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Language: en
scientists announced they sequenced the
oldest DNA to date two million year old
DNA found in Greenland revealing an
ancient ecosystem unlike anything
existing today finding DNA in the Deep
time context is amazing it's really
important for for how this field is
going to advance it's really the most
remarkable new thing
since I've been working in this area
the movie Jurassic Park made the idea of
recovering old DNA popular
but successfully sequencing really
ancient DNA has proved elusive the irony
is that in 2005 I did a review paper and
I said well it's it's not possible that
DNA can survive more than one million
years right the latest work by eska
willerslev and his team extends the
record of ancient DNA by about another
million years
Define the DNA researchers drilled in
the capcover Haven formation in
Greenland to collect soil samples they
found evidence of ancient living things
including horseshoe crabs caribou and
even Mastodon using DNA found in soil
every single cell
contains DNA if a mastodon urinates or
put feces on the ground you know its DNA
you can't identify it after you know
some time but the DNA Will Survive it's
likely that the ancient DNA was uniquely
preserved by a combination of the cold
and some minerals in the two million
year old sediment DNA is electrically
charged and many sediment particles are
also electrically charged
so certain sediment particles such as
clay will bind DNA I mean the DNA will
basically stick to it The Binding
basically protects the DNA from the
enzymes that would otherwise chop it up
that Bond may have kept that DNA intact
for far longer than scientists including
willerslev had thought possible but to
retrieve the DNA from the soil and
separate it from everything else in it
required state-of-the-art technology and
techniques developed over many years of
trial and error I mean I don't even know
how to describe it right I mean you have
been sitting working on something for 15
years that doesn't work and certainly it
does a breakthrough it's like
oh my God right sounds very boring to
many people at first but this is the
fundamental thing that changes
everything
suddenly you can have samples that you
thought had no DNA at all it turns out
they did have DNA but it's stuck and all
you're doing is releasing it
next challenge was to compare the DNA to
vast libraries of all other known DNA to
identify close relatives
the plants and animals they found in
this ancient ecosystem do not exist
together today so for example we find
horseshoe prep which is a crab that is
found way way to the South today and
also suggests that the ocean at that
time was way warmer than what we see
today unlike the polar desert that
exists here today this Force ecosystem
could have been considerably warmer but
like Greenland today existed in extreme
seasonality months of Summer Sun in
complete darkness in the winter months
I think that's really stunning still
stunning to me to think of how warm it
is and that you have life over time that
has adapted to the extreme seasonality
understanding the lineage of these
ancient living things could help
researchers understand how those that
exist today evolved and how they might
adapt to a changing climate if it works
it's going to change everything for us
in terms of thinking about how
ecosystems respond to climate change all
of this is like building blocks you've
got one building block you don't know
how to structure you've got two and you
still don't have a structure you have 10
and you can start building something