Cross-Breeding Is Inevitable to Conserve the Highly Inbred Population of Puffin Hunter: The Norwegian Lundehund

Abstract

The Norwegian Lundehund is a highly endangered native dog breed. Low fertility and high frequency predisposition to intestinal disorder imply inbreeding depression. We assessed the genetic diversity of the Lundehund population from pedigree data and evaluated the potential of optimal contribution selection and cross-breeding in the long-term management of the Lundehund population. The current Norwegian Lundehund population is highly inbred and has lost 38.8% of the genetic diversity in the base population. Effective population size estimates varied between 13 and 82 depending on the method used. Optimal contribution selection alone facilitates no improvement in the current situation in the Lundehund due to the extremely high relatedness of the whole population. Addition of (replacement with) 10 breeding candidates of foreign breed to 30 Lundehund breeders reduced the parental additive genetic relationship by 40–42% (48–53%). Immediate actions are needed to increase the genetic diversity in the current Lundehund population. The only option to secure the conservation of this rare breed is to introduce individuals from foreign breeds as breeding candidates.

Genetic rescue of an endangered domestic animal through outcrossing with closely related breeds: A case study of the Norwegian Lundehund

“…This is in accordance with recommendations based on analyses of Lundehund pedigrees [33] that show extremely high relatedness of individuals within the breed. The results suggest that each candidate breed may contribute genetic diversity for different local regions within chromosomes, which could augment the long-term effect of the genetic rescue.…”

Deleterious alleles in the context of domestication, inbreeding, and selection

“…Moreover, artificial selection for specific traits sometimes results in so much inbreeding that it is threatening the survival of the breed. Clear examples can be seen in dogs such as the Norwegian Lundehund suffering from intestinal problems, but cancer, eye, and heart diseases are also common (Kettunen, Daverdin, Helfjord, & Berg, ; Schoenebeck & Ostrander, ). Combined, these effects of inbreeding in domestics have led to animals and plants that may have lost their ability to face environmental challenges, should they come from climate change or new diseases.…”

Examination of the efficacy of small genetic panels in genomic conservation of companion animal populations

“…This result has important implications for the preservation of domestic dog breeds. Most academic effort in the field of genetic diversity management over the past few decades has primarily been focused on optimal management for small populations of conservation concern where mating in the entire population can be controlled (Ballou & Lacy, 1995;Fernández, Toro, & Caballero, 2001, 2004Kettunen, Daverdin, Helfjord, & Berg, 2017;López-Cortegano et al, 2019;Sonesson & Meuwissen, 2001). Similarly, in livestock, conservation of genomic diversity in combination with genomic selection can occur at the level of entire herds or regional populations, though also suffers from geographic partitioning and localization of conservation efforts (Bosse et al, 2015;Bruford et al, 2015;Herrero-Medrano et al, 2014;Ramljak et al, 2018;Zhao et al, 2019).…”

“…Genetic diversity in many common domestic dog breeds has been declining systematically since the beginning of the 1800's, when modern breeding practices came into fashion (Jansson & Laikre, 2018). As such, inbreeding in domestic dog breeds is substantial and widespread (Freedman et al, 2014;Kettunen, Daverdin, Helfjord, & Berg, 2017;Pedersen, Pooch, & Liu, 2016;Sams & Boyko, 2018) and has led to an increase in recessive deleterious mutations of high effect (Jagannathan et al, 2019;Marsden et al, 2016) as well as general inbreeding depression (Chu et al, 2019). Dog breeders and breed clubs are increasingly aware of the serious consequences of diversity loss, and with robust panels of both microsatellite markers and genome-wide SNP arrays widely available commercially, there is great potential for breeders to use genetic testing in ways that ultimately improve (or worsen) genetic diversity.…”