A pedigree-based analysis of mitochondrial DNA diversity in a dog population on the example of German Hovawarts

S. Zielińska,I. Głażewska

doi:10.5194/aab-58-335-2015

Abstract

Abstract. The purpose of the article is to illustrate the use of pedigree analysis to evaluate mtDNA diversity in a selected population of pedigree dogs, to describe the paths of mtDNA inheritance and to estimate the spread of potential pedigree errors or mutations that occurred in different generations of ancestors. Hovawart, old German breed, was used as an example. The number and frequencies of mtDNA haplotypes were calculated based on numbers of dam lines and their representatives. The scale of potential errors in calculations that can result from pedigree errors or from new mutations in ancestors from the 5th or 10th ancestral generation was evaluated. The analysis included 368 breeding bitches from four German kennel organizations. The bitches represented three dam lines, with the Ho1, Ho2 and HoU mtDNA haplotypes. Significant differences in the frequency of the haplotypes in the population, from 0.27 to 73.37 %, and among kennel organizations and regions of the country were recorded. Considerable differences in the scale of potential errors in calculations arising from mtDNA mutations or pedigree errors were noted between 0.27 and 28.69 %, depending on the number of representatives of the subline in which the error appeared and the generation taken into account in the simulations. The study revealed an interesting paradox: although the differences between the haplotypes are the result of events (mutations) from thousands of years ago, the number and the frequencies of the haplotypes in the population are the result of the modern history of the population and current breeding policy.

Highlights

In recent years, genetic diversity in dogs and health issues resulting from breeding policy have met with growing interest from researchers and breeders, and diversity of mitochondrial DNA is one of the issues discussed
The analysis included 368 breeding bitches from kennels belonging to the German breeding organizations Rassezuchtverein für Hovawart-Hunde (RZV) (226 females), Hovawart Zuchtgemeinschaft Deutschland (HZD) (90 females), and Hovawart-Club (HC) (13 females) associated in the Verband für das Deutsche Hundewesen (VDH), and from kennels belonging to Spezialzuchtgemeinschaft der Hovawartzüchter Mitteldeutschlands (SZG) (39 females)
The bitches represented three dam lines that descend from Dina (Geisler), born before 1925, Dina (Brüser), born in 1923, and Wasser (Tewe) born in 1924

Summary

Introduction

Genetic diversity in dogs and health issues resulting from breeding policy have met with growing interest from researchers and breeders, and diversity of mitochondrial DNA is one of the issues discussed. In the analyses of Polish Hounds and Hovawart dogs (Głazewska and Prusak, 2012; Głazewska et al, 2012), pedigree data were used to evaluate haplotype frequencies. The necessary conditions for such studies are credible pedigrees and the lack of mutations (Głazewska et al, 2013) because they lead to incorrect calculation results. The error frequency resulting from mutations is determined by the mutation rate of a given mtDNA region that is estimated on a scale of thousands of years, and, significantly exceeds the period described in the pedigrees of modern breeds of domestic animals. Heteroplasmy or new mutations are only occasionally reported in dog or horse studies

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