# Genomic analysis reveals convergent signatures of selection for milk traits in sheep and goats

## TL;DR

This study finds shared genetic signals in sheep and goats related to milk traits, revealing convergent evolution and potential targets for improving dairy production.

## Contribution

The study identifies convergent selection signals and species-specific genes influencing milk traits in sheep and goats, offering new targets for dairy breeding.

## Key findings

- Species-specific genes like POU2F1 in sheep and PRPF6 in goats are linked to milk traits.
- Common selection signals such as CLASP1 are found in both sheep and goats, indicating convergent evolution.
- Genes like CLASP1 are promising targets for improving milk production in dairy species.

## Abstract

Convergent evolution offers a unique lens through which to explore the molecular underpinnings of significant phenotypic transformations. Similar selective pressures likely drove the evolution of analogous milk traits in sheep and goats. Consequently, the current study aimed to identify common selection signals for milk traits across dairy and non-dairy breeds of sheep and goats worldwide.

In this study, a total of 308 whole-genome sequences from diverse sheep (n = 108) and goat (n = 200) breeds, including both dairy and non-dairy types, across the world were utilized. The population structure and genetic diversity of dairy and non-dairy sheep and goat breeds were characterized. Species-specific genes associated with milk traits, such as POU2F1, ABCD2, TRNAC-GCA in sheep and PRPF6, VPS13C, TPD52L2, NFX1 and B4GALT1 in goats, were identified. Further gene annotation and bioinformatics analyses indicated that different biological pathways are important for milk traits in each species: fatty acid oxidation and AMP metabolic process in sheep, the U2-type spliceosomal complex and propanoate metabolism in goats. Additionally, common signatures of selection such as CLASP1, PDS5B, ZNF831, CCDC73 were found in sheep and goats. Haplotype and transcriptional analyses further confirmed the role of these genes in milk production and provided evidence for their analogous evolution in sheep and goats. The CLASP1 gene was identified as a target of convergent selection, representing a promising candidate for genetic improvement programs in dairy species.

These results provide insights into the genetic basis of convergent dairy traits, offering valuable targets for improving milk production and advancing dairy sheep and goat breeding programs.

The online version contains supplementary material available at 10.1186/s40104-025-01334-2.