The Results Of Research Show That The Interbreeding Of Races Between Ancient Hominids (Humans Or Primitives) Has Had A Significant Impact On Our Formation.
Genome Secrets, Scientists Have Recognized That A Small Percentage Of Dna May Give Modern Humans Unique Human Characteristics.
Genetic advances that make humans unique may be scattered in small units of DNA inherited from extinct ancestors.
Researchers at Science Advances have reported that only 1.5 to 7 percent of the human genetics manual, or genome, contains unique human DNA and is not found in other organisms.
This human-specific DNA, which is scattered throughout the genome, tends to include genes involved in brain growth and function; This shows that the evolution of the brain was important in the humanization of human beings. But researchers still do not know exactly what genes do and how these human-specific changes in DNA close to that gene may have affected brain development.
“I do not know if we will ever be able to say what exclusively makes us human,” said Emilia Verta Sanchez, a population geneticist at Brown University in Providence, USA, who did not participate in the study. We do not know that this causes us to think or behave in a certain way. “Neanderthals and Denisovans, both extinct human cousins, may have thought very similar to modern humans.”
These results do not mean that each individual is often Neanderthal or Denisovan or another combination of ancient hominids. According to researchers, on average, people in sub-Saharan Africa inherited 0.096 to 0.46 percent of their DNA from interbreeding with their human ancestors and Neanderthals. Non-Africans inherited more DNA than Neanderthals: about 0.73 to 1.3 percent. Some people also inherited part of their DNA from the Denisovans.
Researchers at the University of California, Santa Cruz, used a new computational method to examine individual DNA points in the genomes of 279 people. The team gathered the results of individual genomes into a collective image of the human genome. Each point determines that the DNA was taken from the Denisovans or Neanderthals or inherited from the common ancestors of humans and lost relatives.
Although each person may carry only one percent of Neanderthal DNA, says Kelly Harris, a population geneticist at the University of Washington in Seattle who did not participate in the study: “If you look at a few hundred people, it’s almost None of them have the Neanderthal portion of DNA in the same place as the other. “So if you add up all the areas where people have a bit of Neanderthal DNA, it will soon cover most of the genome.”
In this study, the scientists found that about 50 percent of the collective genome consists of regions where one or more individuals inherited DNA from Neanderthals or Denisovans. Most of the genome remains passed on from late human common ancestors and extinct cousins. The team of researchers isolated the inherited part from the ancient DNA. Then they looked for spots in DNA that only changed in humans and not in other species. Finally, it estimates that human-specific DNA is only a small amount between 1.5 and 7 percent of the genome.
Nathan Schaefer, a computational biologist at the University of California, Berkeley, who co-authored the paper, says the findings underscore the extent to which interbreeding between hominid species has affected the human genome. The researchers also confirmed the previous findings of other groups; The findings showed that humans interacted with Neanderthals and Denisovans, and other unknown and extinct hominids. It is unknown at this time what he will do after leaving the post. In this case, they may be closer to humans than Neanderthals. Schaefer and colleagues found that fusion between different groups of humans and hominids may have occurred many times.
The research team also found that the changes that differentiate human-only DNA occurred in several evolutionary explosions; Probably about 600,000 years ago and again about 200,000 years ago. About 600,000 years ago, humans and Neanderthals were forming branches of the hominid tree.
“In estimating the amount of purely human DNA, the amount of DNA obtained through amplification or other reasons, Deleted, not counted. Such extra or missing DNA may have allowed humans to develop new traits, “Among some of the factors involved in brain development.”
Ancient DNA is typically broken down into fragments, and researchers have collected only parts of the genome of extinct hominids. Fragmented genomes make it difficult to identify where large pieces of DNA have been lost or found. For this reason, the researchers studied only small changes in DNA that involve one or more DNA bases (parts that carry information in a molecule). Cycle states that it is not surprising that only 7% or less of the genome has evolved exclusively in human evolution, as humans and Neanderthals have relatively recently developed their own separate evolutionary pathways.
“I was not shocked by this number,” he says. In another study, if only the DNA that humans alone added to their genomes were considered, it might lead to a higher estimate of the amount of exclusively human DNA., “Or the investigation could have taken a different path.”
“By deciphering more genomes from extinct Neanderthals, Denisovans, and other hominids, researchers may find that these extinct relatives inherited some parts of DNA that seem exclusively human today,” says Harris. “The estimated amount of unique human DNA could be reduced.”