Genetic relationship between the Nordestino horse and national and international horse breeds

Abstract

ABSTRACT. Knowledge of genetic diversity and relationships between breeds is very important for conservation programs. Hair samples were collected from 393 individual Nordestino horses and genotyped using 14 microsatellite markers in order to investigate the genetic relationship between this breed and 66 international horse breeds. There was high allelic diversity and inbreeding coefficient within population values were not significant, which was probably due to crossbreeding. Despite the Nordestino horse population being in Hardy-Weinberg equilibrium, a global deficit of heterozygotes was observed. This may represent evidence of repeated use of the same stallions for breeding, which is consistent with the high number of castrated males found. Campolina, Mangalarga Marchador, and Mangalarga were the Brazilian horse breeds most closely related to the Nordestino horse, which is a reflection of recent introgressions. Among Iberian horse breeds, the Sorraia breed appears to have had an important influence on the genetics of the Nordestino horse. Those results provide important information that can guide future conservation programs.

Genetic Diversity, Population Structure and Phylogenetic Relationship of Race, Sports, Draft, and Wild Type Horses

“…The results of phylogenetic analysis revealed that wild horses were in separate cluster while Draft horses were found much closer to Wild horses, whereas Race horses were found at maximum far distant from Wild horses. Results of the present study are in accordance with Pires et al (2016) who formed a dendrogram of 68 breeds of horse, and reported racing and wild breeds far apart in neighbor joining tree. While Bowling et al (2003) reported that due to an extra chromosome it is difficult to relate directly wild horses with domestic horse breeds.…”

“…Likewise, Berber et al (2014) also observed this highly polymorphic locus with number of alleles 14. All the markers under study were also analyzed by Pires et al (2016) and found ASB17 most polymorphic marker in Nordestino horses while most heterozygous locus was AHT4. Maximum observed heterozygosity was found at ASB17 for all the studied categories, other study reports that AHT4 is most heterozygous loci among Spanish Celtic breeds of horses (Canon et al, 2001).…”

Major inconsistencies of inferred population genetic structure estimated in a large set of domestic horse breeds using microsatellites

“…Variation in mtDNA control region sequences gives a clear example of this crossbreeding. Phylogenetic trees typically resulted in low bootstrap values and thus low statistical support irrespective of tree‐building and distance algorithms (Conant et al, 2012; Cothran & Luís, 2005; Pires et al, 2016). An epiphenomenon of the highly complex genetic basis appears to be the lack of a clear separation of breeds at low K and the lack of breed separation of breed membership coefficients at very high K .…”

“…Most studies of horses that have utilized STRUCTURE have examined a small number of breeds, often from a specific geographic locality (Barcaccia et al, 2013; Berber et al, 2014; Bömcke, Gengler, & Cothran, 2011; Conant et al, 2012; Cothran et al, 2011; Galov et al, 2013; Janova et al, 2013; Khanshour, Conant, et al, 2013; Khanshour et al, 2015; Koban et al, 2012; Kusza et al, 2013; Lopes et al, 2015; Mackowski, Mucha, Cholewinski, & Cieslak, 2015; Mujica, 2006; Pablo Gómez et al, 2017; Pires et al, 2016; Prystupa, Juras, Cothran, Buchanan, & Plante, 2012; Rendo, Iriondo, Manzano, & Estonba, 2012; Sereno, Sereno, Vega‐Pla, Kelly, & Bermejo, 2008; Tozaki et al, 2003; Uzans, Lucas, McLeod, & Frasier, 2015). The ∆ K obtained in these studies appeared reasonable for the number of breeds.…”

“…The large variety of breed management is exemplified by the co‐existence of closed breeds without admixture from outside breeds, open breeds, landraces, and feral populations with little artificial selection but sometimes strong natural selection such as the adaptation to high altitudes (Hendrickson, 2013), and breeds with strong artificial selection for desired traits. Two large microsatellite studies investigated 67 and 41 breeds, respectively, and constructed distance‐based phylogenies using a variety of phylogenetic methods (Conant, Juras, & Cothran, 2012; Pires et al, 2016). In general, these approaches revealed patterns largely reflecting known breed histories, but statistical support was consistently low (Cothran & Luís, 2005).…”