In the New York Times they wrote about a team of Paleo-geneticist and evolutionary biologist were able to sequence the oldest DNA now on record. The previous oldest DNA that was sequenced was 700,000 years old from a horse specimen but one of the 3 mammoths’ fossils that had its DNA extracted and sequenced was 1.2 million years old! the fossils that were retrieved were believed to be that of the Columbian mammoth, this is a species that roamed what is modern day north America. The way that the DNA was extracted from the mammoth was from the molars of each fossils. The molars were described as big as milk cartoons which is a huge tooth. theses molars were drilled into and the material collected were then treated various chemicals and enzymes followed by a washing protocol which isolated the DNA base pairs from each fossil.
After the DNA base pairs was extracted, they
then had to decontaminate it since there are other base pairs from plants,
bacteria, and even some humane DNA mixed in with the mammoth’s fossil over
time. They then used the DNA of an African Elephant, who is a close descendant
of the mammoth, to weed through all the non-mammoth DNA. They were able to use
the African elephant’s DNA to match up similar base pairs, they then used it to
put the 49 million-3.7 Billion based pairs that were collected from the fossils
in the correct order making the DNA fully sequenced. This is now the oldest DNA
sequenced, this shows great promise to future studies of the animal and
so many
other species since sequencing older DNA is becoming more of a reality.
This also helped the researchers discover that
the once singular evolutionary tree of the Columbian mammoth is no longer
singular, the team realized the oldest DNA was different from the 2 other
Columbian mammoths DNA sequences. The DNA was similar but different enough to
allow the team of researchers to see that the 3 fossils were related but the
oldest sequence was different, leading them to believe it belonged to a
previously unknown lineage of mammoth. It was previously thought that there was
a single lineage of mammoth in Siberia that gave rise to the woolly mammoth and
then the Columbian mammoth. However, it turns out that the Columbian mammoth is
a hybrid of this new linage and the woolly mammoth. This would have never been
discovered without the sequencing of this 1.2-million-year-old DNA. This opens
research in a new lineage that they never knew about, allowing them to start to
understand how it lived in the past.
Sources:
https://www.nytimes.com/2021/02/17/science/DNA-mammoth.html
https://www.nature.com/articles/d41586-021-00436-x
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Catchy title. Imposing pictures of mammoth teeth and mammoths. The new science from the very old DNA is quite well outlined. The note on the possibility of engendering a mammoth from the old DNA is tantalizing. Leaving it to the end ties into your title and gets the reader to read the whole thing.
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