What Have Neanderthals Done for Us? The Claims That Survive a Fact Check

The story that sent me looking

Like many of you, I have a weakness for Neanderthal stories. They make evolution feel wonderfully close: a vanished cousin, a few fragments of DNA still carried in our genomes, and suddenly a possible explanation for our muscles, our pregnancies, our immune systems, or even the shape of our noses.

But that fascination also makes us easy targets for hype. And I am increasingly tired of journalists exploiting it, turning intriguing but often modest genetic associations into sweeping stories about what Neanderthals supposedly “gave” us.

That was my reaction to an MDR WISSEN / RR article from 9 August 2026, Muskeln, Kiefer, Schmerzen: Was der Neandertaler in unserem Körper hinterlassen hat (“Muscles, jaw, pain: what Neanderthals left in our bodies”). It begins with a new finding about a Neanderthal-derived growth-hormone receptor, then opens out into a much larger, irresistible catalogue of things Neanderthals may have left us.

Here is the story the article invites us to picture:

• A Neanderthal growth-hormone-receptor variant is linked to more muscle mass and is found in about 20% of South Asians, but only about 0.5% of Europeans (this was covered in my previous post)

• Nearly one in three women in Europe carry a Neanderthal progesterone-receptor version and have fewer early-pregnancy bleeds and miscarriages.

• Three major risk factors for Dupuytren’s contracture—the hand condition nicknamed “Viking disease”—come from Neanderthals.

• A chromosome-3 Neanderthal segment is a major early-COVID severity risk locus, appears in roughly one in six Europeans, and lowers HIV-infection risk by 27%.

• Other Neanderthal fragments improve defence against bacteria and fungi but raise allergy risk; make blood clot faster but raise stroke and pulmonary-embolism risk; and affect nasal height, fat metabolism and the roundness of the internal braincase.

That is a very good list of questions. It is also a very compressed way of telling several different kinds of genetic story. MDR directly links the new growth-hormone-receptor research; the rest appears as background in the article, without individual study citations. So I used the MDR piece as the doorway, then went back to the studies behind the claims.

I have already written about the first, GHR/muscle claim in Did the ‘Neanderthal Muscle Gene’ Really Turn Modern Humans into Muscle Heads? I will not repeat that analysis here. The short version is that the molecular and body-composition association is real, but it does not turn a carrier into a “muscle head,” explain athletic strength, or explain Neanderthal physique, or even differences between modern populations. The nine remaining claims are what I want to walk through here.

Before doing so, one piece of scale helps me keep my footing. In a large study of 96 traits in 291,273 unrelated White British UK Biobank participants, introgressed variants collectively explained an average of 0.12% of trait variation. That is not nothing. But it is a useful antidote to the idea that a surviving Neanderthal fragment is a miniature destiny (Wei et al. (2023)

The question I keep asking

When I read “a Neanderthal gene,” I pause. Usually the phrase means a stretch of introgressed DNA—or a modern marker that travels with it—not a single gene with one simple effect. The causal variant may still be uncertain. The population in which a finding was made may be very different from the population in which it is being repeated. And “white,” “South Asian,” and “Northern European” are not interchangeable genetic categories.

For each claim, I came back to three questions:

• Is this really an introgressed Neanderthal segment?

• What, exactly, did the study measure, and in whom?

• Does the evidence earn the big words: prevents, protects, makes, causes or adaptive?

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