From littoral.homo@gmail.com@21:1/5 to All on Tue Nov 1 03:59:59 2022
Adaptive Evolution of the FADS Gene Cluster within Africa
Rasika A Mathias cs 2012 PLoS ONE doi org/10.1371/journal.pone.0044926
Long-chain poly-unsaturated fatty acids LC-PUFAs are essential for brain structure, development & function:
adequate dietary quantities of LC-PUFAs are thought to have been necessary for brain expansion & the increase in brain complexity during Hs evolution.
Previous studies in largely European populations suggest: Hs have limited capacity to synthesize brain LC-PUFAs (e.g. docosahexaenoic acid DHA) from plant-based medium-chain MC-PUFAs, due to limited desaturase FADS activity.
Population-based differences in LC-PUFA levels & their product-to-substrate ratios can (in part) be explained by polymorphisms in the FADS gene-cluster, which have been ass.x increased conversion of MC- to LC-PUFAs.
Here we show evidence:
these high-efficiency converter alleles in the FADS gene-cluster were likely driven to near-fixation in African populations by positive selection ∼85 ka:
did selection at FADS variants (which increase LC-PUFA synthesis from plant-based MC-PUFAs) allow African populations, obligatorily tethered to marine sources for LC-PUFAs in isolated geographic regions, to rapidly expand throughout the African continent
60–80 ka?