Got a Brawny Build? Thank Your Neanderthal Ancestors

Ever looked in the mirror and thought, "Where did all this… robustness come from?" You might have your ancient Neanderthal relatives to thank. Apparently, a specific gene variant passed down from those burly predecessors could be making some modern humans a little taller and a lot more muscular. Because, naturally, our genes still can't let go of the caveman physique.

Neanderthals, for those who skipped ancient history, roamed Europe and Asia between 400,000 and 40,000 years ago. Before they vanished, they did a bit of intermingling with early Homo sapiens. The result? A genetic legacy that means most non-African people today carry a modest 1 to 4 percent Neanderthal DNA. Just enough to keep things interesting.

The Ancestral Pump-Up

New research, published in Current Biology, suggests this ancient DNA isn't just taking up space. It's actively influencing us. Scientists found that a particular Neanderthal gene variant seems to be cranking up the growth hormone pathway in some folks. This pathway, for the uninitiated, is basically your brain's pituitary gland telling your bones and muscles to get busy growing. And apparently, Neanderthals had a slightly different instruction manual.

Researchers suspected this might be the case, given Neanderthals' famously "robust" physique — think thicker bones, broader chests, and muscles that probably made modern gym-goers look like twigs. By comparing modern human and Neanderthal genetic blueprints, they zeroed in on two DNA variants in the growth hormone receptor gene that frequently appear together in people today.

And here’s a fun twist: this particular gene form, or allele, isn't evenly distributed. It's most common in people of South and East Asian ancestry, showing up in up to 24% of those populations. Europeans? A mere 0.5%. Indigenous Americans? About 2%. So much for the stereotype of the distinctly European-looking Neanderthal. Turns out, their genetic influence is a bit more global.

Bigger Cells, Leaner Mass

The scientists then checked if carrying this Neanderthal variant actually made a difference. They sifted through data from over 1.1 million adults (because apparently, that's where we are now). The verdict? People with the Neanderthal variant were, on average, 0.12 inches taller and 0.6 pounds heavier. Not exactly a Hulk transformation, but every little bit counts.

"When we looked more closely at where that weight increase comes from, we saw that it’s an increase in lean muscle mass," noted study co-author Philipp Kanis. So, not just bigger, but brawnier. Modern humans with this variant also displayed subtle Neanderthal-esque traits, like shorter tooth roots and a slightly different jawbone structure. Because why stop at muscle when you can get a bonus jawline, right?

To really nail it down, researchers grew cells with either the Neanderthal or modern human gene variant and exposed them to growth hormones. The Neanderthal variant cells responded with gusto, multiplying into nearly 40% more cells over five days. Let that satisfying number sink in.

This all suggests that while this variant won't turn you into a full-blown Neanderthal (thankfully, no one needs that much body hair), it might just be responsible for that extra bit of muscle or height you're carrying around. It’s a subtle nod to our ancient past, reminding us that even tens of thousands of years later, our ancestors are still, quite literally, building us up. Just don't blame them for your stubborn belly fat; they probably didn't have fast food.