An investigation of seven enzymes as possible genetic markers in horse leucocytes

In this paper we describe seven enzymes, NP, GOT_M, PGM₂, αFUC, PEP A, ADA and MPI which are found in the white cells of horses, including 39 British crossbred ponies and 16 crossbred horses, 30 Mongolian ponies and 10 Icelandic ponies. Two of these enzymes - αFUC and MPI - were polymorphic in all the populations of horses studied and could prove useful as additional markers in the paternity testing of horses. PEP A and GOT_M were also polymorphic in two of the populations studied and could be used as further markers in these populations.     

Equine lymphocyte antigens in four major Belgian horse populations. Contribution to serology and antigen distribution

158 Belgian Saddlebreds, 130 Belgian Trotters, 108 Belgian Draft horses and 92 Shetland ponies have been typed for serologically defined antigens at the ELA and ELY systems. Gene frequencies were estimated in each breed for the internationally established ELA, ELY-1 and ELY-2 alleles as well as for locally assigned additional ELA markers and for subtypes of ELA-W3, W9 and W11. The distribution of ELA alleles was in agreement with the expected Hardy-Weinberg equilibrium for the 4 horse breeds described here. Differences in gene frequencies between these main Belgian horse populations were observed.     

Equine lymphocyte antigens in four major Belgian horse populations. Contribution to serology and antigen distribution

158 Belgian Saddlebreds, 130 Belgian Trotters, 108 Belgian Draft horses and 92 Shetland ponies have been typed for serologically defined antigens at the ELA and ELY systems. Gene frequencies were estimated in each breed for the internationally established ELA, ELY-1 and ELY-2 alleles as well as for locally assigned additional ELA markers and for subtypes of ELA-W3, W9 and W11. The distribution of ELA alleles was in agreement with the expected Hardy-Weinberg equilibrium for the 4 horse breeds described here. Differences in gene frequencies between these main Belgian horse populations were observed.     

The same ELA class II risk factors confer equine insect bite hypersensitivity in two distinct populations

Insect bite hypersensitivity (IBH) is a chronic allergic dermatitis common in horses. Affected horses mainly react against antigens present in the saliva from the biting midges, Culicoides ssp, and occasionally black flies, Simulium ssp. Because of this insect dependency, the disease is clearly seasonal and prevalence varies between geographical locations. For two distinct horse breeds, we genotyped four microsatellite markers positioned within the MHC class II region and sequenced the highly polymorphic exons two from DRA and DRB3, respectively. Initially, 94 IBH-affected and 93 unaffected Swedish born Icelandic horses were tested for genetic association. These horses had previously been genotyped on the Illumina Equine SNP50 BeadChip, which made it possible to ensure that our study did not suffer from the effects of stratification. The second population consisted of 106 unaffected and 80 IBH-affected Exmoor ponies. We show that variants in the MHC class II region are associated with disease susceptibility (p (raw)?=?2.34?×?10(-5)), with the same allele (COR112:274) associated in two separate populations. In addition, we combined microsatellite and sequencing data in order to investigate the pattern of homozygosity and show that homozygosity across the entire MHC class II region is associated with a higher risk of developing IBH (p?=?0.0013). To our knowledge this is the first time in any atopic dermatitis suffering species, including man, where the same risk allele has been identified in two distinct populations.     

A Cross-Sectional Epidemiological Study of Prevalence and Severity of Bit-Induced Oral Trauma in Polo Ponies and Race Horses

Bit and bridle accessories improperly fitted in ridden horses can cause oral trauma such as bone spurs, commissure ulceration, and tongue lacerations. This study was used to identify, grade, and compare the types of oral traumas commonly found within polo ponies and race horses. Injuries were assessed visually and by palpation on the tongue, lips’ commissures, and interdental space. A total of 50 polo ponies and 50 race horses were sampled in the South of England. A Poisson model was successfully fitted to the data (p < .001), and the variables of discipline (p < .001), injury type (p < .001), and age (p < .001) were significant. Race horses with snaffle bits were predisposed to significantly higher severities and prevalence of oral trauma than were polo ponies in gag bits. Only polo ponies were observed with tongue trauma. Race horses had higher severities of injuries in the commissures and bone spurs. Positive correlations were found between age and/or time in sport and induced biting injuries. Polo ponies had been playing longer before the occurrence of injuries.     

Eight polymorphic blood protein systems in Arab horses from Turkey]

Analysis of the blood protein system was used to study the genetic composition of Arabian horses. Biochemical markers of eight polymorphic loci (Tf, Al, Es, AlB, Gc, Hb, PGD, and PGM) were electrophoretically identified in blood samples. A total of 43 phenotypes were identified for these polymorphic systems. The Tf, Hb, and Es loci appeared to be more polymorphic than the other loci studied. Statistically significant differences between the observed and expected genotypic frequencies were found for the PGD and PGM loci (P < 0.05 and P < 0.01, respectively). Individual allele frequencies, observed and expected phenotype frequencies, and the average heterozygosity were estimated for each polymorphic locus.     

Characteristics of equine summer eczema with emphasis on differences between Finnhorses and Icelandic horses in a 11-year study

Summer eczema, allergic dermatitis of the horse, was studied on 275 affected horses in Finland in 1997–2007. Features of the horses, clinical signs of the disease and owners' opinions of aggravating factors were recorded. Differences, especially, between two of the native Scandinavian horse breeds, the Finnhorse and the Icelandic horse, were evaluated. The study was based on clinical examination and information from the owners. Of the horses, 50% were Finnhorses, 26% Icelandic horses and 24% consisted of different breeds of ponies and other horses. Of the Finnhorses, 76% had summer eczema by the age of 5 years, but in the Icelandic horses born in Finland the average age at onset was 7 years. The vast majority of the horses, 75%, had moderate clinical signs, while 16% showed severe and 9% mild. The severity of clinical signs did not depend on the duration of the disease nor was it related to the age at onset. The only linkage to severity was the breed of the horse or import from Iceland; New Forest ponies and imported Icelandic horses showed severe clinical signs significantly more often than Finnhorses. Of the owners, 38% regarded insects as the only aggravating factor, 24% mentioned several simultaneous factors, including grass fodder and sunlight, while 22% could not specify any. In Finland, a typical horse breed suffering from summer eczema is the Finnhorse and the characteristics of the disease are mainly uniform with the other breeds affected. Equine summer eczema seems to be aggravated by various combinations of environmental factors.     

Confirmation of the potential usefulness of two human beta globin pseudogene markers to estimate gene flows to and from sub-Saharan Africans

Two polymorphic sites, -107 and -100 with respect to the "cap" site of the human beta globin pseudogene, recently discovered in our laboratory, turned out to have an ethnically complementary distribution. The first site is polymorphic in Europeans, North Africans, Indians (Hindu), and Oriental Asians, and monomorphic in sub-Saharan Africans. Conversely, the second site is polymorphic in sub-Saharan African populations and monomorphic in the aforementioned populations. Here we report the gene frequencies of these two polymorphic sites in nine additional populations (Egyptians, Spaniards, Japanese, Chinese, Filipinos, Vietnamese, Africans from Togo and from Benin, and Pygmies), confirming their ethnospecificity and, through the analysis of these two markers in Oromo and Amhara of Ethiopia (two mixed populations), their usefulness in genetic admixture studies. Moreover, we studied another marker polymorphic in sub-Saharan African populations only, a TaqI restriction fragment length polymorphism located in the same region as the present markers, demonstrating the absence of linkage disequilibrium between it and the -100 site, so that we can exclude that the information they provide is redundant.     

云南普通马矮型马蛋白多态性及其品种分化关系

本文运用蛋白电泳技术对来自云南省文山州马关县和麻栗坡县的２１匹普通马和１４匹矮型马进行了分析。共分析遗传座位４４个,其中有１０个座位检测到多态性。根据分子钟假说和相应的公式,推算两者的分歧时间约为１８．５万年。     

Characterisation of IgG(T) serum antibody responses to two larval antigen complexes in horses naturally- or experimentally-infected with cyathostomins

Cyathostomins are the most common parasitic nematodes of horses. Larval stages, which inhabit the intestinal wall, are particularly pathogenic and can cause severe colitis and colic. Despite their clinical importance, diagnostic techniques for the prepatent stages do not exist. A method that could estimate mucosal infection intensity would have a major impact on the control and diagnosis of cyathostominosis. Here, serum IgG(T) responses to two larval antigen complexes of 25 and 20 kDa were quantified in horses with experimental infections, natural infections and in horses that presented with clinical larval cyathostominosis. In experimentally-infected animals, anti-25 kDa complex IgG(T) levels correlated positively with field exposure and with early third stage larval (r(s)=0.74, P=0.015) and total mucosal parasite (r(s)=0.78, P=0.010) burdens. In naturally exposed horses whose parasite burdens were quantified upon post-mortem examination, antigen-specific IgG(T) responses were significantly higher in infected than in uninfected horses (P=0.0001 and 0.002, for anti-25 and anti-20 kDa responses, respectively). In these animals, anti-25 kDa IgG(T) levels correlated positively with mucosal and lumenal burdens (P<0.05). IgG(T) responses to the 20 kDa antigen complex correlated positively with lumenal burdens (P=0.0043). In cases of larval cyathostominosis, antigen-specific IgG(T) levels were significantly higher than in uninfected ponies (P=0.002 and 0.0035, for anti-25 and anti-20 kDa responses, respectively). These results provide evidence that these two complexes contain antigens with potential as markers for prepatent cyathostomin infection.     

Effect of exercise on apparent total tract digestibility of nutrients and faecal recovery of ADL and TiO2 in ponies

Exercise and physical training are known to affect gastrointestinal function and digestibility in horses and can lead to inaccurate estimates of nutrient and energy digestibility when markers are used. The effect of exercise on apparent nutrient digestibility and faecal recoveries of ADL and TiO₂ was studied in six Welsh pony geldings subjected to either a low- (LI) or high-intensity (HI) exercise regime according to a cross-over design. Ponies performing LI exercise were walked once per day for 45 min in a horse walker (5 km/h) for 47 consecutive days. Ponies submitted to HI exercise were gradually trained for the same 47 days according a standardized protocol. Throughout the experiment, the ponies received a fixed level of feed and the daily rations consisted of 4.7 kg DM of grass hay and 0.95 kg DM of concentrate. The diet was supplemented with minerals, vitamins and TiO₂ (3.0 g Ti/day). Total tract digestibility of DM, organic matter (OM), CP, crude fat, NDF, ADF, starch, sugar and energy was determined with the total faeces collection (TFC) method. In addition, DM and OM digestibility was estimated using internal ADL and the externally supplemented Ti as markers. Urine was collected on the final 2 days of each experimental period. Exercise did not affect apparent digestibility of CP, crude fat, starch and sugar. Digestibility of DM (DMD), OM (OMD), ADF and NDF tended to be lower and DE was decreased when ponies received the HI exercise regime. For all treatments combined, mean faecal recoveries of ADL and Ti were 87.8±1.7% and 99.3±1.7%, respectively. Ti was not detected in the urine, indicating that intestinal integrity was maintained with exercise. Dry matter digestibility estimated with the TFC, ADL and Ti for ponies subjected to LI exercise were 66.3%, 60.3% and 64.8%, respectively, while DMD for HI ponies were 64.2%, 60.3% and 65.2%, respectively. In conclusion, physical exercise has an influence on the GE digestibility of the feed in ponies provided with equivalent levels of feed intake. In addition, the two markers used for estimating apparent DMD and OMD indicate that externally supplemented Ti is a suitable marker to determine digestibility of nutrients in horses performing exercise unlike dietary ADL.     

Characterization of dinucleotide microsatellite loci in the living fossil tadpole shrimp Triops cancriformis (Crustacea Branchiopoda Notostrace)

Five dinucleotide markers were obtained from a microsatellite genomic library of the tadpole shrimp Triops cancriformis. The number of alleles at each locus was low (maximum three alleles) but all loci were polymorphic. The presence of null alleles could not be disregarded. Heterozygosity levels were indicative of selfing in the studied populations whose real sexuality will be further tested using these markers.     

Linkage of the equine serum esterase (Es) and mitochondrial glutamate oxaloacetate transaminase (GOTM) loci. A horse-mouse homology

Three previously described electrophoretic phenotypes of mitochondrial glutamate oxaloacetate transaminase (GOTM) in horse leukocytes are shown to be controlled by two codominant alleles at a single autosomal locus. The GOTM locus is linked to the serum esterase locus (Es), as no recombination between these loci was observed among 16 informative offspring in one sire family. The results assign GOTM to equine linkage group (LG) II. The hypothesis that a part of LG II (e-Es) shares homologies with mouse chromosome 8 is thus confirmed, as the murine homologue of GOTM is located within the cluster of esterase loci on chromosome 8. The assumed homology also involves rabbit LG VI, rat LG V, and human chromosome 16. The observation is a striking example of the conservation of linkage relationships between mammalian species.     

Hemotypes and genetic structure of Camargue horses

The nature and distribution of hemotypes constituted by electrophoretic phenotypes in six loci, in a group of 183 Camargue horses, have been compared with those of five breeds of horses and ponies. The genetic similarities have been observed mainly with New Forest and Haflinger ponies, less with Barbs and Thoroughbreds, and the least with Arab horses.     

Social relations in a mixed group of mules, ponies and donkeys reflect differences in equid type

Donkeys and mules are frequently kept as companion animals for horses and ponies, with these different equids often being considered a homogenous group. However, the extent to which domestic equids form inter-specific bonds and display similar social behaviour when living in a mixed herd has not previously been studied. Here we compare the social organization of these three (sub)species when housed together, providing the first systematic analysis of how genetic hybridization is expressed in the social behaviour of mules. A group of 16 mules, donkeys and ponies was observed for 70h and preferred associates, dominance rank and the linearity of the group's hierarchy was determined. The different equids formed distinct affiliative groups that were ordered in a linear hierarchy with ponies as the most dominant, mules in the middle ranks and donkeys in the lowest ranks. Within each equid subgroup, the strength of the hierarchy also varied. Thus in the present study, the three (sub)species displayed different social organization and levels of dominance and preferred to associate with animals of the same equid type, given the opportunity. These results suggest that different domestic equid (sub)species display variations in social behaviour that are likely to have a strong genetic basis.     

Evaluation of Genetic Diversity,Population Structure,and Relationship Between Legendary Vechur Cattle and Crossbred Cattle of Kerala State,India

The legendary Vechur cattle of Kerala, described as a very short breed, and the crossbred (CB) Sunandini cattle population exhibited great phenotypic variation; hence, the present study attempted to analyze the genetic diversity existing between them. A set of 14 polymorphic microsatellites were chosen from FAO-ISAG panel and amplified from genomic DNA isolated from blood samples of 30 Vechur and 64 unrelated crossbred cattle, using fluorescent labeled primers. Both populations revealed high genetic diversity as evidenced from high observed number of alleles, Polymorphic Information Content and expected heterozygosity. Observed heterozygosity was lesser (0.699) than expected (0.752) in Vechur population which was further supported by positive F_IS value of 0.1149, indicating slight level of inbreeding in Vechur population. Overall, F_ST value was 0.065, which means genetic differentiation between crossbred and Vechur population was 6.5%, indicating that the crossbred cattle must have differentiated into a definite population that is different from the indigenous Vechur cows. Structure analysis indicated that the two populations showed distinct differences, with two underlying clusters. The present study supports the separation between Taurine and Zebu cattle and throws light onto the genetic diversity and relationship between native Vechur and crossbred cattle populations in Kerala state.     

RFLP and RAPD mapping in flax (Linum usitatissimum)

A map of flax (Linum usitatissimum) using restriction fragment length polymorphisms (RFLPs) and random amplified polymorphic DNAs (RAPDs), and comprising 15 linkage groups containing 94 markers, has been developed covering about 1000 cM. The mapping populations were the F₂ populations from two crosses between diverse cultivars. From one cross, CI1303 and Stormont Cirrus, 20 RFLP and 520 RAPD markers were analyzed. Thirteen RFLP and 80 RAPD markers were on the 15 linkage groups, in addition to one sequence-tagged site (STS). Seven polymorphic RAPD markers were found to have unusual segregation patterns. RAPDs were expressed as dominant markers, but for these markers a prevalence of the progeny lacked a band rather than the expected one-fourth ratio. However, these exceptions may be related to the instability of the genome of Stormont Cirrus in which stable and heritable genomic changes can be induced by environmental factors. The current map could be used for the identification of markers linked to loci controlling the ability to generate heritable changes in response to environmental growth conditions, and to develop anchor loci with STSs for a more general application. Received: 20 March 1999 / Accepted: 16 December 1999     

Assessment of Genetic Relatedness of Crossbred Chicken Populations Using Microsatellite Markers

To measure genetic relatedness between populations, for breeding purposes, we analyzed 170 birds from six crossbred populations of three pure lines of White Leghorn chickens, using 14 microsatellite markers. All the microsatellites were polymorphic, with 2–6 alleles. The mean number of alleles per locus was 3.21. The effective number of alleles varied from 1.14 to 3.94. The observed heterozygosity varied from 0.133 to 1.00, with a mean of 0.748. The F _IS values were mostly negative, with an average of ?0.345. The mean F _ST value was 0.056. The Nm values ranged from 1.91 to 42.17. The highest genetic identity was observed between IWI × IWK and IWK × IWI. The relation between any two groups of crosses was more than 85%. The results suggest that the crossbred populations were very closely related.     

Study of Eight Blood Protein Polymorphic Systems in Arabian Horses from Turkey

Analysis of the blood protein system was used to study the genetic composition of Arabian horses. Biochemical markers of eight polymorphic loci (Tf, Al, As, AlB, Gc, Hb, PGD, and PGM) were electrophoretically identified in blood samples. A total of 43 phenotypes were identified for these polymorphic systems. The Tf, Hb, and Esloci appeared to be more polymorphic than the other loci studied. Statistically significant differences between the observed and expected genotypic frequencies were found for the PGDandPGMloci (P< 0.05 and P< 0.01, respectively). Individual allele frequencies, observed and expected phenotype frequencies, and the average heterozygosity were estimated for each polymorphic locus.     

Isolation and characterization of 16 novel microsatellite loci in two inbred strains of the Chinese hamster (Cricetulus griseus)

The Shanyi inbred A and E strains of the Chinese hamster are widely used in biomedical research, but detailed genetic characterization has been lacking. We developed microsatellite markers that could be used for genetic diversity analysis and linkage map construction. We isolated and characterized 16 novel microsatellite loci from a microsatellite-enriched genomic DNA library. These loci were genotyped in 48 animals from the two strains, and the polymorphic information content was determined. In the Shanyi A and E populations, 14 and 15 loci were found to be polymorphic, respectively, with polymorphic information content ranging from 0.1393 to 0.8082 and from 0.1109 to 0.7397, respectively. A total of 115 alleles were found for the 16 microsatellite loci in the two populations; the mean observed heterozygosity (H(O)) was 0.5191 and 0.4333 for the A and E populations, respectively, indicating marked genetic variation within the two populations. Correspondingly, the F(ST) values ranged from 0.002 to 0.9253, with an overall mean of 0.1935, indicating significant genetic difference between the two strains. The population differentiation levels were substantiated by Nei's genetic distance and full Bayesian analyses computed with STRUCTURE. Despite the genetic diversity and differentiation within and between the two inbred populations, the 48 individuals were correctly allocated into their original populations with high statistical confidence based on these 16 microsatellite loci. These novel microsatellite loci should be useful genetic markers for these two Chinese hamster inbred strains.