Y chromosome, the missing link between us, Neanderthal

Washington DC: To this day, individuals of European and Asian heritage retain Neanderthal DNA in their genomes and now, a new study suggests that we did not inherit male genes from them.

The Stanford University researchers completed the first in-depth genetic analysis of a Neanderthal Y chromosome. The findings offer new insights into the relationship between Neanderthals and modern humans and some of the genetic factors that might have kept the two lineages apart.

The Y chromosome was the main component remaining to be analyzed from the Neanderthal genome, the researchers said.

Researcher Fernando Mendez explained that characterizing the Neanderthal Y chromosome helped them to better understand the population divergence that led to Neanderthals and modern humans. It also enabled them to explore possible genetic interactions between archaic and modern gene variants within hybrid offspring.

Mendez and his colleagues, including Carlos Bustamante from the Max Planck Institute for Evolutionary Anthropology in Germany, analyzed the Y chromosome from a Neanderthal male found in El Sidron, Spain. Their analysis suggests that Neanderthals and modern humans diverged almost 590,000 years ago, consistent with earlier evidence.

The researchers say that the Neanderthal Y chromosome they sequenced is distinct from any Y chromosome observed in modern humans, suggesting that the lineage in question is to be extinct. They also found some intriguing protein-coding differences between genes on the Neanderthal and modern human Y chromosomes.

Mendez noted that the finding that most of the functional differences associate with these genes, rather than with genes involved in sperm production, came as a surprise.

The researchers say additional research is required to confirm the role of those Y-chromosome mutations in discouraging the formation of a hybrid Neanderthal and human species. They are planning those experiments now.

The study appears in the American Journal of Human Genetics.