Expose a person to sunlight, and odds are the UV rays will jump-start a pathway leading to an increase in skin pigmentation, i.e. tanning. However, some people simply don’t tan. These people often, one may have noticed, have red hair. It’s no coincidence– there’s a well-known association between fair skin, red hair, and a defective […]

The abstract for this article by Adam Eyre-Walker (whose work I’ve quibbled with before) caught my eye: The role of positive darwinian selection in evolution at the molecular level has been keenly debated for many years, with little resolution. However, a recent increase in DNA sequence data and the development of new methods of analysis […]

Recently, there has been great interest in the role of epigenetics in the generation of phenotypes. One major question is whether epigenetic mutations can be passed through the germline, as the genome is demethylated, then remethylated, during development. A new paper provides evidence one example of an inherited epimutation, plus an association with the development […]

ZipCodeStats.com. The title says it all.

One of the recurring themes on this blog is that different populations differ genetically, and that these differences have major importance in public policy and health. Jason Malloy has passed on a link to one project that aims to inject genetic information into public health decisions: the PharmacoGenetics for Every Nation Initiative (PGENI). Under the […]

I just finished Carl Zimmer‘s excellent book At the Water’s Edge, a general audience recounting of two major events in macroevolution–the evolution of tetrapods and of whales. One of the major recurring themes is how past events in evolution constrain the probability space of the future. This passage (in a section describing Hox genes and […]

The most recent issue of the Lancet has an interesting case study: a child overdosing on morphine acquired through the breast milk of her mother (who was taking codeine, a chemical precursor to morphine). Normally, codeine is considered safe for nursing mothers. What happened here? If turns out that newborns have trouble metabolizing morphine, but […]

I just saw a re-run of a Charlie Rose roundtable discussion with EO Wilson and James Watson from last year. The free video is here; check out the bit starting around 44.30 for their comments on recent human evolution, natural human variation, and where biology (especially genetics) is headed. According to them, this is the […]

I started writing a summary of this interesting article on pig evolution, but hell, it’s in PLoS, so they’ve already done the work for me. Here’s the synopsis: Brown adipose tissue (BAT) is unique to mammals. It is rich in mitochondria and generates heat to maintain body temperature during cold stress, referred to as nonshivering […]

The transcript of Francis Collins’s speech at the 2005 meeting of the American Society of Human Genetics was published in the most recent American Journal of Human Genetics. In it, he comments on the prospects of genome-wide association testing to find variants involved in complex disease. Not everyone thinks it will pay off as a […]

John Hawks and Tara Smith both have posts on a New York Times article describing the role of events during development on health later in life. A recent article pushed for the development of a framework to describe these kind of effects. The basic concept is simple: during development (development in utero), the fetus recieves […]

A paper in Nature Genetics describes a mutation in a tomato gene that leads to fruits that don’t ripen. This would be an important discovery in itself–the ripening of fruits is certainly an economically interesting trait–but a further twist makes it even more interesting. The twist: the mutation is actually an epimutation. That is, the […]

Twin studies have somewhat fallen out of favor in genetics– instead of estimating parameters like the heritability of a trait, it’s now common to simply skip to studies designed to locate genes that play a role in them. If the heritability turns out to be zero, then, well, not a whole lot is going to […]

In September of last year, Bruce Lahn’s group at the University of Chicago published two articles in Science arguing that two genes which, when mutated, cause microencephaly had recently been (and possibly currently are) under selection in humans. The phenotype under selection was (and still is) unclear, but the fact that mutations in the genes […]

So. A red card for head-butting a dude in the chest, and the career of Zinedine Zidane is over. I’ve got to disagree with Alex Palazzo at The Daily Transcript on this one: that card may have cost France the game. But hey, what aggressive player doesn’t blow his top once in a while? And […]

Regular readers know that ASPM is a microencephaly gene under selection in humans, though the particular pressure driving the selection is unknown. A group of Spanish researchers decided to test whether there is an association between variants of the gene and schizophrenia. The result: nothing. Of course, with only 233 cases and 161 controls, the […]

So I recently tried to google my way to a decent biologist-but-not-statistical-geneticist summary of the difference in two approaches to gene mapping: linkage and association. I didn’t really find anything that did a good job of expressing what, in my opinion, needs to be expressed. So here’s my attempt to fill that void: I. Linkage […]

When looking for genes or alleles involved in a phenotype, especially “complex” phenotypes where many genetic factors are involved, the most powerful approach is often an association study– type a large number of variants in some cases and some controls (or just a bunch of people if you’re talking about a quantitive trait) and see […]

Via Free Association comes a profile of Craig Venter, the so-called “maverick biologist”. 1. Apparently Venter is going to be publishing his own genome sequence shortly and making it publicly available, which is pretty cool. If technically trivial, would you do the same? I’ll go ahead and say I would–Venter makes the good point that […]

Before you read this, check out Razib’s excellent 10 questions with Jim Crow, which I am unfortunately knocking off the top of the blog. So a little while back, I wrote about a paper describing the evolution of a bacteria over the course of an infection (Aetiology also had a post–a better one, truth be […]