Understanding the effects of the bovine POLLED variants

Area of Science:

• Genetics
• Developmental Biology
• Animal Science

Background:

• Horns in bovine species develop from a horn bud, with ossification occurring post-birth.
• Hornless (polled) traits exist across domestic bovids, with horn bud formation absent in these individuals.
• The genetic underpinnings of horn growth and polledness are not fully understood.

Purpose of the Study:

• To investigate the genetic pathways regulating horn development and the absence of horn buds in polled cattle.
• To identify genetic variants associated with polledness in cattle.
• To explore the regulatory mechanisms affected by polledness variants.

Main Methods:

• Histological examination of bovine fetal horn buds.
• Analysis of genetic variants for polledness on BTA1.
• Transcriptomic studies to assess gene and long non-coding RNA expression.
• Candidate gene expression analysis (e.g., RXFP2).

Main Results:

• Four intergenic genetic variants for polledness in cattle have been identified on BTA1.
• These variants likely affect the regulation of nearby genes or long non-coding RNAs.
• Reduced expression of RXFP2 was observed in the fetal horn buds of polled animals with the Celtic variant.

Conclusions:

• Polledness variants in cattle disrupt normal horn bud development.
• Understanding these genetic pathways can inform precision genome editing for polled cattle breeding.
• Further research is needed to confirm the role of long non-coding RNAs and candidate genes.