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

Landlubber Genes

Newsletter

Sign up for our email newsletter for the latest science news

Several hundred million years ago, fishlike creatures developed rudimentary fingers and toes, which helped them drag their way onto dry terrain. At Harvard Medical School, developmental biologist Susan Dymecki just found a crucial genetic step that gave rise to those indispensable digits. Dymecki normally studies how genes shape the brains of mice. In a largely trial-and-error process, she and her lab workers manipulate the mouse genome to see how different parts of the brain develop. These experiments produced an unexpected mutation: an animal that lacked fingers and toes. Dymecki found she had knocked out the DNA sequence activating a gene called BMPRIB, which evidently contains the genetic information that sculpts cartilage into digits.

When switched on by a different stretch of DNA, BMPRIB becomes active within the brain. "We think that the sequence we knocked out was acquired sometime later during evolution, and it led to the gene being expressed not just in the nervous system but also in the limb," Dymecki says

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