Opportunities of genomics for the use of semen cryo-conserved in gene banks
In a study published in July 2022 in Frontiers in Genetics (section Livestock Genomics), Kor Oldenbroek and Jack Windig of Wageningen University & Research (WUR), Animal Breeding and Genomics emphasize that gene banks are a sustainable and reliable archive of genetic diversity and explain how DNA information of cryo-conserved sires and from animals in the living populations can be combined.
Combining DNA information of cryo-conserved sires and from animals in the living populations
In their paper, the authors state that “genomic information has become the standard to be used for choices made in the conservation and utilization of farm animal genetic diversity”. They explain how DNA information of cryo-conserved sires and of animals in the living populations can be combined, and how this combination can be used to realize three goals: 1) to make the gene bank a more complete archive of genetic diversity, 2) to determine the history of the genetic diversity of living populations, and 3) to improve the performance and the genetic diversity of living populations.
Using genomic information to increase genetic diversity
Genomic information can, for example, help to ‘fine-tune’ the selection of animals in living populations for the sampling of their semen, oocytes, or embryos for cryo-conservation. Through the use of appropriately developed methods, selected animals can increase the genetic diversity of the samples of the species already conserved. To obtain a complete archive of the genetic diversity of a species of a breed, the analyzed genomic data should be as accurate as possible. This will guarantee that specific alleles or haplotypes are included in the cryo-collection.
In less controlled breeding programs, genetic drift (the change in frequency of existing gene variants in the population due to random chance) is a real risk. Due to drift or an intense selection, the loss of part of the genomes of founder animals in the present live populations will occur, in which case gene bank sires that contain parts can be used to re-introduce these parts of the genome and restore the genetic diversity in the living population.
Opportunities for stakeholders
Different stakeholders can benefit from genomic data that is stored in gene banks. Gene bank institutes can use genomics to prioritize breed lines and animals within breeds for conservation and to optimise the collections. They can also use the data to test animals for breed purity or for genomic selection. Similarly, rare breed associations can use genomics to re-use sires which genomes are no longer present in the populations, to monitor the relationship and inbreeding over generations, and to remove parts of the genome of other introgressed breeds. Finally, commercial breeding companies have the opportunity to use the genotypic and phenotypic data of gene bank sires into their reference populations for genomic selection, can re-use sires when parts of their genome are interesting (and no longer present in their current breeding sires), can monitor kinship and inbreeding over generations and can consider introgression of interesting genes of gene bank sires not present in their current breeding animals.