Although Neanderthals have been extinct for about 30,000 years, Neanderthal genes still manifest in today’s modern human beings. But it isn’t exactly in a good way, as it’s those genes that may make us more likely to catch specific diseases.
A report from The Verge focused on a study published earlier in the week in the journal Cell, which talks about a phenomenon known as regulation of gene expression. This term refers to how the DNA we have inherited from Neanderthals can affect such variables in modern humans. These variables may include our height, as well as how likely we are to develop diseases such as lupus or schizophrenia. According to the researchers, people with Neanderthal genes may be more likely than others to get the above diseases and others.
The new research comes three years after two separate papers had suggested that approximately one to four percent of our DNA had come from Neanderthals. The Smithsonian wrote in 2014 that the researchers behind the two studies used different approaches, yet came up with the same conclusion – modern humans still have a tiny little bit of Neanderthal in them.
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A report from Scientific American detailing one of the early-2014 studies stressed that today’s humans received a mixed bag from their Neanderthal ancestors. On the plus side, having Neanderthal genes allowed people to adapt easier to new environments, but on the negative side, this made people more susceptible to certain diseases.
“Those genes with the highest Neanderthal ancestry are associated with keratin, a protein found in skin and hair. The Neanderthal variants of these genes may well have helped early modern humans adapt to the new environments they found themselves in as they spread into Eurasia. But the researchers also found that people today carry Neanderthal genes that are associated with diseases including Crohn’s, type 2 diabetes and lupus.”
Going back to the present study, co-author Joshua Akey, a geneticist at the University of Washington, said that Neanderthal genes had a “pervasive” effect on us. His team used genetic data from tissues, as opposed to medical records, and went into the intricate process of determining which genes are “turned on or off” in today’s humans.
Based on the analysis of 52 different tissues, all but two of them had any preference for human or Neanderthal gene expression – the only exceptions were the brains and the testes. The gene expression in both those tissues wasn’t as strong as it was in other tissues, and the researchers believe that this may be because they both evolved much faster than other body parts did.
“If we understand the Neanderthal genome and its function better, then we’ll understand the human genome and its function better,” Akey commented to The Verge.
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A separate and newer report from the Smithsonian adds that there were differences in human and Neanderthal gene expression in 25 percent of the tissues tested. Some of the differences resulted in a better chance of people becoming taller, but others had, as mentioned above, made them more likely to contract lupus or develop schizophrenia.
Tony Capra, a Vanderbilt University geneticist who wasn’t involved in the study, was quoted as saying the lack of gene expression in the testes may have compromised fertility when Neanderthals and ancient humans began to interbreed.
“It further illustrates that Neanderthal DNA that remains in modern humans has the potential to influence diverse traits.”
Following these new and revealing takeaways from their study of modern human and Neanderthal genes, the researchers are hoping to study gene expression in people of Melanesian descent, due to the fact they have gene sequences inherited from the Denisovans. Akey added to The Verge that he wants to study more geographically diverse populations, and that these research projects may potentially yield the discovery of new groups of early humans.
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