Ancient DNA traces the woolly mammoth's disappearanceSome ancient-DNA evidence has offered new clues to a very cold case: the disappearance of the last woolly mammoths, one of the most iconic of all Ice Age giants, according to a June 7th report published online in Current Biology. DNA lifted from the bones, teeth, and tusks of the extinct mammoths revealed a “genetic signature” of a range expansion after the last interglacial period. After the mammoths’ migration, the population apparently leveled off, and one of two lineages died out. “In combination with the results on other species, a picture is emerging of...