This study aims to examine the genetic structure and diversity levels of seven indigenous Greek horse breeds: Andravida, Pindos, Thessaly, Skyros, Penia, Messara and Rodos, using 15 microsatellites. Phenotypic traits were combined with factorial correspondence analyses to create two datasets: one “Baseline” containing typical samples, and one “Unknown” with non-typical or of disputed origin samples. In the Greek “Baseline” horses, 142 alleles were found. The mean observed and effective number of alleles, the polymorphism information content and the allelic richness were 6.75, 4.14, 0.63 and 5.12, respectively. The expected and observed heterozygosity and inbreeding coefficient varied between 0.81 and 0.29 and 0.79 and 0.24. The above dataset was enriched with data from 41 foreign horse breeds and 40 Przewalski samples to perform a breed assignment. The highest percentage of successfully assigned samples was for Skyros, Messara and Rodos, with rates of 93%, 89% and 100%, respectively, suggesting their considerable homogeneity, while Andravida, Pindos, Thessaly and Penia scored 32.5, 34.1, 44.0 and 45.7%, respectively. Structural analysis confirmed the results of FCA and showed the genetic similarities of the above breeds. The results revealed the influence of foreign breeds (mainly Garrano, Turkoman, Irish Draft, Hanoverian and Belgian Draft). There is an urgent need to implement management measures for the pure homogeneous breeds and selection strategies for the remaining breeds which are genetically similar.

Timor ponies (TP) were first shipped to Australia in the early 1800s and were highly valued as transport and pack animals, which resulted in TPs contributing to the development of Australian horse breeds. Today, while the exact number of TPs in Australia is currently unknown, there has been recent interest in establishing a domestic breeding program for Australian TPs. The aim of this study was to evaluate the relatedness of a sample of TPs, as well as provide estimates of genomic inbreeding levels to better inform the feasibility of using these animals as founders for a domestic breeding program. Hair samples from each horse were genotyped using the Illumina 80K Infinium Equine genotyping array and data were analysed using PLINK v1.90b7, KING 2.3.2 and R v4.3.1. The results illustrate that there are distantly related and minimally inbred horses within the sampled TPs. Lengths of the ROH segments also indicated that recent inbreeding events are likely to only have occurred in a third of the horses. Overall, these results are promising for the success of a domestic TP breeding program; however, considering the low number of domestic TPs known to reside in Australia, there would certainly still be substantial benefits to incorporating additional TPs either directly from Timor or from areas in Australia that are believed to contain wild descendants of TPs.

To our knowledge this study was the first to analyze the genetic variability of Nigerian horses through genetic markers. Genetic variation in 15 microsatellite loci was examined in 31 Nigerian horses and high levels of genetic variation were observed. The values were similar to those found in Barb horses from Morocco and Algeria.

The history and population dynamics of feral horse and wild mustang population in the Western United States has led to diverse populations of disparate ancestry. These iconic populations are currently managed by the Bureau of Land Management (BLM) and their genetic history is of great interest for both management and conservation purposes. We examined population genetic parameters using 12 well established microsatellite loci in nearly 8,500 horses representing 235 populations sampled across more than 20 years. Samples were collected by BLM or by members of other management agencies from 10 states. Genetic variability and genetic resemblance to domestic horse breeds using multiple methods were estimated. A wide range of variation levels were observed across the populations. In general, within-population variability was slightly lower than what has been found in domestic horse breeds, but still retains diversity. As expected, levels of population variation correlated to census size. Several populations were sampled longitudinally with intervals between sampling of about 5 years. For these longitudinal samples, there was no trend towards an increase or decline in diversity, indicating consistent management practices. Relationships between populations and domestic breeds ranged from close association to one or two specific breeds to extreme divergence of the feral horses to all breeds examined. Reasons for divergence are mainly related to the founding of the population and subsequent demographic history. Overall, there was a slight tendency for geographically close feral populations to be more similar to each other than to more distant populations. The results of this study show the feral horse populations in the western US have a considerable variation, though management practices can strongly influence variability levels.

In this study, we analyzed microsatellite variation in DNA obtained from hair samples collected from 46 local Greek horse populations originating from the islands of Skyros (Skyros Small Horse; n=9), Rhodes (Rodos Small Horse; n=6), Lesvos (with the traditional miniature Midili Small Horse (n=2) and the larger Lesvos Gaiter (n=22)) and Crete (Messara) (n=7). We used 15 autosomal microsatellite markers (VHL20, HTG4, AHT4, HMS7, HTG6, AHT5, HMS6, ASB2, HTG10, HTG7, HMS3, HMS2, ASB17, ASB23 and LEX33) for the genetic characterization of the above populations and exploration of their genetic structure and diversity levels. A total of 120 alleles were detected across the 15 loci with a minimum of 4 alleles in HTG7 locus and a maximum of 13 alleles in ASB17 locus. Τhe total per population number of alleles was 42 (Skyros Small Horse), 20 (Rodos Small Horse), 71 (Lesvos Gaiter), 52 (Messara breed) and 21 (Midili Small Horse). The effective number of alleles (Ne) per locus ranged from 1.47±0.13 (Rodos Small Horse) to 4.67±0.31 (Lesvos Gaiter). The allelic richness (Ar) was between 1.50±0.12 (Rodos Small Horse) and 2.93±0.08 (Lesvos Gaiter) and the average Polymorphism Information Content (PIC) values varied from 0.200±0.035 (Rodos Small Horse) to 0.733±0.026 (Lesvos Gaiter). No significant deviations from H-W equilibrium were found except for three loci (ASB2, HTG10 and LEX33) in Messara and one locus (ASB23) in Lesvos Gaiter. Τhe inbreeding coefficient (Fis) ranged from -0.130 (Rodos Small Horse) to 0.042 (Lesvos Gaiter). The observed (Ho) and expected (He) multilocus heterozygosity mean estimations were highest in Lesvos Gaiter (0.764±0.027 and 0.783±0.024, respectively) and smallest in Rodos Small Horse (0.300±0.075 and 0.269±0.064, respectively). Across loci, the total genetic diversity HT was 0.741, the diversity among subpopulations HS was 0.621 and the multilocus genetic differentiation GST was 0.161, which was rather high. The population of Rodos Small Horse separated from the remaining horses as shown by factorial correspondence analysis, population assignment and metric multidimensional scaling diagrams. This study highlights the loss of genetic diversity in small isolated horse populations and the urgent need to take protective measures to preserve them.

The Y chromosome carries information about the demography of paternal lineages, and thus, can prove invaluable for retracing both the evolutionary trajectory of wild animals and the breeding history of domesticates. In horses, the Y chromosome shows a limited, but highly informative, sequence diversity, supporting the increasing breeding influence of Oriental lineages during the last 1500 years. Here, we augment the primary horse Y-phylogeny, which is currently mainly based on modern horse breeds of economic interest, with haplotypes (HT) segregating in remote horse populations around the world. We analyze target enriched sequencing data of 5 Mb of the Y chromosome from 76 domestic males, together with 89 whole genome sequenced domestic males and five Przewalski’s horses from previous studies. The resulting phylogeny comprises 153 HTs defined by 2966 variants and offers unprecedented resolution into the history of horse paternal lineages. It reveals the presence of a remarkable number of previously unknown haplogroups in Mongolian horses and insular populations. Phylogenetic placement of HTs retrieved from 163 archaeological specimens further indicates that most of the present-day Y-chromosomal variation evolved after the domestication process that started around 4200 years ago in the Western Eurasian steppes. Our comprehensive phylogeny significantly reduces ascertainment bias and constitutes a robust evolutionary framework for analyzing horse population dynamics and diversity.

Introduction: Spontaneous rupture of tendons and ligaments is common in several species including humans. In horses, degenerative suspensory ligament desmitis (DSLD) is an important acquired idiopathic disease of a major energy-storing tendon-like structure. DSLD risk is increased in several breeds, including the Peruvian Horse. Affected horses have often been used for breeding before the disease is apparent. Breed predisposition suggests a substantial genetic contribution, but heritability and genetic architecture of DSLD have not been determined. Methods: To identify genomic regions associated with DSLD, we recruited a reference population of 183 Peruvian Horses, phenotyped as DSLD cases or controls, and undertook a genome-wide association study (GWAS), a regional window variance analysis using local genomic partitioning, a signatures of selection (SOS) analysis, and polygenic risk score (PRS) prediction of DSLD risk. We also estimated trait heritability from pedigrees. Results: Heritability was estimated in a population of 1,927 Peruvian horses at 0.22 ± 0.08. After establishing a permutation-based threshold for genome-wide significance, 151 DSLD risk single nucleotide polymorphisms (SNPs) were identified by GWAS. Multiple regions of enriched local heritability were identified across the genome, with strong enrichment signals on chromosomes 1, 2, 6, 10, 13, 16, 18, 22, and the X chromosome. With SOS analysis, there were 66 genes with a selection signature in DSLD cases that was not present in the control group that included the TGFB3 gene. Pathways enriched in DSLD cases included proteoglycan metabolism, extracellular matrix homeostasis, and signal transduction pathways that included the hedgehog signaling pathway. The best PRS predictive performance was obtained when we fitted 1% of top SNPs using a Bayesian Ridge Regression model which achieved the highest mean of R 2 on both the probit and logit liability scales, indicating a strong predictive performance. Discussion: We conclude that within-breed GWAS of DSLD in the Peruvian Horse has further confirmed that moderate heritability and a polygenic architecture underlies the trait and identified multiple DSLD SNP associations in novel tendinopathy candidate genes influencing disease risk. Pathways enriched with DSLD risk variants include ones that influence glycosaminoglycan metabolism, extracellular matrix homeostasis, signal transduction pathways.

The process of forming a genealogical structure in the Vyatka breed makes it relevant to assess its differentiation at the genetic level. As a result of testing 293 Vyatka horses at 17 DNA microsatellite loci, 136 alleles were identified (Ae = 4.11. Ho = 0.726) and the genetic differentiation of ten lines was assessed for a number of indicators, including the fixation index Fst (0.011–0.134). Sequencing of the mtDNA D-loop region (530 bp) showed the presence of 11 haplogroups with a high level of haplotype variability in family lines. The high level of genetic differentiation of the genealogical structure of the Vyatka horse breed is a prerequisite for successful work to preserve this unique small population.

A total of 229 Arabian horse hair samples including 120 samples from El-Zahraa stud and 89 from two private farms in addition to 20 hair samples of Dutch Warmblood were genotyped by 16 microsatellite markers. The purposes of this study were; firstly, to investigate the current status of the genetic diversity and inbreeding of Arabian horse populations reared in Egypt. Secondly, to examine the traditional maternal based strain classification system "Al Khamsa" using samples of native Arabian horses reared in the El-Zahraa stud based on 16 microsatellite markers. El-Zahraa stud showed high inbreeding (F-IS = 0.110) and should be corrected by modifying mating system through avoiding excessive use of certain sires in breeding program. Across the five basic strains of the Arabian horse, nine loci showed 13 private alleles with the Seglawi recorded six and the Abeyan recorded no private alleles. The highest Nei genetic distance and pairwise F-ST values were recorded between Abeyan and Hamdani while the lowest were recorded between Kehilan and Seglawi. The cluster pattern of the individual phylogenetic tree and STRUCTURE plots of the five basic horse strains indicate that there was no sharp demarcation between those five strains, and the influence of the dame line and the traditional maternal lines classification of the El-Zahraa Arabian horses was unclear. The results of this study confirm the applicability and efficiency of these 16 STR markers for assessing genetic diversity but not in examining the traditional maternal based strain classification system using native Arabian horses from Egypt.

The Y chromosome is a valuable genetic marker for studying the origin and influence of paternal lineages in populations. In this study, we conducted Y-chromosomal lineage-tracing in Arabian horses. First, we resolved a Y haplotype phylogeny based on the next generation sequencing data of 157 males from several breeds. Y-chromosomal haplotypes specific for Arabian horses were inferred by genotyping a collection of 145 males representing most Arabian sire lines that are active around the globe. These lines formed three discrete haplogroups, and the same haplogroups were detected in Arabian populations native to the Middle East. The Arabian haplotypes were clearly distinct from the ones detected in Akhal Tekes, Turkoman horses, and the progeny of two Thoroughbred foundation sires. However, a haplotype introduced into the English Thoroughbred by the stallion Byerley Turk (1680), was shared among Arabians, Turkomans, and Akhal Tekes, which opens a discussion about the historic connections between Oriental horse types. Furthermore, we genetically traced Arabian sire line breeding in the Western World over the past 200 years. This confirmed a strong selection for relatively few male lineages and uncovered incongruences to written pedigree records. Overall, we demonstrate how fine-scaled Y-analysis contributes to a better understanding of the historical development of horse breeds.

This is a follow-up study to validate the previously detected association of the FKBP6 gene with stallion subfertility. Using a select cohort of 150 Thoroughbred stallions with detailed breeding records, we confirm significant association (P < 0.0001) between low per-cycle pregnancy rates (≤50%) and a combined A/A-A/A genotype of SNPs chr13:11 353 372G>A and chr13:11 353 436A>C in FKBP6 exon 5. We also show that stallion subfertility and the combined genotype A/A-A/A are not associated with the level of genetic diversity based on 12 autosomal microsatellite markers, or with pedigree-based inbreeding rate, or the extent of contribution of a leading Thoroughbred sire, Northern Dancer, in a stallion's pedigree. We develop a TaqMan allelic discrimination assay for the two SNPs to facilitate accurate and high-throughput genotyping. We determine allele, genotype and combined genotype frequencies of FKBP6 exon 5 SNPs in a global cohort of 518 Thoroughbreds (76% stallions or geldings and 24% mares) and show that the frequency of the A/A-A/A genotype is 4%. Because there is no similar association between the FKBP6 exon 5 genotype and stallion subfertility in Hanoverians, we suggest that the two SNPs are not causative but rather tagging a breed-specific haplotype with genetic variants unique to Thoroughbreds. Further WGS-based research is needed to identify the molecular causes underlying the observed genotype-phenotype association in Thoroughbred stallions.

Abstract STRUCTURE remains the most applied software aimed at recovering the true, but unknown, population structure from microsatellite or other genetic markers. About 30% of structure‐based studies could not be reproduced (Molecular Ecology, 21, 2012, 4925). Here we use a large set of data from 2,323 horses from 93 domestic breeds plus the Przewalski horse, typed at 15 microsatellites, to evaluate how program settings impact the estimation of the optimal number of population clusters K opt that best describe the observed data. Domestic horses are suited as a test case as there is extensive background knowledge on the history of many breeds and extensive phylogenetic analyses. Different methods based on different genetic assumptions and statistical procedures (dapc, flock, PCoA, and structure with different run scenarios) all revealed general, broad‐scale breed relationships that largely reflect known breed histories but diverged how they characterized small‐scale patterns. structure failed to consistently identify K opt using the most widespread approach, the ΔK method, despite very large numbers of MCMC iterations (3,000,000) and replicates (100). The interpretation of breed structure over increasing numbers of K, without assuming a K opt, was consistent with known breed histories. The over‐reliance on K opt should be replaced by a qualitative description of clustering over increasing K, which is scientifically more honest and has the advantage of being much faster and less computer intensive as lower numbers of MCMC iterations and repetitions suffice for stable results. Very large data sets are highly challenging for cluster analyses, especially when populations with complex genetic histories are investigated.

The Cleveland Bay (CB) is the United Kingdom's oldest established horse breed. In this study we analyzed the genetic variability in CB horses and investigated its genetic relationships with other horse breeds. We examined the genetic variability among 90 CB horses sampled in the USA compared to a total of 3447 horses from 59 other breeds. Analysis of the genetic diversity and population structure was carried out using 15 microsatellite loci. We found that genetic diversity in CB horses was less than that for the majority of other tested breeds. The genetic similarity measures showed no direct relationship between the CB and Thoroughbred but suggested the Turkman horses (likely in the lineage of ancestors of the Thoroughbred) as a possible ancestor. Our findings reveal the genetic uniqueness of the CB breed and indicate its need to be preserved as a genetic resource.

The Estonian Native Horse (ENH) is a medium-size pony found mainly in the western islands of Estonia and is well-adapted to the harsh northern climate and poor pastures. The ancestry of the ENH is debated, including alleged claims about direct descendance from the extinct Tarpan. Here we conducted a detailed analysis of the genetic makeup and relationships of the ENH based on the genotypes of 15 autosomal short tandem repeats (STRs), 18 Y chromosomal single nucleotide polymorphisms (SNPs), mitochondrial D-loop sequence and lateral gait allele in DMRT3. The study encompassed 2890 horses of 61 breeds, including 33 ENHs. We show that the expected and observed genetic diversities of the ENH are among the highest within 52 global breeds, and the highest among 8 related Northern European ponies. The genetically closest breeds to the ENH are the Finn Horse, and the geographically more distant primitive Hucul and Konik. ENH matrilines are diverse and relate to draught and Pontic-Caspian breeds. ENH patrilines relate to draught breeds, and to a unique haplogroup not described before. None of the 33 ENHs carried the “gait” mutation, but the mutation was found in 2 Huculs. The study demonstrates that the ENH is a genetically distinct and diverse breed of ancient origin with no notable pressure of selective breeding.

Feral horses in Theodore Roosevelt National Park (TRNP) represent an iconic era of the North Dakota Badlands. Their uncertain history raises management questions regarding origins, genetic diversity, and long-term genetic viability. Hair samples with follicles were collected from 196 horses in the Park and used to sequence the control region of mitochondrial DNA (mtDNA) and to profile 12 autosomal short tandem repeat (STR) markers. Three mtDNA haplotypes found in the TRNP horses belonged to haplogroups L and B. The control region variation was low with haplotype diversity of 0.5271, nucleotide diversity of 0.0077 and mean pairwise difference of 2.93. We sequenced one mitochondrial genome from each haplotype determined by the control region. Two complete mtDNA sequences of haplogroup L were closely related to the mtDNA of American Paint horse. The TRNP haplotype B did not have close matches in GenBank. The phylogenetic test placed this sequence in a group consisting of two horses from China, one from Yakutia, and one from Italy raising a possibility of historical transportation of horses from Siberia and East Asia to North America. Autosomal STR loci were polymorphic and indicated that the TRNP horses were distinctly different from 48 major horse breeds. Heterozygosity, mean number of alleles, and other measures of diversity indicated that TRNP herd diversity was below that observed for most other feral herds and domestic breeds. Both mtDNA and STRs demonstrated that the existing genetic data sets of horses are insufficient to determine the exact origins of the TRNP horses. However, measures of nuclear and mitochondrial diversity have elucidated management needs. It is recommended that new genetic stock be introduced and that adaptive management principles are employed to ensure that unique mitochondrial lineages are preserved and genetic diversity is increased and maintained over time.

Additional file 1: Table S1. List of animals included in the study. This table provides detailed information about identification, pedigree, phenotypes and genotypes of animals included in the study. The full pedigree is also provided. Table S2a. Details on markers and haplotypes in the mapped region. This table provides markers and their position, including the KRT25 variant along ECA11. Colors are used to depict haplotypes, assuming 18 founder haplotypes (12 “non-curly” haplotypes carried by crossbreed animals as well as the six most frequent other haplotypes, including one “curly” haplotype). Haplotypes are given for each animal, according to pedigree data. Table S2b. Delineation of the critical mapping region by haplotype analysis. Haplotypes were sorted out according to their sequence and the associated coat phenotype. Critical recombination events are easily detected by color changes and help identify the upper and lower bounds of the mapping interval. Table S3. PCR primers used to genotype candidate genes. This table provides detailed information about chromosome positions, alleles, gene names, ID, primer sequences, fragment lengths and Tm. Table S4. Statistics on genome-wide detection of functional variants. Table S4 provides statistics on variant detection based on NGS sequencing, with numbers of new and known variants (whole genome and genes) according to their consequence as predicted by VEP. Positional candidate variants are also reported. Table S5. List of gene variants predicted to impact protein functionality. Table S5 includes chromosome positions, alleles, gene ID and functional annotations. The last column (Existing variation) indicates variants; which were already known in dbSNP. Table S6. Concordant variants identified in the critical mapping interval. Table S6 includes chromosome positions, alleles, functional annotations and gene ID for concordant variants. Table S7. Horses genotyped by PCR and Sanger sequencing. Horse names, phenotype and genotype for the KRT24:g.21932167G>T, Top2A:g.22186465C>T and Top2A: g.22191762G>T variants are presented. Table S8. Pedigree information for the progeny of Walker’s Prince T and Dravkvallons Ite O Maguzu. Table S8 provides pedigree and phenotype data obtained from breeders and the Curly horse pedigree database ( http://www.curlyhorses.info/mainsearch.asp ). Table S9. Comparison of NCBI and Ensembl annotations within the keratin cluster on ECA11. Annotation features are listed along ECA11, from position 2,136,900 to 2,197,100 pb; some discrepancy is observed upstream of the critical mapping interval.

A previous study revealed a strong association between the DMRT3:Ser301STOP mutation in horses and alternate gaits as well as performance in harness racing. Several follow-up studies have confirmed a high frequency of the mutation in gaited horse breeds and an effect on gait quality. The aim of this study was to determine when and where the mutation arose, to identify additional potential causal mutations and to determine the coalescence time for contemporary haplotypes carrying the stop mutation. We utilized sequences from 89 horses representing 26 breeds to identify 102 SNPs encompassing the DMRT3 gene that are in strong linkage disequilibrium with the stop mutation. These 102 SNPs were genotyped in an additional 382 horses representing 72 breeds, and we identified 14 unique haplotypes. The results provided conclusive evidence that DMRT3:Ser301STOP is causal, as no other sequence polymorphisms showed an equally strong association to locomotion traits. The low sequence diversity among mutant chromosomes demonstrated that they must have diverged from a common ancestral sequence within the last 10 000 years. Thus, the mutation occurred either just before domestication or more likely some time after domestication and then spread across the world as a result of selection on locomotion traits.

BACKGROUND:Curly horses present a variety of curl phenotypes that are associated with various degrees of curliness of coat, mane, tail and ear hairs. Their origin is still a matter of debate and several genetic hypotheses have been formulated to explain the diversity in phenotype, including the combination of autosomal dominant and recessive alleles. Our purpose was to map the autosomal dominant curly hair locus and identify the causal variant using genome-wide association study (GWAS) and whole-genome sequencing approaches.RESULTS:A GWAS was performed using a Bayesian sparse linear mixed model, based on 51 curly and 19 straight-haired French and North American horses from 13 paternal families genotyped on the Illumina EquineSNP50 BeadChip. A single strong signal was observed on equine chromosome 11, in a region that encompasses the type I keratin gene cluster. This region was refined by haplotype analysis to a segment including 36 genes, among which are 10 keratin genes (KRT-10, -12, -20, -23, -24, -25, -26, -27, -28, -222). To comprehensively identify candidate causal variants within all these genes, whole-genome sequences were obtained for one heterozygous curly stallion and its straight-haired son. Among the four non-synonymous candidate variants identified and validated in the curly region, only variant g.21891160G>A in the KRT25 gene (KRT25:p.R89H) was in perfect agreement with haplotype status in the whole pedigree. Genetic association was then confirmed by genotyping a larger population consisting of 353 horses. However, five discordant curly horses were observed, which carried neither the variant nor the main haplotype associated with curliness. Sequencing of KRT25 for two discordant horses did not identify any other deleterious variant, which suggests locus rather than allelic heterogeneity for the curly phenotype.CONCLUSIONS:We identified the KRT25:p.R89H variant as responsible for the dominant curly trait, but a second dominant locus may also be involved in the shape of hairs within North American Curly horses.

The Polish Primitive Horse (PPH, Konik) is a Polish native horse breed managed through a conservation program mainly due to its characteristic phenotype of a primitive horse. One of the most important goals of PPH breeding strategy is the preservation and equal development of all existing maternal lines. However, until now there was no investigation into the real genetic diversity of 16 recognized PPH dam lines using mtDNA sequence variation. Herein, we describe the phylogenetic relationships between the PPH maternal lines based upon partial mtDNA D-loop sequencing of 173 individuals. Altogether, 19 mtDNA haplotypes were detected in the PPH population. Five haplotypes were putatively novel while the remaining 14 showed the 100% homology with sequences deposited in the GenBank database, represented by both modern and primitive horse breeds. Generally, comparisons found the haplotypes conformed to 10 different recognized mtDNA haplogroups (A, B, E, G, J, M, N, P, Q and R). A multi-breed analysis has indicated the phylogenetic similarity of PPH and other indigenous horse breeds derived from various geographical regions (e.g., Iberian Peninsula, Eastern Europe and Siberia) which may support the hypothesis that within the PPH breed numerous ancestral haplotypes (found all over the world) are still present. Only in the case of five maternal lines (Bona, Dzina I, Geneza, Popielica and Zaza) was the segregation of one specific mtDNA haplotype observed. The 11 remaining lines showed a higher degree of mtDNA haplotype variability (2-5 haplotypes segregating in each line). This study has revealed relatively high maternal genetic diversity in the small, indigenous PPH breed (19 haplotypes, overall HapD = 0.92). However, only some traditionally distinguished maternal lines can be treated as genetically pure. The rest show evidence of numerous mistakes recorded in the official PPH pedigrees. This study has proved the importance of maternal genetic diversity monitoring based upon the application of molecular mtDNA markers and can be useful for proper management of the PPH conservation program in the future.

We evaluated Ictidomys tridecemlineatus for sexual dimorphism by taking 40 skeletal measurements from 267 specimens from Texas, New Mexico, and Oklahoma. We compared measurements from males and females using discriminant-function analysis with included analyses of variance. Males and females were significantly different overall. Of the nine characters that were significantly different, eight were larger in males, while females had a greater sacrum width.