First, here's the real logic behind twin studies (not the bastardized version given in the Slate article). Siblings and twins are more genetically similar than two randomly chosen members of a population. Here's where the confusion typically begins. As a shorthand, people often say, "siblings and dizygotic (fraternal) twins share 50% of their genes." That's sort of true, but also misleading, because all humans have about 99.9% of their genomes in common. Out of about 3 billion base pairs, two people typically vary by a few million only. So siblings clearly share more than 50% of their genomes. A more precise statement about siblings would be "siblings and fraternal twins, on average, have only 50% of the genetic variance of two randomly chosen people."
Wednesday, August 24, 2011
Whoa! What's with this article? For something that makes some really good points, and forces me to somewhat re-evaluate my own view of the implication of twin studies, the good points are buried beneath poorly worded (at best) or completely bungled (at worst) statements about genetics and heritability. The argument reflects a common misconception about the very concept of heritability, and is in fact, somewhat self-defeating.
While we're on the subject, I was just reading this little guy about religion and morality in the Times. Just in the first two paragraphs it highlights and interesting conflict for most theists: are they really worshipping God, or some moral code that is in fact above God? This tension was on full display in the book mentioned in the post below this one. The most hard-core believers, the fanatics, tend to heed God's word (however they interpret it) with no moral filter, which is what leads to anti-social and seemingly immoral acts on the part of the true believers. Indeed, most doctrines and holy books tend to put God ahead of any moral code; thus the all sorts of gruesome things that God orders in the Old Testament, or the belief that you can only be saved if you believe Christ is your savior, etc. etc.
But for most rank-and-file religious folk, the hierarchy is switched (or so it seems to me). They don't think it's right to murder in the name of God, but see religion as a gateway or a path to a moral life (and so would say God would never have such a desire anyway). They tend not to think it's critical to believe in the one true faith that they adhere to. But then what's the point of religious faith if God answers to some higher moral calling anyway? Isn't that moral framework then, like, the whole point?
Monday, August 22, 2011
I just read an awesome book about the history of Mormonism and the modern fundamentalists (the latter are really crazy! There are pockets of thousands of fundamentalists living in essentially totalitarian communities, like, right now! In the US!). Somehow I have managed to survive in complete ignorance of everything Mormon through high school (thank you, GDS american history!) and college (well that was my fault I only took one history class...fuck), and despite the fact that Mormons used to live in my basement. In my defense, they moved out when I was five (?) on account of having too many babies.
Of the many aspects of Mormonism that make it so incredibly fascinating is the fact that it was gettin' started recently enough that there's such a rich record of its origins, which, unfortunately for Mormons, this don't make for the most flattering picture. It also makes various claims in the Book of Mormon eminently falsifiable, like the fact that all Native Americans are descended from the Israelites (DNA sequencing has shown their last common ancestor to be much older).