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

Are we still evolving....

Gene ExpressionBy Razib KhanMarch 2, 2011 12:23 AM

Newsletter

Sign up for our email newsletter for the latest science news

The question whether humans are still evolving is something that crops up now and then. If the story is British you know that the evolutionary geneticist Steve Jones will be approached for his obligatory quote. There's apparently going to be a program today in Britain about continuing human evolution. You can already watch it online if you are British. In any case, there's at least going to be some balanced treatment if this BBC story is representative. Two quick points which I think need to be emphasized: - When we talk about natural selection there's too often a focus on nature. Exogenous shocks. A lot of intra-specific competition occurs between individuals, without nature intervening. Jacob Zuma has 20 children. Barack Obama has 2. If there are some differences in inherited trait values, then there's some selection going on right there. - Steve Jones likes to point out that death rates are low today compared to the historic average. But we're ignoring that ~2/3 of fertilized eggs are subject to spontaneous abortion. There's probably natural selection going on at this stage, and it may be that as more and more genetic load accumulates in human populations due to lack of death and, later conception and gestation, the miscarriage rate will increase concomitantly in a classic pattern of mutation-selection balance. A major difference between classical physics and biology is that because of evolutionary adaptive processes biology's parameters are protean. We may talk today about the end of natural selection, but the specter of infectious disease looms larger and larger with every coming year due to the rise of resistant bacteria. The Red Queen's race is still on.

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