Researchers in the animal reproduction team at Invermay had noticed that late puberty was a family trait in their research flock.
A family tree search traced the trait back to a common grand-sire from the Davisdale line of Romneys.
The researchers had the entire genome of the sire and three of his sons sequenced and then began hunting for a gene variant that could be responsible for delayed puberty in their descendent ewes.
The search focused on 60 genes known to be involved in reproductive function, as well as growth and body composition, because these are also related to puberty onset.
The gene variants in the female descendants’ DNA were searched for and they matched their occurrence with age at puberty. They found a strong association between age of puberty and a naturally occurring gene variant.
The oldest ewes reaching puberty had inherited two copies of the leptin receptor gene variant. This was a new finding. Leptin is an important hormone for controlling fat deposition and regulating appetite.
The leptin receptor sits on the surface of cells, detecting and receiving the leptin hormone as it circulates through the body. The receptor is known to be associated with puberty onset in mice, humans, and cattle.
More work needs to be done before it is certain the variant is responsible for the late puberty onset.
The research has been published in the international academic journal Biology of Reproduction.
