Mounting evidence suggests Neanderthals also had a habit of inbreeding, or conceiving with close relatives. Several studies have now reported this based on genetic patterns and bone abnormalities thought to result from intra-family flings.
First, let’s review the facts behind these claims of consanguinity, or mating between relatives. Then let’s consider the consequences: How did inbreeding impact Neanderthal health and survival?
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The first strong case of Neanderthal inbreeding came in 2014, when scientists published a genome extracted from a toe bone found in the Altai Mountains of Siberia. Alive roughly 120,000 years ago, this Neanderthal woman had closely related parents: half-siblings, double first cousins, an uncle-niece couple or some other combo with equal relatedness.
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[Consanguinity] causes so-called inbreeding depression: inbred individuals have reduced evolutionary fitness, or survival and reproductive success.…
Until we have more genomes, it’s hard to gauge the prevalence of inbreeding and its impact on the species overall. But we can say confidently, some Neanderthals were inbred and that didn’t help their chances of surviving. Maybe it even contributed to their extinction. Hey, if inbreeding took down royal dynasties, it may have taken a toll on Neanderthals, too.
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