Plate Nº 76 · recorded November 14, 2026
Biology & EvolutionReported finding
10,000 Years of Sheep Breeding Left a Mark in Gene Regulation
Scientists mapped 6,761 samples across 51 sheep tissues and found 10,000 years of breeding reshaped not just genes, but how they're regulated — with hints of wool selection.
By Nathan Brooks4 min read753 words
In brief
- SheepGTEx maps hundreds of thousands of gene regulatory effects across 51 sheep tissues, using 6,761 samples from 2,816 animals.
- DNA from 52 ancient sheep spanning ~10,000 years revealed selection's effects on gene regulation, published in Nature Genetics (2026).
- Tissue-specific regulatory variants showed stronger selection signatures than multi-tissue variants.
- A THNSL2 skin-activity variant grew more common in European sheep between the Neolithic and the Middle Ages.
- FXYD1 regulation in the pituitary gland offers a testable — but unproven — hypothesis about litter size.
By Nathan Brooks
Sheep carry the fingerprints of 10,000 years of human breeding — and not just in their DNA sequences, but in how their genes are switched on and off. That's the headline finding of an international study published in Nature Genetics in 2026, built on the most comprehensive map of gene regulation in sheep to date.
The atlas, called SheepGTEx, draws on 6,761 RNA-sequencing samples from 2,816 sheep. It spans 51 different tissues and cell types, and it maps hundreds of thousands of genetic regulatory effects — in plain English, spots in the genome where a letter change influences how active a particular gene is, and where in the body that happens.
Researchers from Aarhus University joined colleagues worldwide to build it. The project also relied on DNA from 52 ancient sheep spanning roughly 10,000 years, letting the team watch breeding's effects play out across millennia.
What did 10,000 years of selection do?
The most striking result: variants that regulate genes in just one or a few tissues showed stronger signatures of natural and human selection than variants that act across many tissues.
"What surprised me most was the relationship between tissue-specific gene regulation and the genetic signatures left by selection. Our findings suggest that domestication and breeding may have altered particular traits by changing gene regulation in specific tissues," said Lingzhao Fang, associate professor at Aarhus University's Center for Quantitative Genetics and Genomics.
That matters because genes don't behave identically everywhere. A variant can crank a gene up in skin while leaving it untouched in the liver — and if breeders were selecting for wool, skin-specific changes are exactly what you'd expect to accumulate.
The team found exactly that kind of pattern. Thousands of years of selective breeding left marks on regulatory variants active in the skin and the cervix, consistent with human preferences for wool, pigmentation and reproduction.
How do you watch a gene's popularity rise over 8,000 years?
One gene, THNSL2, offers the clearest example. A variant linked to higher THNSL2 activity in skin became generally more common among European sheep between the Neolithic period and the Middle Ages, though its frequency fluctuated along the way.
The detail is intriguing because wool grows from hair follicles in the skin. The researchers are careful here: they have not shown a direct effect on wool production. But the timeline hints that domestication reshaped not just which genes sheep carry, but how loudly those genes are expressed where it counts.
"What makes this finding particularly interesting is that we can trace how a genetic variant associated with gene activity in the skin became more common over thousands of years. It gives us a glimpse of how domestication may have shaped not only the genes sheep carry but also how those genes are regulated," Fang said.
Why build a 51-tissue atlas anyway?
Until now, genetic studies could link genome regions to traits but often couldn't name the genes involved, the mechanisms at work, or the tissues where the variants act. SheepGTEx closes part of that gap by connecting variants to specific genes and the tissues where they operate.
It's already generating leads on modern livestock. The team identified a regulatory association with a gene called FXYD1 in the anterior pituitary gland — a hormone-producing tissue central to reproduction. The finding offers a testable hypothesis about differences in litter size.
A necessary hedge: the study does not prove FXYD1 determines how many lambs a ewe produces. It gives researchers a specific biological lead to test experimentally.
What's next for breeding programs?
Modern breeding already uses genetic markers to predict an animal's potential, but scientists don't always know the biology behind those markers. SheepGTEx can flag variants likely to have real functional effects on traits like fertility and wool quality.
Plenty of validation remains. Candidate variants need testing in independent sheep populations, their biological effects need confirming, and researchers must show the data actually improves genomic prediction accuracy.
"We now have a much stronger foundation for identifying the genetic variants that deserve further investigation. In the longer term, our goal is to translate this knowledge into more precise breeding tools," Fang said.
The atlas is publicly available, so researchers anywhere can start asking new questions about sheep biology and evolution.
The paper: Mian Gong et al., "A multi-tissue atlas of genetic regulatory effects in sheep," Nature Genetics (2026). DOI: 10.1038/s41588-026-02825-2.
via phys.org/rss-feed/ (Source)
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