Some tens of thousands of years ago, there were at least three separate human species sharing the planet. Beside us (Homo Sapiens) there were Neanderthals, and also the less well known Denisovans. While the Denisovans were discovered only quite recently, the Neanderthals were discovered in the mid-19th Century, and there are many specimens. As such, the Neanderthal genome was catalogued in 2011, only 11 years after the human genome. How different are they? Given that Neanderthals and Denisovans are now extinct, what features of the human genome may have given us an advantage?
Two scientists at the University of California at San Diego, Cleber Trujillo and Alysson Muotri, decided to study these questions by focusing specifically on the differences in the genomes of humans and Neanderthals. It turns out that there were only 61 differences between us and them—not many at all. Muotri, who studies the molecular biology of the brain, was most interested in differences that could effect brain development. He found such a variation in a gene called NOVA1. The corresponding NOVA1 genes of Neanderthals and humans differed by just one base pair. What difference would that make?
Using CRISPR, the Neanderthal NOVA1 gene was spliced into a human DNA, and the DNA were induced to form brain organoids, specifically cortical tissue.. The resulting organelles behaved quite differently from normal human cortical tissue. In shape, the Neanderthal gene formed cortical organoids that were not smoothly spherical, as is typical of modern humans, but more textured, like popcorn. Second, the neurons the organoids became active much earlier than the normal human ones. This behavior is similar to that of apes, such as chimps, whose newborns are more active than humans, and can move around on their own much earlier than human infants. In humans, neural activity is suppressed as the brain continues to develop while the infant is entirely dependent on his or her parents for survival. The price for the delay in neural activity is the ability for more sophisticated thought and communication in adulthood.
(On the other hand, after observing the human activity on January 6 of this year at the capital, one has to wonder exactly how sophisticated this really is.)
On to the comments below the fold, but first, we have a word from our sponsor:
Here at Top Comments 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. Please please 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 (February 11, 2021):
Highlighted by Mentha:
This comment by marsanges in the Daily Bucket post by funningforrest.
Top Mojo (February 10, 2021):
Top Mojo is courtesy of mik! Click here for more on how Top Mojo works.
Top Photos (February 10, 2021):
Tonight’s picture quilt is courtesy of jotter!
