So this is really cool.
What we've just found you can see is one, two, three, four, pieces of mammoth bone here.
See these pieces are actually still frozen in the permafrost we can't get them out at all.
Which means they're going to be really well preserved.
Just heard that big splash of water back there
that means another hole's broken through. Here comes the water we better get out of here
Beth Shapiro came to genomics through an interest in glaciers,
ecosystems, and massive changes in climate over time.
I was super interested in the traces of the glaciers that had extended across the continent,
and really thought that it would be amazing if we could understand
how that large-scale habitat shift had impacted ecosystems.
This was in the early days of a new field called ancient DNA.
Okay.
It had only just been discovered that DNA is preserved in the remains of organisms after they die,
and it was just an amazing coincidence of opportunities.
I ended up at Oxford University where one of the earliest ancient DNA labs was, and had an opportunity to join this field.
I actually had no experience at all in molecular biology at the time.
In the early days we could only access DNA using PCR.
Which meant that we needed to find relatively long fragments of intact preserved DNA.
It was really with the advent of next generation sequencing technologies,
where we could target and recover even the tiniest shortest most broken fragments of DNA.
Fragments that were as short as 25 or 30 bases long.
That we could really start to do population genetics at scale.
With sequencing technologies Beth was able to analyze enough data
to work with older and less intact DNA samples going further and further back in time.
We had a mammoth fossil from Siberia
and we extracted DNA from this mammoth fossil and we learned
by comparing each one of those tiny fragments of DNA
to the online database of all the fragments of DNA that have ever been published,
that only about half of the DNA that we were recovering was mammoth DNA.
The other half was things like bacteria or microbes other other fungi that are that are in the ecosystem.
We were super disappointed we thought oh no it's actually going to take us so much more sequencing to get a whole mammoth genome.
In fact what we now know is that was an exceptionally well preserved specimen.
That most of the specimens that we work with have very little DNA that is endogenous to that animal.
Gathering ancient DNA provides a unique insight into climatic and ecological systems of the past,
giving scientists like Beth a new window into human evolution.
We now have genome-wide data from hundreds of human remains from archaeological sites from
across the world and this has really allowed us to begin to understand
the fine scale picture of how humans moved across the world how populations interacted
with each other how environmental changes and the neolithic, the use of domestic animals and plants
really changed our lineage helped us to adapt to become what we are today.
Comparing the genomes of modern and archaic humans
has also led to a deeper understanding of what makes us different from our ancient cousins.
Well we've done some work using the neanderthal and denisovan genomes to
compare all the genomes that are there and ask
"are there regions of the genome where all humans share variants?"
We've managed to narrow this down to actually a really small portion of the genome,
where where humans share some adaptive change everybody has an adaptive change
that neanderthals don't and the next phase of research in human evolution is really i think going to
focus in part on these mutations because these are the clues to what it is that makes us human.
Big questions to answer with old bones.
But Beth started on this road motivated by understanding the challenges of climate change.
Can paleogenomics inform conservation?
The past, one can think of as a completed evolutionary experiment.
If we want to understand what happened during a period of rapid global warming
we only have to look as far back as about 10 to 15 000 years ago
when the planet went through an extremely rapid warming event out of the last ice age.
And this rapid warming event was associated with mass extinctions with reshuffling of ecosystems and communities,
and it would be great if we could use ancient DNA from the whole ecosystem,
not just individual species but also from the plants and the microbes,
to be able to better understand what it is that makes some communities more resilient in the face of this type of rapid climate change.
From those first glimmers in frozen bones, ancient genomics has exploded into a thriving field,
as new technology makes it possible to ask deeper questions about where we came from and where we are headed.
Recently there's been a rapid development of technologies
to just get a piece of dirt, either from a core that you stick into a lake,
or cores that you stick into frozen dirt or even just going and collecting sediments from the bottoms of caves.
And being able to recover even population level information just from DNA in that bit of dirt,
and this is an amazing resource for looking at the entire community
not just the individual whose bone happened to be preserved,
but the plants and the animals and the microbes everything that was interacting to make that community what it was.
This is how we're really going to begin to get insights into what allows these ecosystems to be more resilient.
These insights that will be helpful as we begin to make
more informed decisions about how to protect and preserve ecosystems in the present day.