Extinct mammoth DNA decoded

[Allan Edels <edels@msn.com>]

Not dinosaurian, but interesting nonetheless.

> From BBC News:
http://news.bbc.co.uk/2/hi/science/nature/4535190.stm

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Extinct mammoth DNA decoded

By Helen Briggs
BBC News science reporter


Scientists have pieced together part of the genetic recipe of the extinct 
woolly mammoth.

The 5,000 DNA letters spell out the genetic code of its mitochondria, the 
structures in the cell that generate energy.

The research, published in the online edition of Nature, gives an insight 
into the elephant family tree.

It shows that the mammoth was most closely related to the Asian rather than 
the African elephant.

The three groups split from a common ancestor about six million years ago, 
with Asian elephants and mammoths diverging about half a million years 
later.

"We have finally resolved the phylogeny of the mammoth which has been 
controversial for the last 10 years," lead author Michael Hofreiter of the 
Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told 
the BBC News website.

Ice age wanderer

Mammoths lived in Africa, Europe, Asia and North America between about 1.6 
million years ago and 10,000 years ago during the Pleistocene epoch.

The woolly mammoth, Mammuthus primigenius, with its covering of shaggy hair, 
was adapted to the extremes of the ice ages.

The DNA of several extinct ice age mammals, preserved in permafrost, has 
been analysed before, but not in such detail.

"It is the longest stretch of DNA [decoded to date] from any Pleistocene 
species," said Professor Hofreiter.

Maternal line

The team of researchers - from Germany, the UK, and the US - extracted and 
analysed mammoth DNA using a new technique that works on even the tiny 
quantities of fossilised bone - in this case 200 milligrams.

Some 46 chunks of DNA sequence were matched up and arranged in order, giving 
a complete record of the mammoth's mitochondrial DNA - the circular scrap of 
genetic material found outside the cell's nucleus.

It is passed down the maternal line with small but regular changes, giving 
scientists a window into the past.

Although the bulk of an animal's genetic information is found in the 
nucleus, mitochondrial DNA is particularly useful for studying the 
evolutionary relationships between different species.

The complete mitochondrial DNA of an extinct animal has been sequenced 
before but only for the flightless bird, the moa, which died out about 500 
years ago.

Dan Bradley, an expert in ancient DNA at Trinity College, Dublin, Ireland, 
said the research was "a bit of a landmark".

"Most ancient mitochondrial DNA projects use just small parts of the 
mitochondria," he said.

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Allan Edels