Final answer:
Modern non-African human genomes include about 1-4 percent Neandertal DNA, reflecting interbreeding events as human populations moved out of Africa and encountered Neandertals in Europe and Asia.
Step-by-step explanation:
Modern non-African human genomes contain a notable contribution from Neandertals. Sophisticated genetic analyses and fossil studies report that modern human populations outside of Africa have approximately 1-4 percent of their genome derived from Neandertals. This genetic contribution is indicative of interbreeding between Homo sapiens and Neandertals as early humans migrated out of Africa and encountered Neandertals in Europe and Asia.
Further genetic evidence from a bone found in Siberia suggests that a girl had a Neandertal mother and a Denisovan father, highlighting the complex interactions between ancient hominin species. These findings reflect how Neandertal genes have been dispersed among modern Eurasian populations, influencing genetic diversity and potential susceptibilities to certain conditions.
Several research studies suggest that the influence of Neandertal genes included benefits such as immunities against some viruses, while potentially increasing risks for certain health issues. Hence, modern human genetic ancestry is a mosaic shaped by the intermingling of Homo sapiens with Neandertals and other hominin species.