Genes Linked to the Stripes of Wild Boar Piglets

September 25, 2026

Striped juvenile wild boar in the Palatinate Forest, Germany

Research: Genetics & genomics, Molecular biology & biochemistry

The pale longitudinal stripes of a wild boar (Sus scrofa) piglet are an inborn camouflage pattern that fades as the animal grows. A new genetic study combined a large breeding experiment with gene-expression and chromatin analyses to investigate both what can disrupt this juvenile pattern and why adjacent areas of skin become dark or light.

The researchers first analysed 932 second-generation offspring from crosses between two domestic pig breeds, white Duroc and Erhualian: 132 had juvenile stripes and 800 did not. They also drew on existing genome sequences from 13 Chinese wild boars. The molecular comparison then used dark and light skin from three two-day-old striped piglets whose parents were a northern Chinese wild boar and a local domestic pig. This combination let the researchers investigate the inheritance of the wild-boar-type pattern and the local activity of pigmentation genes, although most of the large genetic association dataset came from domestic pigs.

MC1R and KIT were linked to whether stripes appeared

A genome-wide association study, or GWAS, searches many inherited DNA variants across a population to find genomic regions that occur more often with a particular trait. In the 931 piglets retained for the association analysis after quality control, the strongest suggestive signals lay on pig chromosomes 6 and 8, close to two well-known pigmentation genes: MC1R and KIT.

MC1R is part of the signalling system that helps pigment cells regulate the type and amount of melanin they produce, while KIT has an important role in the development and distribution of pigment-producing cells. Among the striped animals actually tested for the respective variants, the researchers found neither the specific MC1R insertion nor the KIT duplication. The variant tests involved smaller, partly distinct samples rather than every striped piglet in the broader study. However, some piglets without either mutation were still unstriped.

That distinction is important: the two variants may interfere with the juvenile stripe programme, but simply lacking them is not enough to create the pattern. When the researchers repeated the association analysis while accounting for these effects, another signal appeared on chromosome 8 near CORIN, pointing to additional genetic control.

TYRP1 gene expression was higher in dark stripes

The second part of the study asked a different question: once a piglet is striped, what makes neighbouring strips of skin produce different colours? The researchers collected paired samples from dark and light dorsal stripes on three two-day-old piglets and compared which genes were active.

The clearest pigment-related result involved TYRP1, a gene whose protein product contributes to production of dark eumelanin. Its gene expression was higher in dark-stripe skin than in adjacent light stripes. Other pigmentation genes, including OCA2, PMEL and DCT, also had higher expression in dark stripes. The differences therefore involved several components of pigment production, not just one isolated gene.

RNA sequencing shows which genes are being transcribed, but it does not by itself explain why their activity differs. The researchers therefore also used ATAC-seq, a method that identifies regions of DNA that are relatively open and accessible to regulatory proteins. Open chromatin can act as a signpost for DNA regions involved in switching nearby genes on or off.

An open DNA region may help control the local pattern

The ATAC-seq analysis identified an accessible region about 1.8 kilobases downstream of TYRP1. The region contained a predicted binding site for SOX10, a transcription factor involved in pigment-cell biology and the regulation of pigmentation genes. SOX10 gene expression was also higher in hair follicles from dark stripes. The authors therefore propose that local regulation around TYRP1 could help produce the contrast between dark and light stripes.

This is a candidate mechanism rather than a demonstrated genetic switch. The study did not functionally alter the proposed regulatory region to show that it causes the stripe difference, and the skin comparison involved only three newborn piglets. The authors describe the work as a preliminary molecular explanation that now needs direct functional testing.

Taken together, the results suggest that juvenile striping is controlled at more than one level. Some inherited variants, including changes involving MC1R and KIT, may prevent the stripe programme from appearing, while local regulation of genes such as TYRP1 may help determine why neighbouring skin regions become differently pigmented once the pattern is present.

Sources and image credit

Xiong, S., Cui, D., Xiao, S., Li, L., & Guo, Y. (2026). Unraveling porcine juvenile striping: insights from the integration of genomics, transcriptomics and ATAC-seq. BMC Genomics.Primary open-access research article published 25 September 2026. GWAS of 932 F2 pigs identified candidate regions involving MC1R and KIT, conditional analysis a locus near CORIN, and RNA-seq/ATAC-seq of dark/light juvenile stripes implicated TYRP1 expression and a putative SOX10-binding accessible region. Functional validation of the proposed regulatory mechanism remains needed.

Image: Juvenile wild boar (Sus scrofa) in the Palatinate Forest, Rhineland-Palatinate, Germany, 18 June 2014. Photo: Fischer.H / Wikimedia Commons. Representative image; not a study animal. · CC BY-SA 4.0 · Source

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