Sperm Whales Have an "Eve"

All of the sperm whales in the world descended from just one female who lived tens of thousands of years ago. That surprising result comes from an examination of the mitochondrial DNA of more than 1,600 sperm whales from all over the world. Fittingly, researchers have named her Eve.

Mitochondrial DNA is only passed from mother to child, explains the study’s lead authorAlana Alexander, a postdoctoral researcher at the University of Kansas, who conducted the research while she was a doctoral student at Oregon State University (OSU).

Alexander initially tested the samples at the behest of the nonprofit whale conservation organization Ocean Alliance. The organization had previously shown that sperm whales carry toxic levels of heavy metals in their bodies, and they sought the help of OSU’s Marine Mammal Institute to confirm that each of the samples in that study had come from a different whale.

Yet while carrying out this fairly routine analysis, Alexander stumbled upon signs of Eve’s intriguing genetic legacy.

“Previous papers had suggested that sperm whales maybe had low mitochondrial diversity,” Alexander says. But her assumption had been that this low diversity was an accidental side-effect of not having enough data. Read more...