Steiper of Hunter College of the City University of New York and his colleagues first consulted the latest fossil evidence to estimate that the human evolutionary family separated from chimps' ancestors between 6 million and 7 million years ago, while the macaque monkey lineage diverged from
its baboon ancestors between 5 million and 7 million years ago.
falciparum's molecular clock has been ticking for at least 300,000 years since its various populations diverged from
a common progenitor.
The sounds differ so much, he says, that he now suspects they evolved only after the lineage of river dolphins diverged from
Previous research had indicated that the long arm derives from an early evolutionary form of the X chromosome and that the short arm was added at some point after marsupials diverged from
mammals that form a placenta to support a fetus.
coli's 4,288 genes were introduced into the bacterium from other microbes in the 100 million years since it diverged from
the lineage it shares with Salmonella.
One and a half billion years after plants' lineage diverged from
ours, our green cousins are finally receiving the credit they deserve.
Studies of the only other two monotreme species had suggested that the animals don't have REM sleep, implying that it evolved after monotremes diverged from
the other two mammalian branches, marsupials and placentals.
Invertebrates diverged from
chordates-the phylum to which vertebrates belong-about a billion years ago.
They next calculated the rate at which these random genetic variations occurred, based on estimates that the tribes diverged from
a single group between 8,000 and 10,000 years ago.