Neanderthal Gene Linked to Extra Muscle Mass; Two Ancient Lineages Found in Human DNA

A Neanderthal gene carried by millions of people today has been found to build extra muscle mass, revealing what ancient DNA actually does.

Millions of living humans carry a gene inherited from Neanderthals that demonstrably increases muscle mass — and scientists have now worked out the biological mechanism behind it. The gene, carried over from interbreeding between early modern humans and Neanderthals tens of thousands of years ago, influences muscle fiber development in its carriers today. This is among the clearest functional explanations yet found for why Neanderthal DNA persists in the human genome at all — it apparently conferred a physical advantage that natural selection preserved. Beyond Neanderthals, researchers also identified genetic contributions from a second ancient lineage, sometimes called a 'ghost species' because it is known only through DNA traces rather than a well-characterized fossil record. These archaic sequences are woven into the genomes of modern humans alongside the better-documented Neanderthal inheritance. The findings add to a growing body of research showing that interbreeding between Homo sapiens and other archaic human relatives was not a marginal event but one with lasting biological consequences. Non-African populations typically carry around 1–2% Neanderthal DNA, a figure that has been established for over a decade, but pinning down what specific inherited sequences actually do in living bodies has remained a harder scientific challenge.

Why it matters

Understanding which archaic genes are still active — and what they do — helps explain human variation in traits like muscle composition and disease susceptibility. It also reshapes how scientists define the boundaries between ancient human species.

What's next

Researchers are expected to continue mapping the functional effects of other archaic gene variants to determine which additional traits may have roots in Neanderthal or other ancient lineages.

Key facts

• A specific Neanderthal-derived gene has been linked to increased muscle mass in modern human carriers
• Scientists identified the biological mechanism by which this gene affects muscle fiber development
• DNA from a second unidentified archaic lineage, dubbed a 'ghost species,' was also found in modern human genomes
• Non-African modern humans typically carry roughly 1–2% Neanderthal DNA from ancient interbreeding
• The ghost species is known only from genetic traces, with no well-characterized fossil record to match

Bias & framing notes

Both sources cover the same research but with different emphasis: Newsweek focused tightly on the Neanderthal muscle-mass finding and its practical relevance to living people, while Yahoo led with the more dramatic 'two ghost species' framing, emphasizing mystery and breadth. Neither source provided enough methodological detail — such as the study name, journal, or lead researchers — to fully verify the findings independently. The limited sourcing and lack of primary citation details prevent a higher trust score.

NewsClear — neutral news & congressional tracking · Bill of the Week