The sequencing of the human genome has highlighted the genetic differences and divergence timelines between modern humans and chimpanzees. The Human Genome Project revealed the extensive genetic diversity within modern humans, and the discovery of early modern human and extinct archaic human genomes has offered new insights into past human migrations and evolution... In recent years, genetic research has provided us with a fresh perspective on the origins and uniqueness of modern humans from a biological standpoint.
On the occasion of its 50th anniversary, the journal Cell published a special issue discussing the cutting-edge scientific question of "human origins and evolution" from a genetic standpoint. For her groundbreaking contributions to the field of human evolution research, Fu Qiaomei, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, was invited to write a review article specifically on the evolutionary path of modern humans. This article was published online in Cell on March 1st.
"We systematically interpreted the development process of genetic traits in modern humans from an ancient genomics perspective, explored the migration and integration patterns, population sizes, and the history of adaptive variations of past humans, and offered profound insights into the uniqueness and advantageous traits of modern humans compared to other extinct human groups and species," Fu Qiaomei stated.
By directly comparing the genome sequences of modern humans with those of extinct archaic humans, researchers can more closely track the origins of modern humans and the changes in significant phenotypes, thereby distinguishing their genetic traits from Neanderthals, Denisovans, and others, and discussing the advantages and fundamental reasons why modern humans have survived to this day compared to extinct archaic humans.
In theory, this direct approach to ancient genomics is an extremely powerful tool that can reveal the genetic changes behind the modern human genome. However, due to the limited ancient genome data available from extinct archaic humans and early modern humans, the genetic diversity of these ancient groups has not been fully understood, which greatly limits the application of this method.
Despite this, researchers have still made significant discoveries using the direct method. For instance, the unique gene sequences found in current modern humans that were absent in extinct archaic humans only account for 7% of the entire modern human genome.
Moreover, by decoding the ancient genome information of extinct archaic humans and early modern humans, researchers can clarify the genetic differences between these human groups, gaining a better understanding of their behaviors and survival details, such as population sizes, family structures, migration paths, etc., providing new perspectives on the advantageous traits that allowed modern humans to continue expanding and developing at the population level.
"This represents another important method of ancient genomics research—the indirect method, which can reconstruct the survival history of extinct archaic humans and early modern humans," Fu Qiaomei explained.
Based on existing research results, the article pointed out that there were indeed some differences between early modern human populations and extinct archaic human groups. For example, the effective population size of early modern human groups has always been much larger than that of extinct archaic human groups like the Neanderthals, which helped modern humans maintain a high level of genetic diversity over a longer period and in a broader geographical range, better adapting to environmental changes.
Fu Qiaomei's team summarized two methods of tracing the evolutionary path of modern humans—the direct and indirect methods. Although limited by the scarcity of existing ancient genome data, these methods still demonstrate the significant contribution and potential of ancient genomics in addressing the question of "human origins and evolution."
The article discussed the similarities and relative advantages of modern humans over extinct archaic humans and other species in the evolutionary process from both direct and indirect perspectives, at both individual and population levels. This also provides a clearer research direction for further refining the evolutionary path and deep phylogenetic structure of modern humans.
Events in prehistoric history have contributed to the overall fitness of human populations, facilitating further survival and dispersal of modern humans globally.
(Image courtesy of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences.)
