BEIJING, June 8 (Xinhuanet) -- Scientists have found it was a combination of genetics and human hunters that brought about the extinction of the woolly mammoth about 12,000 years ago, near the end of the last ice age.

    For years, scientists suspected ancient human tribes hunted the mammoths and other ice age giants to oblivion. Recent research seems to contradict this notion.

    DNA lifted from wooly mammoth bones, tusks and teeth now reveals the extinction of those giants was not "a sudden event at the end of the last ice age, but a piecemeal process over tens of thousands of years involving progressive loss of genetic diversity," said University of London evolutionary biologist Ian Barnes.

    The researchers analyzed 96 mammoth samples that often came as a result of gold mining in Alaska or paleontological digs in Siberia or Europe. The team's analyses suggest woolly mammoth populations remained mostly constant in size for their last 70,000 years.

    However, occasional drops in population size led to gradual reductions in genetic diversity, findings detailed in the June 19 issue of the journal Current Biology.

    "The fact that they were not genetically diverse might have meant they were not very adaptable to climate change or disease," Barnes told LiveScience. "Maybe when the climate changed and warmed up, things became wetter, and boggy ground doesn't suit mammoths too well. Then humans might have killed off the small, remaining terminal populations."

    The fact that mammoths seemed to hang in there for tens of thousands of years with fairly low genetic diversity, not really expanding much in population size, "could be interpreted as having implications for modern elephant conservation," Barnes said. "Perhaps all the elephant family are able to exist for long periods with low genetic diversity and at a constant population size."

    "However, I would be extremely cautious about going down this route, as we don't really have enough data to extrapolate in that way, and modern elephants have human predation to deal with in a way that mammoth didn't for most of their history," Barnes cautioned.

    (Agencies)