Genetic variability of Akhal-Teke horses bred in Italy

Abstract

BackgroundThe Akhal-Teke horse (AKH) is native of the modern Turkmenistan area. It was introduced in Italy from 1991 to 2000 mainly as an endurance horse. This paper characterizes the genetic variability of the whole Italian AKH horse population and evaluates their inbreeding level by analyzing microsatellite markers and mitochondrial D-Loop sequences.MethodsSeventeen microsatellite marker loci were genotyped on 95 DNA samples from almost all the AKH horses bred in Italy in the last 20 years. Standard genetic variability measures (Ho, He, FIS) were compared against the same variables published on other eight AKH populations. In addition, 397 bp of mtDNA D-loop region were sequenced on a sub-group of 22 unrelated AKH out of the 95 sampled ones, and on 11 unrelated Arab horses. The haplotypes identified in the Italian population were aligned to sequences of AKH (56), Arab (five), Caspian Pony (13), Przewalskii (two) and Barb (15) horses available in GenBank. The Median Joining Network (MJN), Principal Component Analysis (PCA) and Neighbor-joining (NJ) tree were calculated on the total 126 sequences.ResultsNucleic markers showed a high degree of polymorphism (Ho = 0.642; He = 0.649) and a low inbreeding level (FIS = 0.016) in Italian horses, compared to other AKH populations (ranged from −0.103 AKH from Estonia to 0.114 AKH from Czech Republic). High variability was also recorded in the D-Loop region. 11 haplotypes were identified with haplotype diversity (hd), nucleotide diversity (π) and average number of nucleotide differences (k) of 0.938, 0.021 and 6.448, respectively. When all the 126 D-Loop sequences were compared, 51 haplotypes were found, and four were here found only in the Italian AKH horses. The 51 haplotypes were conformed to eight recognized mtDNA haplogroups (A, C, F, G, L, M, P and Q) and confirmed by MJN analysis, Italian horses being assigned to five haplogroups (A, C, G, L and M). Using a PCA approach to the same data, the total haplotypes were grouped into two clusters including A+C+M+P and G+F haplogroups, while L and Q haplogroups remained ungrouped. Finally, the NJ algorithm effectively discretizes only the L haplogroup. All the above data univocally indicate good genetic variability and accurate management of the Akhal-Teke population in Italy.

Unlocking Horse Y Chromosome Diversity

“…Recently, many studies have been focused on the loss of biodiversity [ 23 , 24 , 25 ] or the increase in deleterious genotypes [ 26 ] caused by such inbreeding (as reviewed in [ 7 ]). In the last 200 years, the inbreeding practice led to the phenotypical expression at homozygous sites of deleterious variants [ 27 ], as highlighted when the coefficients are calculated in order to evaluate the genetic diversity among different horse breeds [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 ,…”

Genome-wide single-nucleotide polymorphism data and mitochondrial hypervariable region 1 nucleotide sequence reveal the origin of the Akhal-Teke horse

“…The Akhal-Teke horse is one of the oldest and most famous horse breeds. It is now mainly distributed in Turkmenistan [ 2 ]. Most of the horses have golden chestnut hair, sometimes black or brown.…”

“…Today, the Akhal-Teke horse population is slowly declining and is endangered. Currently, the Akhal-Teke is found mainly in Turkmenistan [ 2 ].…”

Genetic Variability Trend of Lusitano Horse Breed Reared in Italy

“…In this regard, STR HTG7 is worthy of attention. A low number of alleles in HTG7 (four to six alleles) was recorded in local populations as Akhal-Teke [ 12 , 28 ], Lithuanian Horse [ 7 ], Polish Konig Horse [ 29 ], Colonial Spanish Horse [ 30 ], and Sanfratellano Horse [ 8 ] and in a cosmopolitan breed such as Thoroughbred (four alleles) [ 13 , 31 ]. Additionally, in the present study, HTG7 showed a low number of alleles (from a minimum of four to a maximum of six in the different groups) and a decrease in frequencies of some alleles along the time from the first (1975–90) to the last period (2010–19).…”

“…The genetic variability of the LH using pedigree data and STR markers has been described in several studies [ 1 , 2 , 3 , 5 , 6 ]. STR markers have been widely used to analyze the genetic diversity and population structure of other both cosmopolitan and local horse breeds [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. STRs are used worldwide for routine equine genotyping applied to forensics, parentage, and kinship analysis [ 14 , 15 ].…”