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Researchers: Woolly mammoth genes nearly identical to elephant’s
Dec. 19,
2005
Courtesy Penn State University
and World Science staff
The majestic woolly mammoth that roamed the Northern Hemisphere’s grassy plains before 10,000 years ago was 98.5 percent identical in its genes to the modern African elephant, researchers say.
The finds come from a study of mammoth bones from Siberia, conducted by researchers from McMaster University in Hamilton, Ontario, and other institutions.
The results shows that scientists are taking strides forward in
sequencing ancient DNA, traditionally a tricky field, the researchers
said. Ancient DNA tends to break up and mix with genetic material from
other organisms, complicating the work.
The team’s report on the first sequences from the genome of a woolly mammoth
is to appear in the Dec. 22 online edition of the research journal
Science.
The “breakthrough” allows for first comparisons of this species with today’s African and Indian elephants,
the researchers said.
Previously, researchers had been able to analyze some mammoth DNA, but only a
minuscule fraction, according to the team. Scientists in the past had to rely on a special type of DNA from compartments within cells called the
mitochondria. This DNA is easier to analyze because it contain 1,000 times more copies of genes than the rest of the DNA, which is in the cell nucleus. But the mitochondria
contain a tiny proportion of the full variety of the genes.
In the new study, researchers said they identified 13 million letters of genetic code from the DNA of the cell nuclei
of the mammoth, an animal some scientists believe humans may have hunted
to extinction.
The researchers said they showed that the sequence of these letters
almost matched that of African elephant DNA. That reflects the animals’
close evolutionary relationship, they added.
The project became possible through the discovery of well preserved remains in the
permafrost, or permanently frozen ground, of northern Siberia, the
researchers said. What also helped was a new high-efficiency gene sequencing technique that could cope with the heavily fragmented
ancient DNA, taken from the creature’s jaws.
The bone was about 28,000 years old, according to the scientists. They used
computer technology to show that half of the bone DNA was actually from the
mammoth—a record amount compared to past studies, they said. The rest was from microbes living in the soil.
The study shows “any organism that has been trapped in frozen ice or a permafrost environment for up to one million years will be an open book” to
science, according to a statement from Penn State University in University Park, Penn., which collaborated in the research.
The search is now on for more specimens from plant, animal, and man that can illuminate the route evolution took, and
maybe clarify the reasons for extinctions, researcher said.
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