Researchers in China have discovered 32 genes associated with wool fineness across breeds of a sheep, setting the groundwork for molecular breeding programs.
The global push for more comfortable and lightweight clothes and fabrics has led to a need for higher quality wool, which is often defined by fibre fineness. But to date, this has proved a challenging target for sheep breeding programmes.
The team of scientists, led by Xue Pu at Xinjiang Normal University, began by analysing 45 female Ordos fine wool sheep, which are similar to Merino sheep, randomly selected from an animal husbandry company’s stock. They grouped hair samples into ‘fine’ and ‘course’ and then took skin tissue samples from 10 of each group for RNA sequencing. Thery also examined datasets on five other animals.
New insight from skin tissues
The work showed that common genes were clustered into eight ‘modules’, and both sheep and rabbits with the same wool types had similar gene expression patterns, while the reverse trend was seen for those with dissimilar hair. From this, the scientists concluded that gene expression in skin tissues is likely to influential the look and feel of hair on animals.
By further enriching RNA from the samples, they also found that an area they described as the brown module was particularly associated with hair follicle development, that was strongly correlated across species and breeds. However, they noted that further research is needed to establish which genes within the module have specific impact on fineness, which is the primary factor in determining the market value of wool.
Clues from evolution
Looking at the Ordos fine wool sheep, they identified “significant and highly expressed” 32 candidate genes which could potentially influence wool fineness. Finding such candidate genes has “significant implications for improving hair fineness and implementing molecular breeding strategies in sheep and other animal with woolly coats,” they said.
“These results provide evidence for a significant correlation, either positive or negative, between candidate gene expression and phenotype, thereby supporting their potential influence on wool fineness,” they wrote in the journal Frontiers in Genetics.
As well as the implications for molecular-assisted breeding, more broadly, the work sheds light on the origin and evolution of animal hair, they added.
