Genetic Rescue of the Highly Inbred Norwegian Lundehund

Abstract

Augmenting the genetic diversity of small, inbred populations by the introduction of new individuals is often termed “genetic rescue“. 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. 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. 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. 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. Our analyses demonstrate the benefits of outcrossing but indicate that some of the acquired genetic diversity is lost following immediate backcrossing. Additional breeding among F2 crosses could therefore merit from further consideration in genetic rescue management.

Special Issue: “Canine Genetics 2”

“…The Norwegian Lundehund breed is characterized by extreme inbreeding and several disease predispositions that are hypothesized to result from inbreeding depression. Melis et al report on a genetic rescue experiment that uses introgression of the phenotypically similar Norwegian Buhund in an attempt to increase genetic diversity in the Norwegian Lundehund [27]. The African painted dog (Lycaon pictus) is a highly endangered wild canid species.…”

Gut microbiome dysbiosis is associated with host genetics in the Norwegian Lundehund

“…Currently, the breed counts more than 1,500 individuals, which all descend from these five dogs. For this reason, the Lundehund has an extremely low level of heterozygosity, which is around 5% as estimated by high-density SNP arrays ( Melis et al, 2022 ), and an effective population size of only 13 individuals ( Melis et al, 2013 ; Kropatsch et al, 2015 ). The low genetic diversity is associated with low fertility and with high rates of a protein-losing enteropathy localized to the small intestine, often reported as the Lundehund syndrome, but also as intestinal lymphangiectasia and IBD ( Berghoff et al, 2007 ).…”

“…All dogs included in the project were screened for hip dysplasia and hereditary ocular pathologies before including them in breeding. We previously analyzed the genetic diversity of the parental, F1, and F2 animals from the Lundehund x Buhund outcross and found a restoration of genetic diversity through outcrossing, with F1 animals having highest diversity ( Melis et al, 2022 ). The mean heterozygosity (estimated from 8,184 linkage-disequilibrium-pruned loci) of Lundehund, F1 and F2 dogs was 0.043, 0.272 and 0.153, respectively ( Melis et al, 2022 ).…”

“…We previously analyzed the genetic diversity of the parental, F1, and F2 animals from the Lundehund x Buhund outcross and found a restoration of genetic diversity through outcrossing, with F1 animals having highest diversity ( Melis et al, 2022 ). The mean heterozygosity (estimated from 8,184 linkage-disequilibrium-pruned loci) of Lundehund, F1 and F2 dogs was 0.043, 0.272 and 0.153, respectively ( Melis et al, 2022 ). None of the F1 and F2 progeny has, so far, developed Lundehund syndrome.…”

Človek, žival: poglavja o njunih soočanjih

“…Zaradi pasemskih standardov se je pri nekaterih pasmah psov uveljavilo kupiranje repov in uhljev pri mladičih, kar je v Sloveniji prepovedano od leta 2007 z Zakonom o zaščiti živali (ZZZiv-UPB3, UL RS 38/13 z dopolnitvami). V izogib kupiranju repov je genetik in rejec bokserjev Dr. Bruce Cattanach leta 1992 v Veliki Britaniji s križanjem kratkorepe bokserke s kratkorepim valižanskim ovčarjem razvil linijo kratkorepih (bobtail) bokserjev z dominantnim genom za to lastnost(Melis, Pertoldi, Ludington 2022, Cattanach 1996.Tudi pri ovcah in prašičih najdemo različne dolžine repov. Pri dolgorepih ovcah je ponavadi prisotnih od 16 do 18 repnih vretenc (tudi do 24), pri kratkorepih pa nekje med 8 in 10 vretenc, tudi manj (Dýrmundsson in Niżnikowski 2010).…”