Published Monday 31
January 2011 | Christina Troelsen - Researchers
at Aarhus University are part of an international
group that has analysed the orang-utan genome
for the first time ever. The research results
are featured on the front cover of the internationally
recognised journal Nature, and they provide
new knowledge about this common ancestor
to all primates.
Front cover of Nature, 27 January 2011
On Thursday 27 January, the first analysis
of the complete orang-utan genome was published
in the journal Nature. The orang-utan is
only the third primate after humans and
chimpanzees to have its complete genome
sequenced. The people behind this research
include a group of scientists at Aarhus
University who discovered by means of a
major genetic archaeology study that one
per cent of our genome has more in common
with the orang-utan than we previously believed.
By analysing DNA sequences
from humans, chimpanzees and orang-utans,
the researchers also gained insight into
how mankind has developed since the time
when the common ancestor to all primates
roamed the Earth.
Genetic archaeology
The genetic variation we observe in humans
or chimpanzees today is relatively new,
and it can therefore only tell us about
human development in the last one million
years approximately, and not about our development
in the previous millions of years.
However, the Aarhus
researchers have developed methods for analysing
‘extinct’ genetic variation, and this was
an enormous step forward for their research.
“The genetic variation in the ancestor of
humans and chimpanzees disappeared long
ago and was replaced by a new variation
in them both,” explains Associate Professor
Thomas Mailund, Bioinformatics Research
Centre. “However, the variation found before
the two species split up has left signals
in our DNA that can be decoded and tell
us about our past,” he adds.
Professor Mikkel Schierup,
Department of Biological Sciences and Bioinformatics
Research Centre, elaborates: “If we look
at our total genome, it consists of a number
of different genes, and each one has a slightly
different evolutionary history than the
others. Based on the variation in gene histories,
we can form a picture of the variation in
the species that came before humans, chimpanzees
and orang-utans.”
A complicated relationship
The fact that different parts of our genome
have different histories is not controversial,
but the Aarhus researchers were nevertheless
surprised to discover that we have more
in common with the orang-utans than previously
thought. The new studies show that approximately
one per cent of our genome does not include
humans and chimpanzees as the closest relatives.
Instead, either mankind is most closely
related to the orang-utan or the chimpanzee
is.
By means of their analysis
of gene histories, the researchers can also
say that humans and orang-utans actually
separated as species about 12 million years
ago.
Contact
The Aarhus researchers are Thomas Mailund,
Asger Hobolth and Mikkel Heide Schierup,
all of whom work at the Bioinformatics Research
Centre (BiRC), Aarhus University. They can
be contacted via Thomas Mailund (mailund@birc.au.dk)
or Mikkel Schierup (mheide@birc.au.dk).
References
Comparative and demographic analysis of
orang-utan genomes The International Orangutan
Genome Sequencing and Analysis Consortium.
Nature 2011.
Incomplete lineage sorting patterns among
human, chimpanzee, and orangutan suggest
recent orangutan speciation and widespread
selection A. Hobolth, J.Y. Dutheil, J. Hawks,
M.H. Schierup and T. Mailund. Genome Research
2011
Thank You
