Dr. David Gwynn
speaker
906 appearances
4 recordings
1 series
first heard Nov 2024
last heard 21 Dec
Dr. David Gwynn’s voice in public audio — every appearance, attributed to the second.
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You've got to figure out on a species by species basis, how are they being impacted by this whole constellation of changes that are taking place at the end of the Pleistocene? So what you have to do is figure out how are all these individual species responding to this constellation of changes that are occurring at the end of the Pleistocene? It has to be done on a species by species basis.
What are their thresholds? What are their tolerances? What happened in the environment that caused them to spiral into extinction? Here's where ancient DNA comes in. We've not been able to figure this out. You can't learn this from the fossil record when you've got a bone here and a bone there, but you can use ancient DNA to look at changes in genetic diversity.
You can use ancient DNA to measure demographic or population size changes. You can basically, if you get a DNA record through time, and this is something that we're actively working on at the Center for Geogenetics, you can measure, you can actually start to see when species begin to spiral down toward extinction.
When they begin to basically lose population, you start to see inbreeding, you start to see changes in reduction in genetic diversity. You can see that the vegetation, and this goes back to something we talked about earlier in the podcast, you can see when the vegetation that had been supporting them for tens of thousands of years is no longer around.
So with ancient DNA, we are finally going to get past the impasse that we've long had. Blaming extinctions on humans is just a kind of a simple-minded answer, and it doesn't work. It's actually hard work to figure out the link between the climate changes and the extinction of these animals. And that's work that's all in front of us, but work that's being actively done.
First Peoples in a New World, Populating Ice Age America. And it's published by Cambridge University Press. It's actually in a second edition, came out in 2021. As for all of the late breaking DNA work, well, stay tuned. Maybe if we have this conversation again in a couple, three years, we'll be able to update your listeners.
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