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Topic:Lineage
Lineage in horses refers to the genetic heritage and ancestry that influence a horse's characteristics, performance, and breeding value. It encompasses the study of pedigrees, genetic markers, and inheritance patterns to understand traits passed from one generation to the next. Lineage analysis is utilized in breeding programs to enhance desirable traits such as speed, endurance, temperament, and conformation. This topic includes investigations into the genetic diversity within horse populations, the impact of selective breeding, and the identification of genetic disorders. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of lineage studies in equine genetics and breeding strategies.
Genetic characterization of horse bone excavated from the Kwakji archaeological site, Jeju, Korea. We determined the nucleotide sequences of the hypervariable D-loop region of mitochondrial DNA (mtDNA) from horse bone (humerus, A.D. 700 to A.D. 800) that was excavated from the Kwakji archaeological site, Jeju, Korea. We compared them with ones from extant horses. We designed three pairs of oligonucleotide primers from the tRNA-Thr and tRNA-Phe gene regions of mtDNA that are highly conserved among many other animal species. We cloned 232, 336, and 644 bp from the horse bone in order to determine the mtDNA D-loop sequence. The sequence was 1,124 bp long; the middle contained 19 tandem repeats...
History of Lipizzan horse maternal lines as revealed by mtDNA analysis. Sequencing of the mtDNA control region (385 or 695 bp) of 212 Lipizzans from eight studs revealed 37 haplotypes. Distribution of haplotypes among studs was biased, including many private haplotypes but only one haplotype was present in all the studs. According to historical data, numerous Lipizzan maternal lines originating from founder mares of different breeds have been established during the breed's history, so the broad genetic base of the Lipizzan maternal lines was expected. A comparison of Lipizzan sequences with 136 sequences of domestic- and wild-horses from GenBank showed a clusterin...
Phylogenetic relationships of Argentinean Creole horses and other South American and Spanish breeds inferred from mitochondrial DNA sequences. South American horses constitute a direct remnant of the Iberian horses brought to the New World by the Spanish conquerors. The source of the original horses was Spain, and it is generally assumed that the animals belonged to the Andalusian, Spanish Celtic, Barb or Arabian breeds. In order to establish the relationship between Argentinean and Spanish horses, a portion of the mitochondrial D-loop of 104 animals belonging to nine South American and Spanish breeds was analysed using SSCP and DNA sequencing. The variability found both within and between breeds was very high. There were 61 polymorp...
History and integrity of thoroughbred dam lines revealed in equine mtDNA variation. Mitochondrial DNA (mtDNA) D-loop sequences (381 bp) from 100 thoroughbreds in 19 of the most common matrilineal female families were used to reconstruct a founder female population for the thoroughbred ( approximately 1650-1750 AD). Seventeen haplotypes were found to have contributed to the 19 female lineages. In order to place the reconstructed founder population in wider historical context, we examined, using both single strand conformation polymorphism and direct sequence analysis, variation in a 343 bp mtDNA fragment in that population and 13 other horse populations of disparate provenance...
Mitochondrial DNA and the origins of the domestic horse. The place and date of the domestication of the horse has long been a matter for debate among archaeologists. To determine whether horses were domesticated from one or several ancestral horse populations, we sequenced the mitochondrial D-loop for 318 horses from 25 oriental and European breeds, including American mustangs. Adding these sequences to previously published data, the total comes to 652, the largest currently available database. From these sequences, a phylogenetic network was constructed that showed that most of the 93 different mitochondrial (mt)DNA types grouped into 17 distinct p...
Daily treatment of horses with equine somatotropin from 4 to 16 months of age. Fourteen foals between 4 and 4.5 mo of age were used to determine the effects of 12 mo of daily treatment with equine somatotropin (eST) on growth, metabolic, and hormonal characteristics. The foals were paired by sex, type, and lineage, and one of each pair was administered eST daily at 20 microg/kg of BW. Body weights, body measurements, and assessments of glucose tolerance and feedback effects on endogenous somatotropin (ST) secretion were made routinely. Treatment with eST did not alter (P > 0.10) BW, height at withers, length of body, widths of chest and rump, heart girth, length of he...
Microsatellite diversity, pedigree relatedness and the contributions of founder lineages to thoroughbred horses. The thoroughbred (TB) horse is one of the oldest breeds of domestic animals, with pedigree records spanning three centuries. Because the population is essentially closed, there is concern about loss of genetic variation. Here we report two parallel analyses. In the first, genetic variation in the current population is measured using data from 13 microsatellite loci in 211 horses with relationships calculated based on allele sharing. In the second analysis, pedigree information is used to calculate genetic relationships between animals based on shared ancestry. These two measures of relationshi...
Breed demarcation and potential for breed allocation of horses assessed by microsatellite markers. Population demarcation of eight horse breeds was investigated using genotype information of 306 horses from 26 microsatellite loci. The breeds include the indigenous Norwegian breeds Fjord Horse, Nordland/Lyngen Horse, Døle Horse and Coldblooded Trotter together with Icelandic Horse, Shetland Pony, Standardbred and Thoroughbred. Both phylogenetic analysis and a maximum likelihood method were applied to examine the potential for breed allocation of individual animals. The phylogenetic analysis utilizing simple allele sharing statistics revealed clear demarcation among the breeds; 95% of the in...
Widespread origins of domestic horse lineages. Domestication entails control of wild species and is generally regarded as a complex process confined to a restricted area and culture. Previous DNA sequence analyses of several domestic species have suggested only a limited number of origination events. We analyzed mitochondrial DNA (mtDNA) control region sequences of 191 domestic horses and found a high diversity of matrilines. Sequence analysis of equids from archaeological sites and late Pleistocene deposits showed that this diversity was not due to an accelerated mutation rate or an ancient domestication event. Consequently, high mtDNA se...
Equine influenza vaccine efficacy: the significance of antigenic variation. To investigate the level of cross-protection induced by equine influenza H3N8 vaccines derived from different lineages, two studies have been carried out with ponies vaccinated with 'American-like' and 'European-like' vaccines and experimentally challenged with a European-like strain. The results demonstrated that equine influenza vaccines clearly protect against challenge with homologous virus if serum antibody titres are sufficiently high. On the other hand, protection is incomplete even when animals vaccinated with heterologous strains have comparative antibody levels. Nevertheless, the pro...
The horse homolog of congenital aniridia conforms to codominant inheritance. Anterior segment dysgenesis syndrome occurs frequently in Rocky Mountain horses and has two distinct ocular phenotypes: (1) large cysts originating from the temporal ciliary body or peripheral retina and (2) multiple anterior segment anomalies including ciliary cysts, iris hypoplasia, iridocorneal adhesions and opacification, nuclear cataract, and megalocornea. To determine if anterior segment dysgenesis syndrome is heritable in horses we performed ophthalmic examinations and collected pedigree information on horses (n = 516) in an extended Rocky Mountain horse pedigree. Logistic regressive se...
ITS-1 ribosomal DNA sequence variants are maintained in different species and strains of Echinococcus. This study investigated sequence heterogeneity in the first internal transcribed spacer (ITS-1) of ribosomal DNA within and among species and strains of Echinococcus. Different ITS-1 sequence variants exist in Echinococcus granulosus and Echinococcus multilocularis, which represent at least four evolutionary lineages: (1) a sheep strain-lineage of E. granulosus, (2) a sister lineage of a cervid and camel E. granulosus ITS-1 variants, (3) a lineage including the ITS-1 variants representing horse, bovine and camel strains of E. granulosus, as well as variants from E. multilocularis, Echinococcus...
A pedigree-based study of mitochondrial D-loop DNA sequence variation among Arabian horses. Through DNA sequence comparisons of a mitochondrial D-loop hypervariable region, we investigated matrilineal diversity for Arabian horses in the United States. Sixty-two horses were tested. From published pedigrees they traced in the maternal line to 34 mares acquired primarily in the mid to late 19th century from nomadic Bedouin tribes. Compared with the reference sequence (GenBank X79547), these samples showed 27 haplotypes with altogether 31 base substitution sites within 397 bp of sequence. Based on examination of pedigrees from a random sampling of 200 horses in current studbooks of the A...
Mitochondrial D-loop sequence variation among the 16 maternal lines of the Lipizzan horse breed. Mitochondrial DNA from 49 Lipizzan horses representing 16 maternal lines from the original stud at Lipica was used for SSCP analysis and DNA sequencing. The SSCP analysis of the 444 bp long fragment of the D-loop region extending from the tRNA(Pro) gene to the central conserved sequence block revealed three distinct groups of SSCP patterns. Both ends of the D-loop region (378 bp and 310 bp), which are considered as the most variable regions within the mammalian mitochondrial DNA, were sequenced. According to 49 polymorphic sites identified within the both parts of the D-loop region, the 16 mat...
Evolutionary history of MHC class I genes in the mammalian order Perissodactyla. We carried out an analysis of partial sequences from expressed major histocompatibility complex (MHC) class I genes isolated from a range of equid species and more distantly related members of the mammalian order Perissodactyla. Phylogenetic analysis revealed a minimum of six groups, five of which contained genes and alleles that are found in equid species and one group specific to the rhinoceros. Four of the groups contained only one, or very few sequences, indicating the presence of relatively nonpolymorphic loci, while another group contained the majority of the equid sequences identified. ...
[Associations between the coat color and the blood-group system D antigens in horses]. The study of the association between the coat-color variants and the blood-group system D antigens in the populations of two related trotter breeds (Orlov Trotter and Russian Trotter) showed the presence of three associations between these characters in the Orlov Trotter breed. In the populations of Russian trotters, these associations were not detected. Possible reasons for the formation and maintenance of these associations and the role of the selection for coat color in the differentiation of breeds by the frequencies of some system D antigens are discussed.
Phylogenetic relationships of Cheju horses to other horse breeds as determined by mtDNA D-loop sequence polymorphism. Historical records suggest that horses inhabiting the island of Cheju in Korea are descendants of Mongolian horses introduced in 1276. Other studies, however, suggest that horses may have been present on the island prior to the Mongolian introduction. To determine the origin of the Cheju horses we used a phylogenetic analysis of sequences of the mitochondrial DNA (mtDNA) D-loop region, including tRNA Pro and parts of tRNA thr and tRNA Phe sequences (1102-bp excluding the tandem repeat region). Maximum parsimony and neighbor-joining trees were constructed using sequences determined for seven Ch...
Heritability of recurrent exertional rhabdomyolysis in Thoroughbred racehorses. To determine the likely mode of inheritance and identify probable foundation horses for recurrent exertional rhabdomyolysis (RER) in Thoroughbred (TB) racehorses. Methods: 4 families of TB racehorses with a high prevalence of RER, consisting of 3 to 53 horses/family, were used to determine mode of inheritance. Sixty-two TB horses with RER and 34 control TB racehorses without RER were used to identify probable foundation horses for the RER trait. Methods: RER was diagnosed by a veterinarian and verified by detecting high serum creatine kinase activity. Pedigrees dating from 1930 for all horses ...
Mitochondrial control region and 12S rRNA variation in Przewalski’s horse (Equus przewalskii). Variation in the control region and the 12S rRNA gene of all surviving mitochondrial lineages of Przewalski's horse was investigated. Variation is low despite the present day population being descended from 13 individuals probably representing animals from three different regions of its range. Phylogenetic comparison of these sequences, with sequences for the domestic horse, does not resolve the ancestral status of either horse.
Tobiano spotting pattern in horses: linkage of To with AlA and linkage disequilibrium. In a study of 2,786 tobiano and non-tobiano horses involved in paint horse breeding programs throughout the United States, the inheritance of the tobiano color pattern gene was tracked in pedigrees using the tightly linked polymorphic albumin gene. The dominant tobiano allele (T(o)), which produces the tobiano spotting pattern in horses, was in coupling with both AIA and AIB alleles at the albumin locus. The frequency of the T(o):AIA linkage phase among all the homozygous tobiano horses in this study including offspring and parents (N = 127), was 0.08. The T(o):AIB linkage phase was the most f...
Extensive mtDNA diversity in horses revealed by PCR-SSCP analysis. The hypervariable D-loop region of mitochondrial DNA (mtDNA) was amplified with the polymerase chain reaction using total horse DNA samples. Analysis of single strand conformation polymorphism (SSCP) of denatured amplification products was carried out by native polyacrylamide (8%) gel electrophoresis followed by silver staining. As many as 15 distinct SSCP variants were revealed when screening a total of 78 maternally unrelated horses representing five different breeds. All breeds showed a high degree of polymorphism and the estimated probability (PImt) that two maternally unrelated individual...
Unusual D system inheritance in Anglo-Arab horse. An unusual D system phenogroup appeared in one family line of Anglo-Arab horse. This phenogroup probably originated from inheritance with an apparent absence of factors and was transmitted through successive generations.
Intrageneric amplification of horse microsatellite markers with emphasis on the Przewalski’s horse (E. przewalskii). Primer sequences flanking 13 microsatellite loci isolated from the domestic horse (E. caballus) were successfully used to amplify homologous loci in the Przewalski's horse (E. przewalskii). The results demonstrate that the level of polymorphism at all 13 loci in the Przewalski's horse was comparable to that in the domestic horse and the overall exclusion probability in the Przewalski's horse was calculated to be 0.9994. The results suggest that it should be possible to use E. caballus-derived microsatellite markers to provide parentage verification and additional valuable information to the ca...
An immunohistochemical study of an equine B-cell lymphoma. The tissues of an 8-year-old thoroughbred castrated male horse with equine lymphoma were examined immunohistochemically. Neoplastic masses were observed in the mediastinum, mesenteric lymph nodes, gastric mucosa and serosa, liver capsule, and spleen capsule with associated lymph nodes. Histopathologically, the neoplastic cells were seen to consist predominantly of a mixture of well differentiated small and large types. Immunohistochemically, the small lymphoid cells were MHC class IIlow+ and PanT- and the large lymphoid cells were MHC class IIhigh+ and PanT-. These findings revealed that the n...
Parentage testing and linkage analysis in the horse using a set of highly polymorphic microsatellites. Ten (TG)n positive clones, isolated from an equine genomic library and sequenced, contained 12-19 uninterrupted TG repeats. Primers for polymerase chain reaction (PCR) were synthesized and nine of these (TG)n loci (HTG7-15) were successfully amplified and utilized in this study together with five previously reported equine microsatellite loci (HTG2-6). The PCR products were analysed by polyacrylamide gel electrophoresis followed by automated laser fluorescence detection or autoradiography. All microsatellites showed polymorphism and stable Mendelian inheritance. Differences in microsatellite v...
Rare alleles, MHC and captive breeding. In recent years, more detailed genetic information has become available for individuals of endangered species in captive breeding programs. There have been suggestions that this information be used to identify rare alleles, particularly those at the MHC, that can be subsequently selected for captive breeding programs. First, we summarize the current information on the MHC relevant to conservation genetics, so that such a possible breeding program is seen in a proper perspective. For example, very few specific alleles at the MHC have been identified as selectively advantageous, even though ther...
Characterisation of equine influenza isolates from the 1987 epizootic in India by nucleotide sequencing of the HA1 gene. Two A/Equi-2 (H3N8) isolates were obtained during the 1987 Indian equine influenza epizootic. The sequence of the Ludhiana/87 HA1 gene revealed that this isolate was very similar to recent European and North American isolates of equine influenza. In contrast, the Bhiwani/87 HA1 gene was nearly identical to the Miami/63 prototype H3 sequence. These results support the antigenic analysis previously carried out on these isolates using monoclonal antibodies. However, the finding that Bhiwani/87 is so similar to Miami/63, coupled with the finding that equine H3N8 influenza viruses have previously b...
Genetic and antigenic analysis of an equine influenza H 3 isolate from the 1989 epidemic. The haemagglutinin (HA) gene from the equine influenza H3N8 isolate Suffolk/89 has been cloned by reverse transcription and polymerase chain reaction amplification. The nucleotide sequence of the HA gene was determined from two independently cloned copies of the gene and was found to be most closely related to recent American isolates supporting the idea that most isolates of equine H3N8 are evolving as a single lineage. When the predicted amino acid sequence of the Suffolk/89 HA was examined, changes had taken place in at least four of the major antigenic sites, A, B, C, and D when compared t...
