Loss of olfactory receptor function in hominin evolution.

Area of Science:

• Genomics
• Evolutionary Biology
• Paleontology

Background:

• The mammalian sense of smell relies on olfactory receptors (ORs), the largest gene family.
• Gene gain and loss in ORs correlate with ecological niche adaptations.
• Modern humans possess 853 OR genes, with 55% non-functional.

Purpose of the Study:

• To investigate olfactory receptor gene loss in Neanderthal and Denisovan genomes.
• To compare functional OR gene repertoires across hominin lineages.
• To infer sensory niche differences using genomic data.

Main Methods:

• Comparative genomic analysis of hominin genomes.
• Identification of olfactory receptor gene loss-of-function variants.
• Correlation of genetic findings with fossil morphology.

Main Results:

• Evidence of 10 Neanderthal and 8 Denisovan ORs with distinct loss-of-function compared to modern humans.
• Observed OR loss-of-function shared with subsets of modern humans or unique to lineages.
• Cranial morphology in Neanderthals suggests altered sensory arrangements.

Conclusions:

• Significant differences in functional olfactory receptor genes exist among modern humans, Neanderthals, and Denisovans.
• Varied loss of function across these taxa indicates divergent evolutionary paths in olfaction.
• Genomic analysis is crucial for understanding the sensory ecology of extinct species.