genetics
evolgen | June 14, 2006Read this reply to Francis Collins on Pharyngula. Collins, one of the biggest movers and shakers behind the human genome project, is also Christian and very eager to tell the world about it. Now he's written a book about his faith. Doc Myers takes Collins to task for the shaky ground upon which his faith rests. I'll go after Collins's total disregard for science in defending his faith.
PZ links to an interview with Collins, in which the director of the US National Human Genome Research Institute's understanding of evolution is described as follows:
Among Collins's most controversial beliefs…
evolgen | June 11, 2006
There's a new blog carnival on the block, and it goes by the name Mendel's Garden. As you can tell from the name, it's all about genetics. If you have a recent genetics post that you would like to contribute to the first rendition, submit it by Thursday, June 15. Thanks to Paul Decelles at the The force that through... for coming up with this.
razib | June 10, 2006Yes, the title is a bit asinine, but it got your attention didn't it? This post is a response to Chad Orzel's response to my response to his response to last week's "Ask a Science Blogger" where I allude to the benefit of tightening labor for our working classes (these United States). Chad states:
...the point is to make it possible for the children of the lower classes to become scientists and engineers rather than factory workers and farmers. Economic class should not be hereditary, and one of the purposes of public education is to keep economic class from being hereditary.
There is a…
pharyngula | June 10, 2006
To continue a bit of theme, I mentioned that there were some different ways to approach biology, and that old-school systematists with their breadth of knowledge about the diversity of life are getting harder and harder to find. This is something I also bring up in my introductory biology course, where we discuss how biologists do their work, and I mention that one distinction you can find (which is really a continuum and frequently breached) is that there are bench scientists and field scientists, and they differ in multiple ways. Bench scientists tend to be strongly reductionist, tend to…
pharyngula | June 8, 2006
The fugu is a famous fish, at least as a Japanese sushi dish containing a potentially lethal neurotoxin that was featured on an episode of The Simpsons. Fugu is a member of the pufferfish group, which have another claim to fame: an extremely small genome, roughly a tenth the size of that of other vertebrates. The genome of several species of pufferfish is being sequenced, and the latest issue of Nature announces the completion of a draft sequence for the green spotted pufferfish, Tetraodon nigroviridis, a small freshwater species.
Tetraodon has about the same number of genes as we do, 20,…
razib | June 8, 2006Evolutionary genetics nerds might find this picture of interest. Look to the top right.
razib | June 7, 2006Over at Genetics & Health Lei is commenting on the genetic character of Shiloh Jolie-Pitt, and referencing an old post of mine on this topic re: genetics. It is all pretty amusing, but, here is a prediction:
The level of spontaneous abortion should be increasing in modern populations
"Spontaneous abortions" are the half of pregnancies which naturally terminate without the woman ever knowing. It is often said that modern populations are subject to relaxed selection, that is, the genetically less fit can, and do, reproduce at a healthy level. Over time this should increase the genetic…
pharyngula | June 6, 2006Last night, I had to read this book RPM mentioned. It's not very long—about 100 pages, counting a preface, an epilogue, and an afterward, and it has lots of pictures—but be warned: it's very inside baseball.
The book is Won for All: How the Drosophila Genome Was Sequenced(amzn/b&n/abe/pwll) by Michael Ashburner, and its subject is the rush to sequence the Drosophila genome in 1998-1999. It's a rather strange twist on what I expected, though. While the subtitle says "How the Drosophila Genome Was Sequenced," there is almost no science at all in the body of the book; instead, it's all about…
pharyngula | June 3, 2006Since Evolgen recognizes the importance of evo-devo, I'll return the favor: bioinformatics is going to be critical to the evo-devo research program, which to date has emphasized the "devo" part with much work on model systems, but is going to put increasing demands on comparative molecular information from genomics and bioinformatics to fulfill the promise of the "evo" part. I'm sitting on a plane flying east, and to pass the time I've been reading a very nice review of the concept of modularity in evo-devo by Paula Mabee (also a fish developmental biologist, and also working in a small…
razib | May 30, 2006PLOS Genetics has a nice review titled The Jewels of Our Genome: The Search for the Genomic Changes Underlying the Evolutionarily Unique Capacities of the Human Brain. It is short and pithy and hits the major points (e.g., SNPs vs. duplications vs. gene expression), so I see no reason to offer any commentary or review of an an already satisfactory commentary and review. If you want original research articles in this area, go here. Some of the material is even open access now.
Update: John Hawks has more.
razib | May 29, 2006I was pointed to this research (via David) that is just out about the correlation between variation on DRD4 and "sexual arousal." From the press release:
Interestingly, some forms of variants in this gene were shown to have a depressing effect on sexual desire, arousal and function, while other common variant had the opposite effect - an increase in the sexual desire score. The latter is believed to be a relatively new mutation, and it is estimated that it appears in Homo sapiens "only" 50,000 years ago at the time of humankind's great exodus from Africa. Approximately 30% of many…
razib | May 23, 2006PLOS has a new paper out which fleshes out how SRY might play a critical role in sex determination in mammals. Here is the press release. Below the fold I've taken figure 7 from their paper and cropped and reedited it a bit for ease of viewing, as well as adding minor parenthetical remarks (e.g., I assume most readers know the common symbol for repression in molecular genetic models, but some might not). Molecular genetics really isn't my thing, but it is good to know if we are interested in the phenotypic impact of a particular locus (e.g., SRY) the particular genotypic dynamics that…
razib | May 23, 2006My post yesterday offered up a quick sketch of the phenomenon of genomic imprinting. In short, genomic imprinting is the selective expression of an allele conditional upon whether it is inherited from the father or mother. This selective expression is limited to a small subset of loci, perhaps about 200 in the typical mammal. These expression patterns often relate to conflicts over resources between offspring and mother, and have fitness implications for all individuals in question, mother, father and offspring. All of this is derived from the initial logic that maternal and paternal…
razib | May 22, 2006Since I'm on a Dumb Vinci Code kick today, check out this amusing article about the genetics of Jesus! Check it:
In humans, females package some of their DNA in two matched X chromosomes, males in a single X and Y. So if you're a male, there's only one way you could have gotten your Y chromosome, and that's from your biological father.
Where would Jesus have gotten his Y?
Where indeed. Perhaps Jesus Christ was an XX male? In other words, he was a clone of Mary that was miraculously possessed of an SRY.
razib | May 22, 2006Some of the most fascinating theoretical evolutionary biology that I've run into emerges out of David's Haig's work on genetic conflict. You've probably stumbled into it somewhere, whether via popularizers like Matt Ridley, or other researchers like Robert Trivers and Sarah Blaffer Hrdy. Haig is a biologist who extrapolates from the familiar axioms of evolutionary genetics and hacks his way through the jungle of derivations and wanders into a world turned upside down. Though his work in the area of mother-offspring genetic conflict in utero is probably what is in widest circulation in the…
razib | May 20, 2006There are reports coming out that Angelina Jolie is going into labor. This is improtant, because last year Armand Leroi spoke about the possible relationship between beauty and low mutational load.
Leroi has posited that one way to decrease the effect of load is hybridization. The logic is simple: assume that each human carries multitudinous deleterious alleles, that is, nasty grams on particular genetic loci. If one assumes that these are predominantly recessive so that their negative implications really manifest themselves disproportionately when they are found in two copies, then…
razib | May 20, 2006A new paper in The American Naturalist should interest some in these parts, Placental Invasiveness Mediates the Evolution of Hybrid Inviability in Mammals:
...Here, we show that the maximum genetic distance at which interspecific mammalian pregnancies yield viable neonates is significantly greater in clades with invasive (hemochorial) placentation than in clades with noninvasive (epitheliochorial or endotheliochorial) placentation. Moreover, sister species with invasive placentation exhibit higher allopatry in their geographic ranges, suggesting that formerly separated populations in mammals…
razib | May 19, 2006Well...the title is a little creepy, but sums up the melange in this report, Study finds that a woman's chances of having twins can be modified by diet. But there is more than diet, researchers have long known that genetics plays a role in twinning rates, it is heritable in that some proportion of the population variation correlates with genotypic variation. And we also know that the rise of fertility medicine has resulted in a boom of multiple births in the modern world. Twinning then neatly encapsulates the manifold aspects of many phenomena of interest which exhibit a biological angle.…
razib | May 17, 2006This dovetails nicely with my previous post on encephalization. Brain size not linked to Microcephalin and ASMP?. Normal Variants of Microcephalin and ASPM Do Not Account for Brain Size Variability:
Normal human brain volume is heritable. The genes responsible for variation in brain volume are not known. Microcephalin (MCPH1) and ASPM (abnormal spindle-like microcephaly associated) have been proposed as candidate genes since mutations in both genes are associated with microcephaly and common variants of each gene are apparently under strong positive selective pressure. In 120 normal…
razib | May 16, 2006John Hawks has the details on the rumors that have been swirling for a while (and now confirmed by a conference talk) about sequencing of autosomal Neandertal DNA. The previous work was mtDNA, which is easier since mitochondria are copious throughout the cell. But, this will give us a lot more information to chew on....