How animals lose legs

What's with manatees in the news lately? First intelligence, and now this:

Manatee Bones Lead To New Insight On Evolution:

"Most research professors spend their days writing grants, teaching and managing graduate students, so when Stanford's David Kingsley, PhD, ventured from his office to his lab, pulled out a scale and started weighing 114 pairs of manatee pelvic bones, it was a sign that something was afoot.

The results of Kingsley's efforts make his departure from the routine worthwhile. He found that in almost every case, the left pelvic bone outweighed the right. Although seemingly trivial in difference--the average left pelvic bone is a mere 10 percent larger than its right-side partner--that difference carries big weight in evolutionary significance. It suggests that mutations in the same gene may be responsible for the evolution of leglessness in animals as distantly related as 1,000-pound manatees in Florida and fish smaller than an index finger living in lakes and streams around the world."

You have to read the whole thing to get the details, but the work suggests that the same genetic mutation is responsible for evolution of leglessness in a vast array of vertebrates - from fish, through snakes, to mammals. A surprisingly general occurence if correct. Or is it really surprising in light of everything we learned from evo-devo over the past couple of decades?


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