Lots of people (including myself) have been using DNA to trace their genetic lineage, and it’s certainly the most reliable method. Scientists who study the origins of the human species have also done this on much rarer samples, from the traces of DNA they can find in fossils from hundreds of thousands of years ago. They have been able to find and analyze traces of DNA from Neanderthals and Denisovans, and to show that modern humans also carry DNA from these extinct kindred species.
However, DNA has its limits. It’s a delicate molecule and will fall apart rather quickly under most conditions. The furthest back anybody has been able to go with ancient DNA analysis is about 500,000 year ago. This is unfortunate because the origins of our relationships to those other kindred species lie over that 500,000 year horizon.
However, there are other biological molecules that are more durable: proteins. These are versatile molecules with many jobs to do in living systems. It is possible to sequence the amino acids that make up the proteins and then compare the sequences to those of other species to see how similar they are. The amino acid sequence ultimately codes back to the DNA that made it, so it’s a second-hand record of the DNA.
Scientists have managed to perform such an analysis on proteins extracted from an 800,000 year old tooth from a species that lived in northern Spain called Homo antecessor. Before this analysis, H. antecessor was claimed to be the ancestor to Neanderthals, Denisovans, and us (Homo sapiens) as well, on the basis of its modern-looking facial features. The protein analysis backs this up. As Enrico Cappellini, a geneticist at the University of Copenhagen’s Natural History Museum of Denmark, explains, “We see that antecessor falls as a sister group—close, very close—to the branch that leads to us.”
So an new technique has arisen to allow the remaining ancient molecules of biology to tell us something about that long-ago world.
And now, what you’ve really come here for, let’s take a look at the comments below the fold. But first, a word from our sponsors:
Here at Top Comments we welcome longtime as well as brand new Daily Kos readers to join us at 10pm Eastern. We strive to nourish community by rounding up some of the site's best, funniest, most mojo'd & most informative commentary, and we depend on your help!! If you see a comment by another Kossack that deserves wider recognition, please send it either to topcomments at gmail or to the Top Comments group mailbox by 9:30pm Eastern. Pleaseplease please include a few words about why you sent it in as well as your user name (even if you think we know it already :-)), so we can credit you with the find!
Top Comments (April 2, 2020):
From Paul A:
I nominate Pool House Doctor's comment in Joan McCarter's diary as noting that the current situation -- "brought to you by the Republican party" -- is worse than war profiteering.
War profiteering is about as low as you can go. And this is definitely a war. And we are losing.
Top Mojo (April 1, 2020):
Top Mojo is courtesy of mik! Click here for more on how Top Mojo works.
Top Photos (April 1, 2020):
Thanks to jotter!