Neanderthals and Humans First Mated 50,000 Years Ago, DNA Reveals
Grace George
Source: Live Science
Author: Charles Q. Choi
Date Published: October 22nd, 2014
Summary: Using the shaft of a 45,000 year old thighbone discovered on a river bank in Siberia, scientists attempted to determine when Neanderthals started interbreeding with humans. It has already been theorized that humans developed Asia first by traveling a more southern, coastal route and then heading more north which gave rise to mainland Asians. They tested the bone and deemed it about 45,000 years old so they claim that it "indicates that early modern human migrations into Eurasia were not solely via a southern route as has been previously suggested," Kelso said. After reviewing the genetic analysis of DNA from the bone, it revealed that the man was closely related to present day Asians and to early Europeans. It also showed that he carried a lot of ancestral DNA of Neanderthals, so using this information, the scientists determined that interbreeding and populating of Asia began between 50,000 and 60,000. Scientists have continued examining the DNA to see how the human began to evolve once it started interbreeding and incorporating the new genes into offspring as well as the changing environments as humans explored further north and south.
Connection: In the past unit we discussed genomes which tied into chapter 14 discussing the gene pool, genetic drift, and overall- evolution. This was a large step towards the evolution of humans as we started to adventure further out into Earth and the different biomes located on it. The interbreeding also introduced a new set of genes and alleles into the human genome which then affected the offspring of generations and generations, not only with their genes, but also with how they adapted to environments, differently then humans that did not descend from Neanderthals. As we learned in 15.1, there are certain barriers that prevent interbreeding which tells us that humans and Neanderthals must have been closely related enough to be able to overcome those barriers and breed. Back, 50,000 years ago, had Neanderthals and humans not bred, modern day humans would definitely look different as evolution from new genes and environments has affected the way we have adapted over time.
How does interbreeding with Neanderthals affect the evolution of Homo sapiens, does it attribute to the variations within our species such as skin color and body structure. And if the children of Neanderthals and Homo sapiens are even able to reproduce?
ReplyDeleteWhat are some of the specific traits that differentiate modern Homo Sapiens with Neanderthals?
ReplyDeleteTo answer Michael's question, the interbreeding effected the genes in the homo sapien gene pool because once they began breeding new genes were introduced effecting how offspring would turn out. However, I am not quite sure what particular character traits the Neanderthals brought into the new gene pool but my best guess would be that evolution of homo sapiens had a lot to do with the Neanderthals adding their genes into our pool. Finally, the children were most likely able to reproduce because the only way that they could interbreed would be for them to break down the barriers between their species and as it mentions in the article, after breeding, we began to expand outward, which was mostly likely caused by a growing population, one of which Neanderthals contributed to. Also, I did read that scientists have done studies and examined homo sapiens with Neanderthal like characteristics, therefore coming to the conclusion that some of the offspring must have been able to reproduce.
ReplyDeleteTo answer Richard, there are not specific traits that differentiate between the species. Actually, according to Huffington Post and a few other websites I checked out, about 99.84% of our DNA is identical to Neanderthals, but the biggest difference is really DNA with on/off switches. The main reason that we are so different is that a lot of genes that Neanderthals have turned on, are shut off in humans, and vice versa. No specifics were really given as to traits, but by simply examining a picture, my best guess would be that hair, shape of spine, etc are characteristics that get shut on off depending on species.
ReplyDeleteWhat other ways might scientists use to establish the relationship between neanderthals and humans? Could genomic code aid in any way?
ReplyDelete