Wednesday, March 30, 2011

The secret sex life of the Amoeba

Image: Ameoba, caught in the act

After taking a second look at the tree of life, researchers are rethinking the asexuality of amoebas, considered the epitome of chastity. They now have evidence of amoeboid sex lives, suggesting the act didn't evolve, it has always been there.

Amoebas are blob-like creatures about a billion years old ­— the oldest members of the domain of life called the eukaryotes. This group is fundamentally different in appearance and various other features from the two other domains of life. Amoeba species are spread throughout this tree on every branch, interspersed with familiar lineages like animals and plants. They are known for how they move, slowly extending foot-like portions of their cell membranes.

"It changes how we interpret the evolution of organisms," study researcher Daniel Lahr, of the University of Massachusetts, told LiveScience. "If the last common ancestor of eukaryotes was sexual, then there is in practice no evolution of sex."

By taking a sweeping look at what we know about them by searching through the scientific literature, the researchers say those amoebas are more sexually active than we think.

"When discussing the sex of amoeboid protists, the existing evidence does not evoke chastity but rather Kama Sutra," Lahr writes in the paper, published in the March 23 issue of the journal Proceedings of the Royal Society B: Biological Sciences.  ...

Amoeba sex might have been missed because when grown in the lab, many of them don't show any signs of engaging in sex — they have the ability to reproduce themselves by cloning, or copying themselves, indefinitely. And when they did show signs of sex, researchers may have mistaken it for a rare exception to the no-sex rule. ...

via Amoebas: Sexier than anyone knew - Technology & science - Science - LiveScience -

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