Absence of Rare Alleles in Commercial Chickens

by 5m Editor
13 November 2008, at 10:17a.m.

US - The findings of a study conducted by Texas A&M University indicate that there are three main factors impacting the genetic composition of commercial chickens: breed utilisation, genetic improvement and industry consolidation.

Consequently, the question arises - "Is there sufficient genetic diversity within industry stocks to address future needs?"

It is now possible to address biodiversity using a previously unattainable metric: missing alleles or genes. To achieve this assessment, 2551 informative SNPs (single-nucleotide polymorphisms) were genotyped on 2580 individuals, including 1440 commercial birds.

The proportion of missing alleles in commercial populations was assessed by (1) estimating the global SNP allele frequency distribution, using a hypothetical ancestral population as a reference, then determining the portion of the distribution lost, and then (2) determining the relationship between allele loss and the inbreeding coefficient.

The results: 50% or more of the genetic diversity in ancestral breeds is absent in commercial pure lines. The missing genetic diversity resulted from the limited number of incorporated breeds.

It is established that SNP weights act as sentinels of biodiversity and provide an objective assessment of the strains that are most valuable for preserving genetic diversity. This is the first experimental analysis investigating the extant genetic diversity of virtually an entire agricultural commodity.

The methods presented are the first to characterize biodiversity in terms of allelic diversity and to objectively link rate of allele loss with the inbreeding coefficient.

Further Reading

- You can view the full study by clicking here.

5m Editor