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Genomic selection for recovery of original genetic background from hybrids of endangered and common breeds.

Amador C, Hayes BJ, Daetwyler HD - Evol Appl (2013)

Bottom Line: This results in genetic admixture that can be undesirable when it challenges the genetic integrity of wild and domestic populations, causing a loss in special characteristics or unique genetic material and ultimately extinction.Both strategies were capable of identifying segment origin, and both removed up to the 100% of the Poll Dorset segments.While the selection process led to substantial inbreeding, we controlled it by imposing a minimum number of individuals contributing to the next generation.

View Article: PubMed Central - PubMed

Affiliation: INIA Madrid, Spain.

ABSTRACT
Critically endangered breeds and populations are often crossed with more common breeds or subspecies. This results in genetic admixture that can be undesirable when it challenges the genetic integrity of wild and domestic populations, causing a loss in special characteristics or unique genetic material and ultimately extinction. Here, we present two genomic selection strategies, using genome-wide DNA markers, to recover the genomic content of the original endangered population from admixtures. Each strategy relies on the estimation of the proportion of nonintrogressed genome in individuals based on a different method: either genomic prediction or identification of breed-specific haplotypes. Then, breeding programs that remove introgressed genomic information can be designed. To test these strategies, we used empirical 50K SNP array data from two pure sheep breeds, Merino (used as target breed), Poll Dorset and an existing admixed population of both breeds. Sheep populations with varying degrees of introgression and admixture were simulated starting from these real genotypes. Both strategies were capable of identifying segment origin, and both removed up to the 100% of the Poll Dorset segments. While the selection process led to substantial inbreeding, we controlled it by imposing a minimum number of individuals contributing to the next generation.

No MeSH data available.


Proportion of Merino recovered (upper panels) after one or five generations of management and ΔF (lower panels) after one or five (cumulative ΔF) generations of management using the haplotype approach for five or 20 generations of admixture (40 individuals contributing).
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fig05: Proportion of Merino recovered (upper panels) after one or five generations of management and ΔF (lower panels) after one or five (cumulative ΔF) generations of management using the haplotype approach for five or 20 generations of admixture (40 individuals contributing).

Mentions: Results obtained when doubling the number of contributing individuals to 40 (haplotype approach) for five generations of admixture are shown in Fig. 5 (left). The proportion of Merino recovered in these simulations was considerably lower for one generation of breeding, due to the smaller selective pressure. Consequently, the method requires the five generations of breeding to achieve the maximum recovery but with a smaller increase in inbreeding.


Genomic selection for recovery of original genetic background from hybrids of endangered and common breeds.

Amador C, Hayes BJ, Daetwyler HD - Evol Appl (2013)

Proportion of Merino recovered (upper panels) after one or five generations of management and ΔF (lower panels) after one or five (cumulative ΔF) generations of management using the haplotype approach for five or 20 generations of admixture (40 individuals contributing).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927885&req=5

fig05: Proportion of Merino recovered (upper panels) after one or five generations of management and ΔF (lower panels) after one or five (cumulative ΔF) generations of management using the haplotype approach for five or 20 generations of admixture (40 individuals contributing).
Mentions: Results obtained when doubling the number of contributing individuals to 40 (haplotype approach) for five generations of admixture are shown in Fig. 5 (left). The proportion of Merino recovered in these simulations was considerably lower for one generation of breeding, due to the smaller selective pressure. Consequently, the method requires the five generations of breeding to achieve the maximum recovery but with a smaller increase in inbreeding.

Bottom Line: This results in genetic admixture that can be undesirable when it challenges the genetic integrity of wild and domestic populations, causing a loss in special characteristics or unique genetic material and ultimately extinction.Both strategies were capable of identifying segment origin, and both removed up to the 100% of the Poll Dorset segments.While the selection process led to substantial inbreeding, we controlled it by imposing a minimum number of individuals contributing to the next generation.

View Article: PubMed Central - PubMed

Affiliation: INIA Madrid, Spain.

ABSTRACT
Critically endangered breeds and populations are often crossed with more common breeds or subspecies. This results in genetic admixture that can be undesirable when it challenges the genetic integrity of wild and domestic populations, causing a loss in special characteristics or unique genetic material and ultimately extinction. Here, we present two genomic selection strategies, using genome-wide DNA markers, to recover the genomic content of the original endangered population from admixtures. Each strategy relies on the estimation of the proportion of nonintrogressed genome in individuals based on a different method: either genomic prediction or identification of breed-specific haplotypes. Then, breeding programs that remove introgressed genomic information can be designed. To test these strategies, we used empirical 50K SNP array data from two pure sheep breeds, Merino (used as target breed), Poll Dorset and an existing admixed population of both breeds. Sheep populations with varying degrees of introgression and admixture were simulated starting from these real genotypes. Both strategies were capable of identifying segment origin, and both removed up to the 100% of the Poll Dorset segments. While the selection process led to substantial inbreeding, we controlled it by imposing a minimum number of individuals contributing to the next generation.

No MeSH data available.