genetics
razib | April 7, 2006Nancy Etcoff has a nice piece about twins, genetic predispositions, context and psychology.
razib | April 6, 2006I have just finished reading No Two Alike by Judith Rich Harris. A review will be forthcoming, after I've digested the material and can offer up some coherent reflections. But one of the things that is great about Harris' book is that its review of the literature is both thorough and engaging. In one of the last chapters she points to the research of Mary Cover Jones published in 1957 in Child Development, "The later careers of boys who were early- or late- maturing." In short, the research suggests that late maturing boys are disadvantaged in the dominance game for their whole lives in…
razib | April 5, 2006Evolgen has an interesting post about going to a math department seminar where the topic was genomics. He goes over some questions mathematicians had about biology and their misconceptions. I don't know...I talked to a woman this January who has an undergraduate math degree, and she told her boyfriend (a friend of mine) that she was surprised that biology could be interesting!
razib | April 4, 2006Seed has a new in house weblog, Stochastic, and our resident intern Katherine Sharpe is asking about the best science books for laypeople...which would be a long list. But, I can unhesitantly offer the most influential science book in terms of making me explore many domains of the natural sciences and their intersection with our species' history and social development: Cosmos, by Carl Sagan.
razib | April 1, 2006Just noticed that there is now an epigenetics weblog out there. Epigenetics is one of those terms you have to know...and it seems that this new weblog doesn't just follow model organisms (e.g., S. cerevisiae) but tries to tie the topic humans.
razib | March 30, 2006Interesting paper out in JAMA, Coffee, CYP1A2 genotype, and risk of myocardial infarction:
The association between coffee intake and risk of myocardial infarction (MI) remains controversial. Coffee is a major source of caffeine, which is metabolized by the polymorphic cytochrome P450 1A2 (CYP1A2) enzyme. Individuals who are homozygous for the CYP1A2*1A allele are "rapid" caffeine metabolizers, whereas carriers of the variant CYP1A2*1F are "slow" caffeine metabolizers....Intake of coffee was associated with an increased risk of nonfatal MI only among individuals with slow caffeine metabolism…
razib | March 29, 2006You want to know what John Hawks sounds like? He'll be on Radio Open Source tomorrow (there should be a web feed). I talked to David Miller about getting John on the show before he became famous in Slate, so I am going to take a little credit for this. John and Spencer Wells will be "facing off." John, can you ask Spencer to make his email address more accessible? I'm tired of people emailing me and asking about ways to contact him!
Update: John was really amused throughout the whole show. Spencer Wells asked kind of sarcastically (?) if I was "Richard Dawkins." No, I'm not, Spencer :)…
evolgen | March 27, 2006My little screed on junk DNA elicited some good feedback, including a comment from Dan Graur. In a somewhat ill-thought out rant, I implied that anyone who uses the term 'junk DNA' should be ostracized from the scientific community (or something along those lines). I restated my opinion in a far more diplomatic manner in the discussion that followed in the comments: junk DNA is an appropriate term for DNA that serves no function (non-transcribed, non-regulatory, and non-structural), but we should refrain from using that term for all non-coding DNA. I elaborate my opinion and reference a…
razib | March 26, 2006Apropos of my earlier post relating to heritability...this is the sort of confusing gibberish that ends up making it into the press, Professor researches genetics of gambling. He tries to clear up problems of communication:
This quote has been misconstrued. In the logical development of any investigation of the genetics of a disorder, once something is shown to run in families and appears to have some heritable component, molecular genetic approaches follow. Studies can be done with small numbers of DNA samples, as I propose doing, but definitive studies require thousands of DNA samples. I…
razib | March 26, 2006There is an important paper out on calculating heritability (JAVA applet). Heritability is an important and misunderstood concept. Some people have argued that heritability is fallacious reification, a biostatistical construct which has no real relevance (or reality) outside of its utility in quantitative genetic models. But its entwinement with various concepts within evolution and genetics means it can't be ignored, love it or hate it.1 Heritability is the proportion of phenotypic variation within a population that is attributable to genotypic variation.
This has two quick…
razib | March 24, 2006Well, I've been having fun reading John Hawks' posts on the term "genomics," and I'm sure Evolgen thinks I'm a bit too preoccupied with the three old thugs of population genetics...but this article, Marriage of Math and Genetics Forges New Scientific Landscape is kind of funny, the past is the future! After all, both R.A. Fisher and J.B.S. Haldane were trained as mathematicians, and Sewall Wright was a lover who regretted his early lack of experience. Over a year ago PLOS had a article out, Mathematics Is Biology's Next Microscope, Only Better; Biology Is Mathematics' Next Physics, Only…
razib | March 21, 2006A review paper worth checking out in Molecular Ecology, Variation within and among species in gene expression: raw material for evolution. The salient bit:
We find: (i) microarray-based measures of gene expression are precise given appropriate experimental design; (ii) there is large inter-individual variation, which is composed of a minor nongenetic component and a large heritable component; (iii) variation among populations and species appears to be affected primarily by neutral drift and stabilizing selection, and to a lesser degree by directional selection; and (iv) neutral evolutionary…
razib | March 21, 2006Well, because sometimes it results in babies born without eyes! Detailed commentary here. Think the title is asinine? Well, the National Society of Genetic Counselors suggests that cultural respect trumps individual and social prudence. In Britain cultural sensitivity has resulted in serious consequences for their Health Service. Man is not an island, he swims in the sea of his fellows (only a quasi-libertarian would state that as if that was news! I plead guilty)....
pharyngula | March 20, 2006
What has always attracted me to developmental biology is the ability to see the unfolding of pattern—simplicity becomes complexity in a process made up of small steps, comprehensible physical and chemical interactions that build a series of states leading to a mostly robust conclusion. It's a bit like Conway's Game of Life in reverse, where we see the patterns and can manipulate them to some degree, but we don't know the underlying rules, and that's our job—to puzzle out how it all works.
Another fascinating aspect of development is that all the intricate, precise steps are carried out…
razib | March 20, 2006In my post below where I try to synthesize The Superficial and The Causes of Evolution I used the term "fitness." Well...as Matt McIntosh pointed out the term itself is problematic, and so using it as a reference of any sort is really sketchy. Evolgen has slammed the use of "genetic load", and I I think the skepticism is warranted to some extent. The originator of the formula for genetic load, JBS Haldane, famously quipped "fitness is a bugger!" Part of the problem is that the term "fitness" has unique connotations in evolutionary biology. Physical fitness, health and longevity, often…
razib | March 19, 2006Angelina Jolie and Brad Pitt are classic "beautiful people." By now you know they are going to have a baby. What sort of child will this be? Handbag.com offers you a projection:
Not half bad. Certainly more traditionally beautiful than the Brit Rock look-alike produced by Jennifer Garner and Ben Affleck.
Why are Brad Pit and Angelina Jolie so beautiful? Neither of them were raised in dire circumstances, but likely they have a "genetic leg up." In any given population there will be a genetic load, a number of deleterious alleles which decrease average population fitness from the…
evolgen | March 19, 2006The human Y, that is. The Science Creative Quarterly has a very thorough (ie, make sure you have some time to spare) review of the mammalian Y chromosome (focusing on the human Y). The article covers the origin and evolution of the mammalian Y and what the degeneration of the Y means for the future of human male fertility and sex determination. I should point out that the mammalian Y chromosome is an anomaly in origin and sex determination. In fact, every single sex determination system and sex chromosome system that I know of differs from all of the others in some manner. It looks like…
razib | March 17, 2006Steve Olson in Why We're All Jesus' Children has a gimmicky exposition on the reticulated character of our genealogies. But Olson tries to pull a fast one here:
It gets even stranger. Say you go back 120 generations, to about the year 1000 B.C. According to the results presented in our Nature paper, your ancestors then included everyone in the world who has descendants living today. And if you compared a list of your ancestors with a list of anyone else's ancestors, the names on the two lists would be identical.
The reality is that quantity, not quality, counts, you need to know how many…
pharyngula | March 16, 2006Both Twisty and Amanda seem a bit weirded out by this news that the fetus can be viewed as a kind of parasite. This story has been around long enough that a lot of us just take it for granted—I wrote about the example of preeclampsia a while back.
There are worse feminist-troubling theories out there, though. In particular, there is the idea of intersexual evolutionary conflict and male-induced harm. In species where there is some level of promiscuity, it can be to the male's evolutionary advantage to compel his mate to a) invest more effort in his immediate progeny, b) increase her short-…
razib | March 15, 2006John Hawks has a piece in Slate critiquing the recent scientific genealogy trend. Congrats for John for going "mainstream," and kudos for Slate to contributing something substantive to the discourse. And I've noted before, most of the people taking the tests won't find out anything they don't know....