Genetic diversity and population structure of Polish Arabian horses assessed through breeding and microsatellite data

Differences and changes: an evaluation of the genetic diversity of Arabian mares from Polish state studs born between 1996 and 2013

The goal of our study was to estimate genetic diversity of Arabian horses from Polish state studs which could have changed due to the extensive use of foreign sires in Polish breeding after 1989. The analysis focused on 1,388 Arabian mares born from 1996 to 2013 in the Białka, Janów Podlaski and Michałów studs. Basic parameters of pedigree, mitochondrial DNA and microsatellite analyses were considered in the study. In the pedigree analysis, changes in the gene pool over the years were noted through the considerable increase of contribution of new founders’ genes and the considerable decrease of inbreeding level. The microsatellite analysis confirmed progressive changes in the gene pool but, contrary to expectations, only three new microsatellite alleles were detected, and a decreased level of heterozygosity was observed. In turn, mtDNA analysis showed a stable genetic situation in the studs throughout the period analysed. The results of the analyses present a diverse picture of the population, which is clearly divided into the three subpopulations of Białka, Janów Podlaski and Michałów, although the pictures presented differed depending on the analytical methods used. Genetic differences among the studs should be considered a positive feature of the Polish population. In order to preserve the present level of population genetic diversity, changes in breeding policy are needed that aim to stop the loss of genes of the historical ancestors of Polish Arabian horses.

Genetic Variability Trend of Lusitano Horse Breed Reared in Italy

The Lusitano Horse (LH) originates from Portugal, but is reared worldwide. Since 1994, the University of Milan has routinely tested the LHs bred in Italy for parentage control. This study aims to assess the genetic variability of the LH reared in Italy using 16 microsatellites markers. Moreover, the genetic variability changes over the years in the total population (n.384) and in unrelated horses (n.47) were evaluated. Horses were grouped according to their date of birth (1975–1990, 1991–2000, 2001–2010, 2010–2019). Standard genetic diversity parameters, including observed (Ho) and expected (He) heterozygosity, Hardy-Weinberg equilibrium (HWE; P-Val), allelic richness, and inbreeding coefficient (Fis) were estimated. In the whole period, the total population showed Ho as high as 0.69, low Fis (0.057), and imbalance for HWE. When considering the unrelated horses, Ho was seen to increase over time (from 0.594 in 1975–1990 to 0.68 in 2010–2019) and frequencies were in HWE, again having low and decreasing values of Fis (from 0.208 in 1975–1990 to 0.019 in 2010–2019). Bottleneck analysis excluded a recent population decline. Principal Coordinate Analysis at the individual level defined two clusters, the major cluster including all the most recent horses. An increasing number of dams (156% more from 2001–2010 to 2011–2019) supports the good variability recorded in the population so far. However, the high number of foals (77.2%) sired by only four stallions in recent years suggests caution in the choice of the sires for the future.

Mitochondrial DNA Survey Reveals the Lack of Accuracy in Maremmano Horse Studbook Records

* Correspondence: andrea [...].