Million-year-old genome extracted from mammoth teeth is 'oldest ancient DNA on record'

The mammoth teeth which have been preserved in Eastern Siberian permafrost have now produced the oldest ancient DNA on record. The findings which were published in the journal Nature on February 17, indicate that the million-year-old genome is here. A new type of mammoth has been identified from the genomic DNA which was extracted from a trio of tooth specimens. This further gave rise to a North American species. 

Studying ancient samples 

As per the researchers, ancient DNA could only survive beyond one million years if the right sample could be discovered. They explained that after an organism dies, its chromosomes shatter into pieces. With time, the DNA strands become so small that no information can be extracted out of them. 

According to the reports by Nature, Ludovic Orlando, an ancient-DNA specialist at the Centre for Anthropobiology and Genomics of Toulouse in France said that he loved paper as he had been waiting for it for more than eight years now. Orlando co-led a 2013 study which sequenced the previous oldest ancient DNA. This was a genome from a 560,000-to-780,000-year-old horse leg bone. He further said that he is pleased to lose this record as it was a heavy one.

"From tiny amounts of DNA remaining in the sample [we can] actually make quite large inferences about the evolution and demographic history of these mammoth specimens," he said.

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Orlando’s team was responsible for discovering that fragments as short as 25 DNA letters in their horse bone could be interpreted. These fragments were from the Canadian Yukon Territory. The recently discovered fragments, which are million-year-old remains preserved in the constant cold of permafrost, are also expected to contain NA fragments of that length. However, Orlando raises a doubt as he says if such samples exist. 

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Love Dalén, an evolutionary geneticist at the Swedish Museum of Natural History (SMNH) in Stockholm, has been loitering with the idea of since the year 2007, when he first encountered a collection of them. The samples which have been sequenced by his team had been excavated by the Russian palaeontologist Andrei Sher. He says that it's not always true that everything which has been found in permafrost will work. 

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