Rapid genetic diversification within dog breeds as evidenced by a case study on Schnauzers

Abstract

As a result of strong artificial selection, the domesticated dog has arguably become one of the most morphologically diverse vertebrate species, which is mirrored in the classification of around 400 different breeds. To test the influence of breeding history on the genetic structure and variability of today's dog breeds, we investigated 12 dog breeds using a set of 19 microsatellite markers from a total of 597 individuals with about 50 individuals analysed per breed. High genetic diversity was noted over all breeds, with the ancient Asian breeds (Akita, Chow Chow, Shar Pei) exhibiting the highest variability, as was indicated chiefly by an extraordinarily high number of rare and private alleles. Using a Bayesian clustering method, we detected significant genetic stratification within the closely related Schnauzer breeds. The individuals of these three recently differentiated breeds (Miniature, Standard and Giant Schnauzer) could not be assigned to a single cluster each. This hidden genetic structure was probably caused by assortative mating owing to breeders' preferences regarding coat colour types and the underlying practice of breeding in separate lineages. Such processes of strong artificial disruptive selection for different morphological traits in isolated and relatively small lineages can result in the rapid creation of new dog types and potentially new breeds and represent a unique opportunity to study the evolution of genetic and morphological differences in recently diverged populations.

Histiocytic sarcoma in 14 miniature schnauzers – a new breed predisposition?

“…Schnauzers are not part of this cluster, but rather belong to a cluster with Doberman pinschers (Parker , Streitberger et al . ). While Dobermans were not over‐represented in this study population, they have been previously reported to be at increased risk for HS (Kerlin & Hendrick ).…”

Studies of modern Italian dog populations reveal multiple patterns for domestic breed evolution

“…The natural canine attributes of visual and olfactory acuity (Chen, Irwin, & Zhang, 2012;Tacher et al, 2005), speed and endurance (Huson et al, 2012;Kemp, Bachus, Nairn, & Carrier, 2005;Pasi & Carrier, 2003), guardianship, predatory nature (Akkad et al, 2015;Starling, Branson, Thomson, & McGreevy, 2013;Sundman, Johnsson, Wright, & Jensen, 2016), and their seemingly innate companionability with humans (Cagan & Blass, 2016;Fadel et al, 2016;Gacsi, McGreevy, Kara, & Miklosi, 2009;vonHoldt et al, 2017;Jakovcevic, Elgier, Mustaca, & Bentosela, 2010;van der Waaij, Wilsson, & Strandberg, 2008) have been exploited for thousands of years. However, in the pursuit of a distinct lineage, selection of breeding animals will unavoidably rely on a small source pool (Alam et al, 2012;Calboli, Sampson, Fretwell, & Balding, 2008;Kumpulainen et al, 2017;Pfahler & Distl, 2015;Streitberger et al, 2012;Wijnrocx et al, 2016). As such, dog breeds which perform similar tasks are frequently more closely related to each other than to breeds with different occupations, allowing for the visualization of phylogenetic breed clades sometimes segregating by broad behavior patterns (Parker et al, 2017;Vaysse, et al 2011;von Holdt et al, 2010;Parker et al, 2004;and Figure 2).…”

Genetic characterization of four native Italian shepherd dog breeds and analysis of their relationship to cosmopolitan dog breeds using microsatellite markers

“…Based on available breed histories, the majority of existing dog breeds were developed in the 19th century. At present, more than 400 canine breeds are registered worldwide by the Federation Cynologique Internationale (FCI, World Canine Organisation) and other federations such as the American and British Kennel Clubs (Parker et al, 2004;Streitberger et al, 2011).…”

“…Based on available breed histories, the majority of existing dog breeds were developed in the 19th century. At present, more than 400 canine breeds are registered worldwide by the Federation Cynologique Internationale (FCI, World Canine Organisation) and other federations such as the American and British Kennel Clubs (Parker et al, 2004;Streitberger et al, 2011).To understand the effect of breed structure on the genomic makeup of the dog, molecular markers can be put to use in both small and large data sets. Autosomal microsatellites have been utilized to study genetic diversity in several dog breeds, primarily for the purposes of determining the power of exclusion for parentage applications (Altet et al, 2001;DeNise et al, 2004).…”