genetics
rskloot | March 2, 2009
The other day, the NY Times ran a story called "Picture Emerging on Genetic Risks of IVF. It reported on a new Centers for Disease Control study that found that children conceived through the most common infertility treatments had a slightly increased risk of several birth defects, including cleft palate and septal heart defects.  believe this is one of the largest studies looking into the connection between Assisted Reproductive Technology (ART) and birth defects, but it's not  the first. Â
Way back in 2003, I wrote a story for Popular Science called "Sally Has Two Mommies + One Daddy…
razib | March 1, 2009If you read an older work like The History and Geography of Human Genes based on classical genetic markers Sardinia stands out on charts of genetic distance. This is probably due to the fact that Sardinia is an island and gene flow from surrounding regions is relatively limited due to the physical barriers. So the first settlers have an outsized genetic impact which is not diluted over time by intermarriage with surrounding populations. Additionally, because an island can be treated as an isolate, that reduces effective population and increases the power of random genetic drift, which will…
bioephemera | March 1, 2009
image by Mike Rosulek
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It's a classic question: if Charles Darwin had known about Gregor Mendel's genetic research, would Darwin have realized it was the missing piece he needed to explain how individual variation was inherited and selected? Was it simply bad luck that Darwin never stumbled on the right experiments? Or was Darwin so constrained by his own perspective on inheritance that he couldn't have seen the importance of Mendel's work, even if he had known about it?
Jonathan Howard has written an intriguing overview of this question. He argues that…
amillikan | February 28, 2009
Maybe not nearly as long as many anthropologists believe. That's the thesis of Gregory Cochran's controversial book, The 10,000 Year Explosion, which Gregory discusses with ScienceBlogger Razib Khan of Gene Expression in this week's Science Saturday. They also talk about how the evolution of lactose tolerance might explain why Indo-European languages are widespread, whether the invention of helmets changed our skulls, and the way in which survivors of the Black Plague were doubly lucky.
razib | February 28, 2009You can watch me talk to Greg Cochran about his book The 10,000 Year Explosion on bloggingheads.tv this weekend....
There's something interesting about the front page of bloggingheads.tv right now.
Check it. Not only are the two colored people on the front not talking to each other (yeah, I'm talking about the Glenn & John duo), but both happen to be secular Bangladeshi American Republican males. Who have met each other to boot. Conspiracy? Or coincidence? You decide.
gregladen | February 27, 2009Perhaps we are all subject to falling into the trap of what I call the Hydraulic Theory of Everything. If you eat more you will be bigger, if you eat less you will be smaller. Emotional states are the continuously varying outcome of different levels of a set of hormones, forming "happy" or "stressy" or "angry" cocktails. Your brain is a vessel into which life pours various elixirs. Too much of one thing, and there will not be enough room for something else. Even political arguments are hydraulic. The 'balanced' middle view between two arguments is like the mixture of contrasting primary…
razib | February 26, 2009
Polish Genetics & Anthropology points out that the Estonian Genetics Project is reporting:
The more than 25,000 blood samples collected already make it possible to conduct various background studies. For example, comparing the genetic data of Estonians with other European nations has revealed that Latvians, Lithuanians, Poles and some Russians are genetically much more similar to Estonians than the Finns with whom Estonians share a similar language.
The genetic maps I post on now and then are real popular (invariably they are the ones that sites like reddit pick up), but the sample sizes…
razib | February 25, 2009A few days ago I mentioned that the story about a bumper crop of twins in a German town in southern Brazil was notable because of the elevated frequency of identical, not fraternal, twins. A reader points out that that was an error, and The New York Times has appended a correction:
The Cândido Godói Journal article on Monday, about the unexplained proliferation of twins born in the farming town of Cândido Godói in southern Brazil, misstated the type of twins usually associated with a genetic tendency of the mother. They are fraternal twins -- like a majority of those born in the town.…
clock | February 24, 2009Genetic Manipulation of Pest Species: Ecological and Social Challenges:
In the past 10 years major advances have been made in our ability to build transgenic pest strains that are conditionally sterile, harbor selfish genetic elements, and express anti-pathogen genes. Strategies are being developed that involve release into the environment of transgenic pest strains with such characteristics. These releases could provide more environmentally benign pest management and save endangered species, but steps must be taken to insure that this is the case and that there are no significant health or…
razib | February 24, 2009Wings, Horns, and Butterfly Eyespots: How Do Complex Traits Evolve?:
Complex traits require co-ordinated expression of many transcription factors and signaling pathways to guide their development. Creating a developmental program de novo would involve linking many genes one-by-one, requiring each mutation to drift into fixation, or to confer some selective advantage at every intermediate step in order to spread in the population. While this lengthy process is not completely unlikely, it could be circumvented with fewer steps by recruiting a top regulator of an already existing gene network, i…
razib | February 23, 2009
Mystery of the 'Land of Twins': Something in the Water? Mengele?:
There was no evidence of the use of contraceptives or fertility drugs among the women, nor of any genetic mixing with people of African origin, who have higher twinning rates than caucasians, Dr. Matte said. But the rate of identical twins here, at 47 percent of all twin births, is far higher than the 30 percent that is expected in the general population, she found.
The part about monozygotic (identical) vs. dizygotic is strange. I knew about this village, but not the high frequency of identical twins. The between population…
razib | February 22, 2009I recently got bored and played a joke on Southern Fried Science a few days ago...my usual PC-tard schtick,* see the comments. In any case, the author of the weblog suggests that I was being unkind at his expense. I won't stop playing these sorts of jokes (see this Greg Laden comment thread), but I figured it would be a mitzvah to send some traffic his way. It takes some courage for a privileged white male to attempt to abolish cant when it comes to discussion about race in this nation of cowards.
* My usually method is to not think about what I'm typing, but just stick together random…
edyong | February 22, 2009The trauma of child abuse can last a lifetime, leading to a higher risk of anxiety, depression and suicide further down the line. This link seems obvious, but a group of Canadian scientists have found that it has a genetic basis.
By studying the brains of suicide victims, Patrick McGowan from the Douglas Mental Health University Institute, found that child abuse modifies a gene called NR3C1 that affects a person's ability to deal with stress. The changes it wrought were "epigenetic", meaning that the gene's DNA sequence wasn't altered but it's structure was modified to make it less active.…
razib | February 18, 2009Dienekes points to a paper by Yann, Estimating Genetic Ancestry Proportions from Faces:
Ethnicity can be a means by which people identify themselves and others. This type of identification mediates many kinds of social interactions and may reflect adaptations to a long history of group living in humans. Recent admixture in the US between groups from different continents, and the historically strong emphasis on phenotypic differences between members of these groups, presents an opportunity to examine the degree of concordance between estimates of group membership based on genetic markers and…
razib | February 17, 2009My post below outlining the possible future of genomics and intelligence made me recall a paper from last fall, Predicting Unobserved Phenotypes for Complex Traits from Whole-Genome SNP Data:
Results from recent genome-wide association studies indicate that for most complex traits, there are many loci that contribute to variation in observed phenotype and that the effect of a single variant (single nucleotide polymorphism, SNP) on a phenotype is small. Here, we propose a method that combines the effects of multiple SNPs to make a prediction of a phenotype that has not been observed. We apply…
razib | February 17, 2009Dan the man's post on Race & IQ generated a lot of feedback. A lot. Those of you who are familiar with my weblog oeuvre know I used to be more interested in psychometrics. No more. Rather, if you don't want to believe in IQ or general intelligence, fine. My own experience is that very intelligent people (e.g, Mark, PhD physiology, now getting his MD, undergraduate background in physics) often are the most robust and cogent objectors to IQ or psychometric testing as a relatively useful reflection of intelligence. Dumb people know very well they're dumb, and they're not too coherent or…
razib | February 17, 2009Picture Emerging on Genetic Risks of IVF:
In November, the Centers for Disease Control and Prevention published a paper reporting that babies conceived with IVF, or with a technique in which sperm are injected directly into eggs, have a slightly increased risk of several birth defects, including a hole between the two chambers of the heart, a cleft lip or palate, an improperly developed esophagus and a malformed rectum. The study involved 9,584 babies with birth defects and 4,792 babies without. Among the mothers of babies without birth defects, 1.1 percent had used IVF or related methods,…
razib | February 16, 2009Dan MacArthur's post Should scientists study race and IQ? points to a debate in Nature. Well, scientists are studying genetic variation. And others are engaged in the project of psychometrics. This seems to fall into the category of the economist predicting the past perfectly. Lagging indicators & all. I mean, if we're talking about whole genome sequencing of newborns in 2019....
razib | February 16, 2009p-ter points me to a new paper, Global distribution of genomic diversity underscores rich complex history of continental human populations:
Characterizing patterns of genetic variation within and among human populations is important for understanding human evolutionary history and for careful design of medical genetic studies. Here, we analyze patterns of variation across 443,434 SNPs genotyped in 3,845 individuals from four continental regions. This unique resource allows us to illuminate patterns of diversity in previously under studied populations at the genome-wide scale including Latin…
razib | February 14, 2009Arnold Kling is skeptical that New York City will ever be as important as it was over the past decade because of the prominence of finance. He is responding to Richard Florida's new piece in The Atlantic, How the Crash Will Reshape America. Kling declares:
But I think that a lot of my attitude is that, notwithstanding Virginia Postrel's Substance of Style case for aesthetics, I don't think that the arts are all that important. To me, creative innovation that matters is somebody in a lab at MIT coming up with a more efficient battery or solar cell. It is somebody at Stanford coming up with a…