Human evolution: Neanderthal footprints in African genomes.

Area of Science:

• Paleogenetics
• Human Evolution
• Population Genomics

Background:

• Interactions between Homo sapiens and Neanderthals occurred over tens of thousands of years.
• Genetic exchange (introgression) between these hominin groups is evidenced in non-African modern human genomes.
• The extent and impact of Neanderthal introgression in African populations remain less understood.

Purpose of the Study:

• To investigate the history and patterns of Neanderthal introgression in diverse African populations.
• To identify specific genomic regions affected by gene flow from Neanderthals.
• To analyze the role of natural selection on introgressed Neanderthal DNA within African ancestries.

Main Methods:

• Whole-genome sequencing of individuals from various African populations.
• Advanced bioinformatic analyses to detect archaic hominin DNA segments.
• Statistical modeling to infer the directionality and timing of gene flow.
• Selection scans to identify regions under positive or negative selection.

Main Results:

• Evidence of bidirectional gene flow between Neanderthals and early modern humans, with some Neanderthal DNA introgressing into African populations.
• Identification of specific Neanderthal-derived alleles present in African genomes, contrary to previous assumptions.
• Genomic regions with introgressed Neanderthal DNA show signals of adaptive selection, suggesting functional impact.

Conclusions:

• Neanderthal gene flow into Africa was more complex than previously thought, involving multiple introgression events.
• Natural selection actively shaped the fate of introgressed Neanderthal DNA in African populations.
• These findings necessitate a re-evaluation of human evolutionary history and the genetic legacy of archaic hominins.