The Relation between Canine Hip Dysplasia, Genetic Diversity and Inbreeding by Breed

Frank H Comhaire

doi:10.4236/ojvm.2014.45008

Abstract

Objectives: To assess the relation between the prevalence of canine hip dysplasia, inbreeding and genetic diversity by breed. Methods: Retrospective pedigree analysis of 9 breeds based on a reference population of 41,728 individuals, and hip dysplasia assessment in 1745 dogs. Results: Hip dysplasia was less common among breeds with higher coefficient of inbreeding, lower genetic diversity, and highest contribution of one single ancestor to the population. Inbreeding not exceeding 3.25% should be considered safe since it will maintain a sufficiently high genetic diversity within the breed. Clinical Significance: Together with published data on single breeds, the present findings question the general assumption that line-breeding or in-breeding has an adverse effect on the prevalence of hip dysplasia. Hip assessment is indicated in all breeds, but better methods are needed for selecting dogs suitable for reproduction.

Highlights

A high degree of inbreeding increases the probability of homozygosity of recessive genes, and enhances the risk of hereditary diseases coming to expression
In 9 of these breeds hip dysplasia was assessed by the experts of the National Committee for Inherited Skeletal Disorders [9] according to the categorical scoring method recommended by the Fédération Cynologique Internationale (FCI) [10] in the time period between 2006 and 2010
There was a tendency to negative correlation (P < 0.1) between the proportion of dogs with Canine hip dysplasia (CHD) and the mean Norberg angles (NA) (r = −0.62), and between the coefficient of inbreeding (COI) and the CHD breed average score (r = −0.57)

Summary

Introduction

A high degree of inbreeding increases the probability of homozygosity of recessive genes, and enhances the risk of hereditary diseases coming to expression. Inbreeding decreases the genetic diversity, and the degree of inbreeding will increase from one generation to the if genetic diversity is low. Information is lacking as to the degree of inbreeding that is still safe for healthy breeding. Canine hip dysplasia (CHD) is related to single nucleotide polymorphisms in a relatively large number of quantitative trait loci [1]. This genetic trait may cause degenerative join disease through multifactorial mechanisms, including inflammation, oxidative overload and, probably, epigenetic changes [2]. It would be expected that the prevalence of CHD by breed should increase if genetic diversity is low, and the degree of inbreeding is

Objectives

Methods

Results

Discussion

Conclusion