A
hairy relative of elephants
Woolly mammoths
were a species of elephant that populated much of Eurasia
and North America until about 10,000 years ago. Along
with their living relatives, the African and Indian elephant
species, mammoths originated in Africa millions of years ago.
Within the last several hundred thousand years, mammoths
adapted to the numerous ice age periods in the northern
hemisphere by evolving several traits that are specific
to woolly mammoths. These traits include the shape and size of
their bodies, the thick hair coat, the enormous tusks,
and a 2-inch layer of insulating fat tissue.
Lessons
from the mammoth genome
The Mammoth
Genome Project discussed here is the first to decipher
the genome of an extinct animal. Our data allow a view
back in time as far as 60,000 years and describe the genetic
changes that occurred in mammoths. Our analyses show that
the rate of evolution within the three lineages of elephants
(mammoth, Indian elephant and African elephant) since
they separated about 6 million years ago is only half
of that between humans and chimpanzees. Our study also
identified changes in proteins that occurred only in mammoths,
but not in any of the other 50 mammalian genomes sequenced
so far. Since proteins are a main contributor to an animal's physical
traits, it is possible that these differences
helped mammoths to survive in their harsh environment.
Biology
of extinction
The broader
implications of our research involve studying
genomes of extinct animals and asking specific questions
about their life styles. In general, our work shows that
it is possible to open a window to the past and study
animals that are long gone at the same level of genetic
detail as when examining modern species. The lessons being
learned from studying extinct species can help us to understand
the processes that are driving today's endangered species
toward possible extinction.
The
Center for Comparative Genomics and Bioinformatics
The Mammoth
Genome Project is being conducted at the Center for Comparative
Genomics and Bioinformatics at the Pennsylvania State
University. The team has already completed a first phase
of the project, where the genome was read at single-fold
coverage. We are currently working on a high-resolution
sequence of the genome, which has more than 4 billion
base pairs.
This web site
contains information about the on-going Mammoth Genome
Project.
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