Quote of the Day: evolving body

[timelets]

We can think of an individual body evolving within its environment:

“It occurred to Walsh that he could use the mutations to reconstruct the cell lineages of the brain—not to watch the lineages grow forward as Conklin had, but to work his way back up their branches like a genealogist, back to the womb.

Scanning the trillions of bases they sequenced, the researchers spotted hundreds of somatic mutations in each neuron. Many of the mutations were shared by some of the neurons, but not all of them. Some were found in only a few of the neurons, and some were unique to a single cell. The researchers used this pattern to draw a genealogy of the brain, linking each neuron to its close cousins and its more distant relatives. Walsh and his colleagues found that the cells belonged to five distinct lineages, the cells in each one inheriting the same distinctive mosaic signature.

A single genome can no longer define us, because our inner heredity toys with DNA, altering just about every piece of genetic material we inherit. Even in our skulls, we grow a witches’-broom."

- - Carl Zimmer. “She Has Her Mother's Laugh.”