Genetic diversity of a large set of horse breeds raised in France assessed by microsatellite polymorphism

Abstract

The genetic diversity and structure of horses raised in France were investigated using 11 microsatellite markers and 1679 animals belonging to 34 breeds. Between-breed differences explained about ten per cent of the total genetic diversity (Fst = 0.099). Values of expected heterozygosity ranged from 0.43 to 0.79 depending on the breed. According to genetic relationships, multivariate and structure analyses, breeds could be classified into four genetic differentiated groups: warm-blooded, draught, Nordic and pony breeds. Using complementary maximisation of diversity and aggregate diversity approaches, we conclude that particular efforts should be made to conserve five local breeds, namely the Boulonnais, Landais, Merens, Poitevin and Pottok breeds.

Genetic diversity and admixture among Canadian, Mountain and Moorland and Nordic pony populations

“…The H o was highest at 0.770 in the Kerry Bog and lowest in the Exmoor at 0.569. These results are consistent with other published studies, in which fewer loci or a smaller sample size were used, for several populations including the Connemara, Fjord, Haflinger, Newfoundland, Standardbred and Sable Island (Luís et al, 2007;Plante et al, 2007;Leroy et al, 2009). In contrast, others have also found slightly higher values in the Connemara, Exmoor, Fell, Icelandic, Shetland, New Forest and Caspian (Cothran, 2004;Luís et al, 2007;Leroy et al, 2009).…”

“…These results are consistent with other published studies, in which fewer loci or a smaller sample size were used, for several populations including the Connemara, Fjord, Haflinger, Newfoundland, Standardbred and Sable Island (Luís et al, 2007;Plante et al, 2007;Leroy et al, 2009). In contrast, others have also found slightly higher values in the Connemara, Exmoor, Fell, Icelandic, Shetland, New Forest and Caspian (Cothran, 2004;Luís et al, 2007;Leroy et al, 2009). F IS varied from 0.1291 in the Sable Island and 0.0883 in the Exmoor to 20.1215 in the Kerry Bog, indicating that there is a high deficiency in heterozygotes in the Sable Island and Exmoor populations, whereas there is an excess of heterozygotes in the Kerry Bog population.…”

“…Although, there was no specific evidence for the presence of null alleles in any of the loci tested, deviations from the HWE varied from zero loci in the Canadian, Highland, New Forest, Shetland, Standardbred and Welsh populations to as high as 13 loci in the Sable Island population (P < 0.05). Deviations from HWE have been reported previously in small populations (such as the Hucul, Icelandic, Jaca Navarra and Pottok), or populations that are highly inbred, and may explain the deviations seen in the Sable Island herd (Solis et al, 2005;DeAssis et al, 2009;Leroy et al, 2009). The excess homozygosity observed could also be a result of genetic drift, nonrandom mating, substructure or small effective population size.…”

“…These characteristics make microsatellite loci particularly useful for estimating genetic diversity and characterizing breeds, which are necessary for developing good and viable conservation strategies (Achmann et al, 2004;Glowatzki-Mullis et al, 2006;Eggert et al, 2010). Recently, Leroy et al (2009) have reported that pony breeds tended to cluster distinctly and separately from horse breeds using 11 microsatellites to estimate genetic diversity in 34 French equine populations. European pony breeds (Connemara, Camargue, Landais, New Forest, Poney Français de Selle, Pottok and Welsh) clustered closely to Nordic pony breeds (Shetland, Icelandic and Fjord), but separately from both warmblood and coldblood horse breeds (Leroy et al, 2009).…”

“…Recently, Leroy et al (2009) have reported that pony breeds tended to cluster distinctly and separately from horse breeds using 11 microsatellites to estimate genetic diversity in 34 French equine populations. European pony breeds (Connemara, Camargue, Landais, New Forest, Poney Français de Selle, Pottok and Welsh) clustered closely to Nordic pony breeds (Shetland, Icelandic and Fjord), but separately from both warmblood and coldblood horse breeds (Leroy et al, 2009). Despite this, large studies involving the estimation of genetic diversity of solely pony breeds have not been performed, and studies available today tend to focus only on a few breeds or compare a large number of horse breeds with only a few pony breeds; this may not be the best way to measure the genetic diversity in pony breeds (Plante et al, 2007;Behl et al, 2008;Leroy et al, 2009).…”