Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

Health

Complex traits & evolution - follow up

Gene ExpressionBy Razib KhanDecember 19, 2008 1:46 AM

Newsletter

Sign up for our email newsletter for the latest science news

Mike White finally left a comment on my post Complex traits & evolution:

I'm trying to make a distinction between what geneticists call complex or quantitative traits (traits affected by different alleles of many different genes, with a quantitative range of phenotypes), and something I would call a physiologically complex (or complicated) trait. Complex or quantitative traits include both height and intelligence. But I'm arguing that something like height is not physiologically complex the way intelligence is. ... So, for example, in the case of height, you can imagine that it is easy for a single allele of large effect to reach high frequency in a given population, resulting in a fairly tall (or short) population. I don't think that such a thing is very likely for intelligence, because, unlike what I think is the case for height, single alleles of large effect on intelligence probably also have large deleterious effects (like neurological disorders) - something like intelligence is so physiologically complex that it is much easier to 'break' with a large-effect allele than something like stature, where an allele that extends how long growth plates in your leg bones are active (for example) is unlikely to also have major deleterious effects. And to get race-specific differences, given current human genetic variation,

you need single alleles with large effects - thus you have genetic differences between populations in height and skin color, but not IQ.

I disagree that alleles of large effect are necessary. We already have a large range of extant variation across human populations. From what I can tell about the Breeder's Equation QTLs of large effect are not needed.

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.

    Subscribe

    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%

    Subscribe

    Already a subscriber? Register or Log In