Bison bone 390.
(photo credit: PLoS ONE)
Thirty-thousand-year-old bison bones discovered in permafrost at a
Canadian goldmine are helping scientists unravel the mystery about how animals
adapt to rapid environmental change.
The bones play a key role in a
world-first study, led by University of Adelaide researchers, which analyses
special genetic modifications that turn genes on and off, without altering the
DNA sequence itself. These 'epigenetic' changes can occur rapidly between
generations – without requiring the time for standard evolutionary
Such epigenetic modifications could explain how animal species
are able to respond to rapid climate change.
In a collaboration between
the University of Adelaide's Australian Centre for Ancient DNA (ACAD) and
Sydney's Victor Chang Cardiac Research Institute, researchers have shown that it
is possible to accurately measure epigenetic modifications in extinct animals
The team of researchers measured epigenetic
modifications in 30,000-year-old permafrost bones from the Yukon region in
Canada, and compared them to those in modern-day cattle, and a 30-year-old
mummified cow from New Zealand.
Project leader Professor Alan Cooper,
Director of ACAD, says: "Epigenetics is challenging some of our standard views
of evolutionary adaptation, and the way we think about how animals use and
inherit their DNA. In theory, such systems would be invaluable for a wide range
of rapid evolutionary adaptation but it has not been possible to measure how or
whether they are used in nature, or over evolutionary timescales." Epigenetics
specialist and co-investigator Dr Catherine Suter, from the Victor Chang
Institute, has been studying the role of epigenetics in adaptation in laboratory
animals. She jumped at the chance to test epigenetic methods in ancient DNA,
which had never previously been attempted.
"This is the first step
towards testing the idea that epigenetics has driven evolution in natural
populations," Dr Suter says.
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Professor Cooper says: "The climate record
shows that very rapid change has been a persistent feature of the recent past,
and organisms would need to adapt to these changes in their environment equally
quickly. Standard mutation and selection processes are likely to be too slow in
many of these situations."
"Standard genetic tests do not detect epigenetic
changes, because the actual DNA sequence is the same," says lead author, ACAD
senior researcher Bastien Llamas, an Australian Research Council (ARC) Fellow.
"However, we were able to use special methods to show that epigenetic sites in
this extinct species were comparable to modern cattle.
"There is growing
interest in the potential evolutionary role of epigenetic changes, but to truly
demonstrate this will require studies of past populations as they experience
major environmental changes," he says.This work has been published in
the online peer-reviewed journal PLoS ONE.This article was first published at www.newswise.com
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