Slideshow code developed in collaboration with ChatGPT3 at https://chat.openai.com/
Homo sapiens skull (left) and Neanderthal skull (right)
As modern humans migrated out of Africa, they came into contact with the descendants of an earlier hominin migration - Neanderthals and their cousins the Denisovans. This period of interbreeding probably lasted about 10,000 years until the last Neanderthals disappeared about 40,000 years ago.
Some have recently proposed that interbreeding may have resulted in the relatively small population of Neanderthals being absorbed into the larger and growing population of Homo sapiens. Proponents of this idea have pointed out that there is more Neanderthal DNA around nowadays, in the form of 1-4% of the genome of people of non-African origins, than ever existed when Neanderthals were alive.
According to recent research by a team of scientists from several institutions, including Cornell, some of those genes are still active and influencing human traits including several with a significant influence on the immune system.
The study and its findings are the subject of a press release by Cornell, and an open access paper in eLife:
Recent scientific discoveries have shown that Neanderthal genes comprise some 1 to 4% of the genome of present-day humans whose ancestors migrated out of Africa, but the question remained open on how much those genes are still actively influencing human traits — until now.The publication in eLife includes the editor's evaluation and links to the peer-reviewers' comments and the team's responses to them. These should make interesting reading to creationists who have been fooled into believing that peer-review is to ensure the publication conforms to scientific dogma, just like the 'peer-review' claimed by creation 'scientists'.
A multi-institution research team including Cornell has developed a new suite of computational genetic tools to address the genetic effects of interbreeding between humans of non-African ancestry and Neanderthals that took place some 50,000 years ago. (The study applies only to descendants of those who migrated from Africa before Neanderthals died out, and in particular, those of European ancestry.)
In a study published in eLife, the researchers reported that some Neanderthal genes are responsible for certain traits in modern humans, including several with a significant influence on the immune system. Overall, however, the study shows that modern human genes are winning out over successive generations.Interestingly, we found that several of the identified genes involved in modern human immune, metabolic and developmental systems might have influenced human evolution after the ancestors’ migration out of Africa. We have made our custom software available for free download and use by anyone interested in further research.
Assistant professor April (Xinzhu) Wei, lead-author
Assistant professor of computational biology
College of Arts and Sciences
Cornell University, NY, USA.
Using a vast dataset from the UK Biobank consisting of genetic and trait information of nearly 300,000 Brits of non-African ancestry, the researchers analyzed more than 235,000 genetic variants likely to have originated from Neanderthals. They found that 4,303 of those differences in DNA are playing a substantial role in modern humans and influencing 47 distinct genetic traits, such as how fast someone can burn calories or a person’s natural immune resistance to certain diseases.
Unlike previous studies that could not fully exclude genes from modern human variants, the new study leveraged more precise statistical methods to focus on the variants attributable to Neanderthal genes.For scientists studying human evolution interested in understanding how interbreeding with archaic humans tens of thousands of years ago still shapes the biology of many present-day humans, this study can fill in some of those blanks. More broadly, our findings can also provide new insights for evolutionary biologists looking at how the echoes of these types of events may have both beneficial and detrimental consequences.
Associate professor, Sriram Sankararaman, Corresponding author
Department of Human Genetics
University of California, Los Angeles, CA, USA.
While the study used a dataset of almost exclusively white individuals living in the United Kingdom, the new computational methods developed by the team could offer a path forward in gleaning evolutionary insights from other large databases to delve deeper into archaic humans’ genetic influences on modern humans.
The other co-lead author on the study is Christopher Robles, postdoctoral researcher at UCLA. Additional authors are UCLA doctoral student Ali Pazokitoroudi; Andrea Ganna of Massachusetts General Hospital and the Broad Institute of MIT and Harvard; Alexander Gusev and Arun Durvasula of Harvard Medical School; Steven Gazal of USC; Po-Ru Loh of the Broad Institute of MIT and Harvard; and David Reich of Harvard University.
Also included is a link to the decision letter which suggests further clarification and inclusions, and the team’s response. With the peer-reviewers’ comments, the editor's comments and the decision letter, these give some insight into the process of publishing a research paper. Creationists might like to ignore them, or risk having their delusions spoilt.
AbstractIt almost goes without saying that this research refutes several basic creationist superstitions, namely:
The genetic variants introduced into the ancestors of modern humans from interbreeding with Neanderthals have been suggested to contribute an unexpected extent to complex human traits. However, testing this hypothesis has been challenging due to the idiosyncratic population genetic properties of introgressed variants. We developed rigorous methods to assess the contribution of introgressed Neanderthal variants to heritable trait variation and applied these methods to analyze 235,592 introgressed Neanderthal variants and 96 distinct phenotypes measured in about 300,000 unrelated white British individuals in the UK Biobank. Introgressed Neanderthal variants make a significant contribution to trait variation (explaining 0.12% of trait variation on average). However, the contribution of introgressed variants tends to be significantly depleted relative to modern human variants matched for allele frequency and linkage disequilibrium (about 59% depletion on average), consistent with purifying selection on introgressed variants. Different from previous studies (McArthur et al., 2021), we find no evidence for elevated heritability across the phenotypes examined. We identified 348 independent significant associations of introgressed Neanderthal variants with 64 phenotypes. Previous work (Skov et al., 2020) has suggested that a majority of such associations are likely driven by statistical association with nearby modern human variants that are the true causal variants. Applying a customized fine-mapping led us to identify 112 regions across 47 phenotypes containing 4303 unique genetic variants where introgressed variants are highly likely to have a phenotypic effect. Examination of these variants reveals their substantial impact on genes that are important for the immune system, development, and metabolism.
Xinzhu WeiChristopher R RoblesAli PazokitoroudiAndrea GannaAlexander GusevArun DurvasulaSteven GazalPo-Ru LohDavid ReichSriram Sankararaman (2023)
The lingering effects of Neanderthal introgression on human complex traits
eLife 12:e80757. DOI: 10.7554/eLife.80757
Copyright: © [year] The authors.
Published by [publisher]. Open access
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
Editor's evaluation
Humans whose genetic ancestors lived outside Africa have a small proportion of the genome that traces back to interbreeding events with Neanderthals. To quantify the contribution of this ancestry to present-day phenotypic variation, the authors develop a convincing set of approaches that takes into account various complicating factors and apply it to a subset of the UK Biobank individuals. The work is an important contribution to human evolution and evolutionary biology more generally.
- Special creation without ancestors of a founder couple who then committed the original sin for which we all now need forgiveness and redemption even though a blood sacrifice supposedly gave us vicarious redemption 2000 years ago. Not only was there never a single founder couple, there was not even a single founder species!
- Scientists are increasingly rejecting the Theory of Evolution (TOE) as the best available explanation of the facts, in favour of creationism's childish magical superstition with an unproven supernatural entity. In fact, these scientists explain the survival of the ingressed Neanderthal genes in contemporary, non-African H. sapiens in terms of the evolutionary advantage they carried, in the Eurasian environment. No doubt there that the TOE provides the best explanation of the observable facts.
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