The evolutionary history of human spindle genes includes back-and-forth gene flow with Neandertals

Abstract

Proteins associated with the spindle apparatus, a cytoskeletal structure that ensures the proper segregation of chromosomes during cell division, experienced an unusual number of amino acid substitutions in modern humans after the split from the ancestors of Neandertals and Denisovans. Here, we analyze the history of these substitutions and show that some of the genes in which they occur may have been targets of positive selection. We also find that the two changes in the kinetochore scaffold 1 (KNL1) protein, previously believed to be specific to modern humans, were present in some Neandertals. We show that the KNL1 gene of these Neandertals shared a common ancestor with present-day Africans about 200,000 years ago due to gene flow from the ancestors (or relatives) of modern humans into Neandertals. Subsequently, some non-Africans inherited this modern human-like gene variant from Neandertals, but none inherited the ancestral gene variants. These results add to the growing evidence of early contacts between modern humans and archaic groups in Eurasia and illustrate the intricate relationships among these groups.

Production method of the Königsaue birch tar documents cumulative culture in Neanderthals

“…Recent evidence indicates possible early Homo sapiens incursions into southern Europe, overlapping (France (Slimak et al 2022)) or predating (Southern Greece (Harvati et al 2019)) the time frame of the Königsaue birch tar artefacts. These findings are supported by paleo-genetic analyses (Peyrégne et al 2022;Posth et al 2017). Thus, the possibility of cultural exchange cannot be completely excluded and should be further investigated.…”