Neanderthals and modern humans continue to interbreed at the genetic level, as research led by the University of Washington School of Medicine (USA) confirms that Neanderthal DNA still influences the activation or deactivation of genes in modern humans.
Until now we were unaware of the genetic footprint that Neanderthals had left on modern humans. The new study has shown that much of its genome still exists. So much so that the impact of the Neanderthal gene probably contributes to traits as unique as height and the possibility of developing lupus or schizophrenia.
“Even 50,000 years after the last crossing between humans and Neanderthals, we can see measurable impacts on gene expression. Those changes contribute to human phenotypic variation and susceptibility to disease, ” says Joshua Akey, geneticist, co-author of the study.
Because we can only extract DNA from Neanderthal fossils and not RNA (ribonucleic acid), we had not been able to figure out how Neanderthal genes influence us. In this case, RNA sequences have been analyzed in databases of the Genotyope-Tissue Expression project of modern humans possessing Neanderthal ancestors . Then, they compared the expression of the alleles – alternative forms that the same gene can have – in 52 different tissues.
“We found that in 25% of all the tissues we analyzed, we were able to identify differences in expression between the Neanderthal allele and the modern human allele ,” says study co-author Rajiv McCoy.
Akey notes that “we can deduce that the greatest differences in gene regulation between modern humans and Neanderthals are found in the brain and testes.”
Thus, one of the Neanderthal genes discovered reduces the risk of schizophrenia but influences height. This is the ADMTSL3 gene.
“Our results demonstrate that the causal mutation was inherited from Neanderthals,” concludes McCoy.
The study has been published in the journal Cell.
