Scientists think a helpful gene variant in African populations started spreading about 85,000 years ago—before humans began their big move across Africa—because it gave people a survival edge.

What we've found so far suggests the FADS haplotype began spreading in African populations around 85,000 years ago [1]. Our analysis of the available evidence indicates this genetic variant may have provided a survival advantage during a critical period before major human migrations across Africa. The evidence we've reviewed leans toward the idea that positive selection for this haplotype started approximately 85,000 years ago [1]. This timing places the spread of the variant well before the large-scale movements of human populations within and out of Africa. While we don’t have direct experimental data, the assertion is supported by 49.0 lines of analysis pointing to this timeframe [1]. No studies in our review have refuted this claim. We interpret this to mean that the FADS haplotype likely offered a benefit in the context of ancient African environments—possibly related to diet or metabolic efficiency—allowing it to become more common over generations. However, we don’t yet know the exact nature of the advantage or the specific environmental pressures involved. Our current analysis is based on a single assertion backed by indirect evidence, so we remain cautious about drawing stronger conclusions. Since no refuting studies were identified, the evidence we’ve reviewed consistently points to this 85,000-year timeframe. Still, we recognize that new data could shift or refine this understanding over time. Practical takeaway: Based on what we’ve seen so far, this helpful gene variant likely started becoming more common in African populations tens of thousands of years ago—long before modern diets or farming—possibly because it helped people adapt to their food sources back then.