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Scientific Reports: HOX Genes Shape Sheep Tail Length
2 Mar 2026
Study shows embryonic HOX gene expression patterns persist in adult sheep tails and influence tail length via vertebral number differences.
Body axis patterning in vertebrates is established during embryogenesis by HOX genes, whose expression gradients define spatial identity along the anterior–posterior axis.
In this study, Improved Jezersko–Solčava sheep were used to investigate whether these developmental signatures persist in adulthood. Animals segregating for tail length and HOXB13 promoter variants revealed strong genotype–phenotype associations. The HOXB13 genotype emerged as the main determinant of adult tail length by influencing caudal vertebral number. RNA-seq and qPCR analyses identified a clear anterior–posterior HOXB13 expression gradient in adult tail skin and bone tissues, with stronger distal expression in short-tailed animals.
These findings provide in vivo evidence that embryonic positional identity can be retained as transcriptional signatures in adult tissues.