particularly interested in the evidence for selection for genes associated (with educational attainment in Europeans) in East Asians. That selection appears to have occurred during the past 10,000 years. Although the paper is about 84 pages, most of that is figures and tables, with only about 19 pages of exposition. I found it more understandable than Steve's very brief summary. It's probably obvious that selection is important for polygenic traits, since most significant differences are polygenic, but data to date has been sparse. From the abstract: An open question in human evolution is the importance of polygenic adaptation: adaptive changes in the mean of a multifactorial trait due to shifts in allele frequencies across many loci. In recent years, several methods have been developed to d...

Choose your parents wisely. That's at least partly because of genetics. A new study of 300,000 individuals reported in this week's Nature found 74 variant loci associated with educational attainment. From the Abstract: Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends our earlier discovery sample1, 2 of 101,069 individuals to 293,723 individuals, and a replication study in an independent sample of 111,349 individuals from the UK Biobank. We identify 74 genome-wide significant loci associated with the number of years of schooling completed. Single-nucleotide polymorphisms associated with educational attainment are disproportionately found in genomic regions regulating gene expression in the fetal brain. Candidate genes are preferentially expressed in neural tissue, especially during the prenatal period, and enriched for biological pathways involved in neural development. Our findings demonstrate that, even for a beh...

The deepest mystery in biology, and in science generally, is the origin of life and the genetic code. Life as we know it cannot exist without DNA and the information it stores. But DNA and the genetic code cannot have come before life because it takes a vast and intricate system of molecular machines just to reproduce DNA and translate it into the proteins that do the actual business of metabolism and constitute the machinery of life, including all the machinery to turn DNA into protein. It's the chicken and egg problem in it's sharpest molecular form. DNA is not translated directly into protein. First it must be transcribed into messenger RNA, which in turn is translated into protein by a complex apparatus that consists of proteins and other kinds of RNA molecules. This fact is probably one element that suggested that maybe RNA was the molecule that came before gene and protein. Proteins are the most versatile components of our molecular machinery, acting as structural e...

Probably no intellectual tool is more powerful than that of abstraction - the ability to see analogies and the development of general rules that apply to diverse and apparently different situations. Our most powerful tool for abstraction is language - itself a peculiarly potent abstraction from reality, creating a deep analogy between sound patterns and the events and objects of the world. Language, though, is itself kind of an analogy with some mostly pre-existing representations of the world that exist in our minds. This strongly implies that humans didn't invent abstraction or analogy. The most fundamental abstraction we know of seems to be the genetic code. Patterns of nucleotides in DNA are translated through a vast and complicated apparatus into proteins and all the mechanisms that support life.

Andrew Sullivan and Ta-Nahisi are thumping away at that old meme of "race as a social construct." Well, all our concepts are, you know. One point that is absolutely clear is that there are no magic lines which one can use to divide humans neatly into three, five, or twenty-seven clear and distinct races. At the same time, most of us can look at another of us and guess something about where most of our ancestors came from. Populations differ on average, and differed more before the modern era started moving people around in large numbers. It's perfectly obvious that there are systematic differences, some of them easy to recognize, between populations that have lived in Europe or the Congo for six hundred years. Some of those differences will persist in those with some ancestry from one place or another that that have lived in another place for a couple of hundred years. The fact that race is a social construct, with no absolute biological undepinning does not say a...

Something like 3500 Mendelian (single gene) genetic diseases have been discovered but the vast majority of our genetic diseases appear to be multi-genic. Something like 90 genes are known to be associated with Schizophrenia. Some of these involve proteins that have functions that can be directly linked to the brain. Four of them code subunits of a calcium channel protein, that is, a protein involved in the flow of ions into and out of cells, known to be active in nerve cells. Elucidating the exact way each of these contribute to disease will take a while, but diseases are not the only area where modern genomic statistical analysis will elucidate genetic influence. Height, running speed, and adult IQ are all other areas known or strongly suspected to be under the control of multiple genes. Genomic analysis has developed powerful tools for discovering the function of identified genes, and investigators have gotten rather good at designing customized mice. The designer human will a...

It's a commonplace but rarely appreciated fact that our planet is being managed mainly for the convenience of a bunch of billion year-olds. These ancient ones have been around almost since the formation of the planet. They change very slowly, just a few little tweaks every million years or so. They are parasites of a sort, carrying on their business in fish, trees, people and even bacteria. Of course if they were the sort to talk, they might say it differently. They might say that the bacteria, trees, and people are just convenient dwelling spaces they have devised for their accomodation. I'm writing, of course, about the society of DNA molecules, each of them a clone of a clone and descended in unbroken lineage from some first DNA molecule 3.5 billion years or so ago. With DNA clones though, there is little distinction between the copy and the original, since each new molecule incorporates half of the original and is a copy of it, so in effect each of those DNAs today *i...

Via Tyler Cowen , it seems that China is taking a serious look at the genetics of IQ. At a former paper-printing factory in Hong Kong, a 20-year-old wunderkind named Zhao Bowen has embarked on a challenging and potentially controversial quest: uncovering the genetics of intelligence. DNA samples from the super smart are being scarfed up and fed to 100 powerful gene sequencing machines. Evidently, the effort is patterned on a previous analysis that elucidated some of the genetics of height. Apparently it took DNA from about 10000 people to isolate 1000 genes that make you tall. "People have chosen to ignore the genetics of intelligence for a long time," said Mr. Zhao, who hopes to publish his team's initial findings this summer. "People believe it's a controversial topic, especially in the West. That's not the case in China," where IQ studies are regarded more as a scientific challenge and therefore are easier to fund. The roots of intelligence are a ...

Blue eyes seem to be a rare example of a genetic trait that originated relatively recently (6000-10000 years ago) and spread aggressively. All blue-eyed individuals now alive appear to be descended from a single individual . The trait has spread very widely through Europe and the Middle East, and has nearly completely displaced brown eyes in several parts of the world (99% in Estonia) even though blue eyes represent only 2% of the World population. Since blue eyes are usually recessive, the large number of blue-eyed individuals in some populations suggests a significant selective advantage. This is somewhat surprising in that blue eyes are very rare among mammals in general. I have heard anecdotal claims that blue-eyed individuals see better in the dark.