A putative autosomal gene increasing ovulation rate in Romney sheep

Area of Science:

• Animal Genetics
• Reproductive Biology
• Sheep Breeding

Background:

• Romney sheep flocks exhibit a history of high prolificacy.
• Understanding genetic factors influencing ovulation rates is crucial for sheep breeding programs.

Purpose of the Study:

• To investigate the genetic basis of high ovulation rates in a specific Romney sheep flock.
• To identify and characterize a potential major gene affecting prolificacy.

Main Methods:

• Ovulation rates were measured in 547 progeny from 24 rams.
• Statistical analysis was used to identify segregation patterns suggestive of a major gene.
• Inheritance patterns were analyzed to determine the mode of gene action.

Main Results:

• A segregating major gene, designated FecW, was identified, influencing ovulation rates.
• FecW appears to be autosomal, with one copy increasing ovulation rate by 0.8-1.0 eggs.
• The phenotype associated with FecW differs from previously described prolificacy genes in sheep.

Conclusions:

• A novel autosomal major gene (FecW) significantly increases ovulation rates in Romney sheep.
• Unlike some other prolificacy genes, FecW does not appear to cause infertility in homozygous ewes.
• FecW offers a potential new tool for genetic selection to improve sheep prolificacy.