Lack of genetic diversity monitoring threatens rare breeds

Genetic diversity in the United Kingdom’s livestock breeds could have improved monitoring, as there are several rare breeds with no publicly available genetic data, research reveals.

Researchers reviewed previous studies and national records to assess what is known about the genetic health of UK livestock populations, including estimates of inbreeding and population size.

These findings could help guide future research priorities and inform conservation policy for rare livestock breeds across the UK.

The review identified 37 studies published between 1975 and 2024, covering a range of species from cattle and pigs to turkeys and geese. 

While genetic studies have been carried out on 42 per cent of the breeds on the Rare Breed Survival Trust’s (RBST) database, many species - including all UK turkey, duck, and geese rare breeds - lack genetic diversity estimates.

Data discrepancies

Experts at the Roslin Institute compared UK Government census-based diversity estimates with DNA-based measures of livestock diversity from peer-reviewed studies. Results reveal discrepancies between the estimates, with the census figures being generally higher. 

This discrepancy is likely due to the way census-based calculations assume all breeding animals contribute equally to the next generation — this assumption does not always hold true in managed livestock systems, where a small number of males may father most offspring, the team explains.

As a result, the genetic pool can be smaller than the headcount suggests, leaving populations more vulnerable to inbreeding and loss of rare traits.

Genetic diversity

The findings support improved monitoring of genetic diversity. Genetic diversity is essential for adapting to new environmental and disease challenges, and is also an international conservation obligation for the UK.

One example highlighted in the review is the Chillingham wild cattle, a herd which grazes in northern England with no human intervention. The genetic diversity levels of this breed were found to be lower than those of iconic endangered species such as pandas or cheetahs, with the most recent diversity estimates from over a decade ago. 

Studying such populations could shed light on how high levels of inbreeding affect long-term survival, the researcher team says.

Experts also call for more use of whole-genome sequencing to identify rare genetic variants that may contribute to valuable traits, such as resilience to specific climates or diseases, that could benefit farming in future.

Related links

Research publication 

Rare Breeds Survival Trust (RBST)

Image credit: Chillingham Wild Cattle Association.