The positive effect of this management tool has been documented both in domestic and wild populations, although the long-term outcome can be difficult to evaluate, and some concerns exist that genetic rescue might lead to outbreeding depression. Increasing the genetic variability of small, isolated populations by the spontaneous or human-planned introduction of new individuals is often referred to as “genetic rescue”. Genetic Rescue in Domestic and Wild Populations Additional breeding among F2 crosses could therefore merit from further consideration in genetic rescue management.ġ.1. Our analyses demonstrate the benefits of outcrossing but indicate that some of the acquired genetic diversity is lost following immediate backcrossing.
We also found that runs of homozygosity, extended chromosomal regions of homozygous genotypes inherited from a common ancestor, were reduced in F2 individuals compared with Lundehund individuals. We predicted that genome-wide diversity in F2 dogs would be higher than in the Lundehund but lower than in the F1 and the Buhund, and the heterozygosity values showed the expected patterns. Conservation breeding decisions for the (typically) small number of outcrossed individuals are vital for managing the rescue process, and we genotyped the Lundehund ( n = 12), the Buhund ( n = 12), their crosses (F1, n = 7) and first-generation backcrosses to the Lundehund (F2, n = 12) with >170,000 single nucleotide polymorphism loci to compare their levels of genetic diversity.
An example is the Norwegian Lundehund, a small spitz dog with inbreeding-related health problems that is being crossed with three Nordic breeds, including the Norwegian Buhund. Augmenting the genetic diversity of small, inbred populations by the introduction of new individuals is often termed “genetic rescue”.
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