Ancient DNA Show Possible Migration

An article in National Geographic discusses some interesting information found in the DNA of early humans in southern Europe. Population geneticists have found that in the Iberian Peninsula area a migration that occurred roughly 4500 years ago had a drastic impact of the genetics of the people there. By sequencing the DNA of 271 ancient Iberians they found out that around 2500 B.C. there was the appearance of individuals from the Black and Caspian sea area which caused a change in the DNA of the population by about 40 percent. They also found that by 2000 B.C. the Y chromosome was completely changed, meaning that the migration that took place earlier consisted largely of men. Researchers believe that these men might have helped to usher in the Bronze Age in that area. There was also the skeleton of a single North African individual found in the Iberian area from about 2500 B.C. who shows that there was movement between North Africa and the Iberian Peninsula earlier than they believed.

I think that the information that was discussed in this article was interesting because there is so much about our early human ancestors that we don’t know so any information that we can get can be rather fascinating. I also think it’s interesting how we can sequence the DNA of people back then, and how what we can find from this DNA can inform us about things like migration patterns from the Russia area to Europe, and what kind people might was traveled in this migration.    

Ancient Humans May Have Left Genetic Mark In Neanderthals' DNA

Scientists found the first scrap of Neanderthal DNA in a fossil in 1997. Since this discovery, they have recovered genetic material, even entire genomes, from a number of neanderthal bones. These investigations have yielded the remarkable surprise: 1 to 2 percent of the DNA in non-African people comes from Neanderthals. 

This genetic legacy is the result of interbreeding about 50,000 years ago between Neanderthals and the common ancestors of Europeans and Asians. Recent studies even suggest that human health today is influenced by Neanderthal genes, contributing to conditions from allergies to depression. 

Now, scientists have found that genes have flowed both ways. In a study published on Nature, scientists reported that another instance of interbreeding left Neanderthals in Siberia with chunks of human DNA. This exchange seems to have taken place 100,000 years ago. This is confusing, because evidence indicates the ancestors of todays non-Africans did not expand out of Africa until roughly 55,000 years ago. Thus, it is possible that these Neanderthals acquired DNA from a mysterious early migration of humans. 

Humans and Neanderthals split from a common ancestor in Africa around 600,000 years ago. At some point after this, the ancestors of Neanderthals spread to Europe, the Middle East and Central Asia. Along the way, Neanderthals took on the stocky anatomy we are all familiar with. The last Neanderthals appear to have died around 40,000 years ago. 

Scientists Dr. Siepel and Dr. Castellano found an unexpected example of so-called gene flow: the Altai Neanderthals shared some mutations with living Africans, but not Europeans or Asians. This pattern suggests that an African lineage of humans interbred with the Altai ancestors, after they split from Neanderthals. They came to the conclusion that when DNA gets passed down generation to generation, it gets shuffled into new arrangements, which can be built into some sort of timeline. Thus, scientists estimated that humans and the ancestors of Altai Neanderthals interbred about 100,000 years ago - way before people were thought to have left Africa. 

I believe this information throws a wrench in many previous findings and understandings about Neanderthal interbreeding. But, like many other scientific data, new findings alter beliefs every single day. I always believed that Neanderthals simply interbred with human ancestors to make the humans on Earth today, but I never realized that Neanderthals could possibly have human DNA. It is hard to imagine, because this must have happened before non-Africans expanded out of Africa, therefore the Neanderthals must have acquired human DNA from a mysterious early migration of humans. It is amazing how DNA mutations can serve as a timeline, and solve many genetic mysteries. 

Scientists Recover First Genome of Ancient Human

On October 8, 2015, a group of scientists recovered the first genome of an ancient human from Ethiopia. The DNA from the Ethiopian human is shockingly different than that of current day Africans still residing in the country.  Because the DNA is so different, scientists concluded that an ancient human had migrated from the vast East and that the group of humans had been scattered across the continent. The place where the fossil was found implies Eurasian Migration in ancient times. Joseph Prickell, an ancient DNA expert from the New York Genome Center says that this discovery "is a major milestone for the field." 

For years, scientists had doubted that any DNA could be recovered from ancient remains, but with this finding, there is hope that much older remains can have DNA extracted from them. Few scientists thought it possible to extract DNA from a fossil due to the fact that all other remains would quickly be wiped out by bacteria and fungi. In many cases, scientists were unable to retrieve any DNA at all from ancient humans. The conditions in which many fossils were found were in the tropic, where the moist environment would also contribute to the wiping out of any genetic materials. However, in recent years, it was discovered that ear bones preserve their genetic material even when all other bones have lost theirs.

This could potentially mean that there could be more humanoid and ancient human DNA discoveries if fossils are to be found intact. This gives hope for the field, and may provide some insight on more specifics when it comes to the sequence in which macroevolution occurred. Hopefully this will become another stepping stone in science's explanation of macroevolution and will also provide more evidence on how a species can change over long periods of time. I believe this genome will allow scientists to understand the way genes can mutate and change and will additionally help scientists to understand how much genetic variation had to occur in order to get to the current human genome. 

The original article can be found here. 

An article on the potential Eurasian migration can be found here.