However, a group of researchers claimed that they had narrowed down the exact scope. According to a new study published in the scientific journal Nature, modern humans originated in northern Botswana about 200,000 years ago. The research team narrowed the place where humans evolved to the makgadikkadi-oka vango ancient wetland south of Zambezi River.
The researchers collected the DNA of Khoe-San people in southern Africa, who represented the earliest maternal lineage of human beings and those who did not consider themselves as Khoe-San people, but the researchers predicted that they also carried these lineages.
They analyzed DNA fibers in more than 1, 200 mitochondrial genomes. We only inherited our mother's mitochondrial DNA, so there is little change between generations. The researchers focused on L0 mitochondrial DNA, the genome found on the first branch of the earliest pedigree of all modern human maternal ancestors.
They cooperated with geologists and climate physicists to understand the climate, land and geology of this period, and found that there were a large number of L0 people on the Zambezi River 200,000 years ago, and several Kuisan subsystems were the dominant population in the world at that time.
This area used to be Lake Makgadikgadi, which crossed from northern Namibia to northern Botswana and entered Zimbabwe. Researchers say that it was originally the largest lake in Africa today, and it survived for about 200 million years before it was decomposed by moving tectonic plates and formed wetlands in situ.
Researchers believe that the disintegration of the lake increased humidity, opened up lush animal and plant life, and made people migrate to the northeast and southwest after living for 700 thousand years.
However, some experts warn that any statement about the origin of human beings must investigate the whole genome, because mitochondria only account for a small part of our genome and only represent our direct maternal line, said Carina Schlebusch, an associate professor of human evolution at Uppsala University in Sweden.
"This doesn't represent all the other potential ancestors we may have," she said. "Therefore, genetic variation can only be captured by the rest of our chromosomes. The ancestors of mitochondrial descent were not the only people who lived in Africa 200,000 years ago. Eleanor Serry, a professor and independent leader of the Pan-African Evolution Research Group at the Max Planck Institute for Human History Science, said that they may not have spread the rest of the DNA.
"Rebuilding a deep ancestor from mitochondrial DNA is like trying to rebuild a language from a few words, while using whole genome or nuclear DNA is like trying to rebuild a dead language after hearing it for a day," she said. Researchers choose to study the mitochondrial genome because it is the most accurate way to determine the timeline and see where the pedigree appears in the absence of genome-wide data.
Eva Chan, one of the authors of this study and a senior research officer in human comparative cancer and prostate cancer genomics at the Gavin Institute, said that the origin of our ancestors is a hotly debated topic. With more data, the theory will change, but all our evidence points to this ancient wetland as the birthplace of all human beings today.
"We can include the sequence of the whole genome, but the power of the computer is still limited. At present, only the whole genomes of several individuals can be compared. This paper contradicts some recent findings, which show that human beings originated in other parts of Africa. For example, the analysis of male inheritance of Y chromosome shows that the earliest modern humans may have appeared in West Africa, not South Africa.
However, a reliable argument about the origin of human beings needs to explain more than genetics, Scerri said. "This paper ignores a large area of fossils and archaeological evidence, which supports the older origin of our species," she said. James Cole, chief lecturer in archaeology at Brighton University, said that the archaeological evidence of different fossils in Africa questioned the basic findings of this study. "You may think that the story of human evolution began 200,000 years ago, but we know from fossils and archaeological records that the evolution of Homo sapiens began about 300,000 years ago.
This includes some skull and jaw remains, stone tools and fire evidence found in Morocco, North Africa. Previously, only evidence was found in the south and east. Cole said that although this new study helps us to know more about where we come from, it also highlights how complicated our evolution is.
"Population connections are emerging everywhere-this study shows that about 200,000 years ago, a very powerful population survived genetically in today's population, but there will be others.
"From archaeological and fossil records, we know that human evolution is complicated, but we don't know how complicated it is until paleontologists start lighting torches in complex dark blocks and emphasize the chain we can pull out to understand where we come from," Cole said.
This paper rekindled the argument that modern human beings did not originate from any place, but many groups shaped what we are today, and the whole African continent may be the origin of our species.
In a popular paper published last year, Scerri believes that various genetic characteristics have evolved in different parts of Africa. Jon Marks, a professor of anthropology at the University of North Carolina, said that this was his "first choice" when teaching the origin of human beings in Africa, rather than "trying to determine where the first man with a chin and forehead lived".
However, in addition to more and more evidence supporting the origin theory of the whole continent, there is another reason why scientists reject the theory that modern humans came from one place. This new paper is based on the assumption that the Khoisan people have lived in one place for hundreds of thousands of years. Max pointed out that it mentioned anatomically modern humans, but did not study bones. The connection between mitochondrial DNA 200,000 years ago and anatomically correct humans at the same time is unknown. In fact, he added, there may be no relationship between the two.
He said that the author put forward a good reason that the earliest mitochondrial DNA was in southern Africa 200 thousand years ago, but how do we know that the people sampled in the study have not moved in the past 200 thousand years?
"It takes a lot of time to live in the same place," Max said. Some researchers believe that any argument that the contemporary population represents the earliest modern people is problematic, especially the population that may have existed in the past.
"Accepting these results means accepting that Khoe-San is a relic of evolution, which has neither changed nor moved geographically for tens of thousands or even hundreds of thousands of years," Scerri said. 20 19 do we really need to point out how incorrect and morally problematic this view is in fact? "
-Text extracted from Internet translation.