Cloning of highly polymorphic microsatellites in the horse

Transmission ratio distortion detection by neutral genetic markers in the Pura Raza Española horse breed

Transmission Ratio Distortion (TRD) is a genetic phenomenon widely demonstrated in several livestock species, but barely in equine species. The TRD occurs when certain genotypes are over- or under-represented in the offspring of a particular mating and can be caused by a variety of factors during gamete formation or during embryonic development. For this study, 126 394 trios consisting of a stallion, mare, and offspring were genotyped using a panel of 17 neutral microsatellite markers recommended by the International Society for Animal Genetics for paternity tests and individual identification. The number of alleles available for each marker ranges from 13 to 18, been 268 the total number of alleles investigated. The TRDscan v.2.0 software was used with the biallelic procedure to identify regions with distorted segregation ratios. After completing the analysis, a total of 12 alleles (out of 11 microsatellites) were identified with decisive evidence for genotypic TRD; 3 and 9 with additive and heterosis patterns, respectively. In addition, 19 alleles (out of 10 microsatellites) were identified displaying allelic TRD. Among them, 14 and 5 were parent-unspecific and stallion-mare-specific TRD. Out of the TRD regions, 24 genes were identified and annotated, predominantly associated with cholesterol metabolism and homeostasis. These genes are often linked to non-specific symptoms like impaired fertility, stunted growth, and compromised overall health. The results suggest a significant impact on the inheritance of certain genetic traits in horses. Further analysis and validation are needed to better understand the TRD impact before the potential implementation in the horse breeding programme strategies.

Analysis of genetic diversity and structure of Mongolian horse using microsatellite markers

Mongolian horses are one of the oldest horse breeds, and are very important livestock in Mongolia as they are used in various fields such as transportation, food (milk, meat), and horse racing. In addition, research and preservation on pure Mongolian breeds are being promoted under the implementation of the new Genetics of Livestock Resources' act in Mongolia. However, despite the implementation of this act, genetic research on Mongolian horses using microsatellites (MS) has not progressed enough. Therefore, this study was conducted to analyze the genetic polymorphism of five breeds (Gobi shankh, Tes, Gal shar, Darkhad, and Undurshil) using 14 MS markers recommended by International Society for Animal Genetics (ISAG). The mean number of alleles (MNA) was 8.29, expected heterozygosity frequency (H_Exp) was 0.767, observed heterozygosity frequency (H_Obs) was 0.752, and polymorphism information content (PIC) was 0.729. The Nei's genetic distance analysis showed that the genetic distance between Gobi shankh and Darkhad horses was the farthest, and the other three breeds, Tes, Gal shar, and Undurshil were found to be close to each other. Similarly, the principal coordinate analysis (PCoA) and factorial correspondence analysis (FCA) showed that the Gobi shankh and Darkhad horses were genetically distinct from other breeds. On the other hand, it appears that Tes, Gal shar, and Undurshil horses, which are genetically similar, most likely interbred with each other. Therefore, it is expected that these results will help the conservation of genetic resources in Mongolia and the establishment of policies related to Mongolian horses.

Genetic Analysis and Status of Brown Bear Sub-Populations in Three National Parks of Greece Functioning as Strongholds for the Species’ Conservation

In order to optimize the appropriate conservation actions for the brown bear (Ursus arctos L.) population in Greece, we estimated the census (Nc) and effective (Ne) population size as well as the genetic status of brown bear sub-populations in three National Parks (NP): Prespa (MBPNP), Pindos (PINDNP), and Rhodopi (RMNP). The Prespa and Pindos sub-populations are located in western Greece and the Rhodopi population is located in eastern Greece. We extracted DNA from 472 hair samples and amplified through PCR 10 microsatellite loci. In total, 257 of 472 samples (54.5%) were genotyped for 6–10 microsatellite loci. Genetic analysis revealed that the Ne was 35, 118, and 61 individuals in MBPNP, PINDNP, and RMNP, respectively, while high levels of inbreeding were found in Prespa and Rhodopi but not in Pindos. Moreover, analysis of genetic structure showed that the Pindos population is genetically distinct, whereas Prespa and Rhodopi show mutual overlaps. Finally, we found a notable gene flow from Prespa to Rhodopi (10.19%) and from Rhodopi to Prespa (14.96%). Therefore, targeted actions for the conservation of the bears that live in the abovementioned areas must be undertaken, in order to ensure the species’ viability and to preserve the corridors that allow connectivity between the bear sub-populations in Greece.

Genetic Diversity and Structure of the Main Danubian Horse Paternal Genealogical Lineages Based on Microsatellite Genotyping

Simple Summary

The Danubian horse was created on the former Klementina stud farm near Pleven to satisfy the demands of the Bulgarian Army for light draft horses and to improve the working capacity of the local horse population. The privatization of the Klementina stud farm in the late 1990s and the lack of economic activity have led to a sharp reduction in the number of mares and stallions and their sale to private owners. At present, only six of the main paternal lines which participated in the creation of the Danubian horse breed are preserved: Zdravko, NONIUS XVII-30, Torpedo, Lider, Kalifa, and Hrabar. This is the first study on the genetic and population diversity of the Danubian horse paternal lines based on microsatellite markers (STRs). The results showed that the studied Danubian horse population was characterized by a high level of genetic diversity with a medium value of 0.84. The fixation index (F_ST) was 0.08 for all studied markers, which is indicative of the low genetic differentiation of the Danubian horse population. Our analysis also confirmed the low level of inbreeding and heterozygous deficiency among the animals selected from the six paternal lineages of the Danubian horse. The present research could be helpful for the development of breeding and conservation programs for the Danubian horse, as well as for making informed decisions on the management of paternal lines.

Abstract

The Danubian horse, together with the Pleven and the Eastern Bulgarian horse breeds, is one of the modern breeds in Bulgaria. The objective of this study was to compare the genetic structure and genetic diversity of six paternal genealogical lineages of the Danubian horse breed (Zdravko, NONIUS XVII-30, Torpedo, Lider, Kalifa, and Hrabar). In total, 166 individuals from the six genealogical lines were investigated, based on 15 STR markers (short tandem repeats, also known as microsatellites). In total, 184 alleles were found in the six populations, using 15 microsatellite loci. The mean number of alleles, the effective number of alleles, and the polymorphic information content (PIC) values per locus were 12.28, 9.48, and 0.73, respectively. In a comparison of the allelic diversity among sire lineages, the highest genetic diversity (Na) was observed in Lider and Kalifa (14.60 ± 0.21), while the lowest value of this parameter was observed in the Zdravko lineage 4.20 ± 0.35. The largest genetic diversity was found in loci HMS3 and HMS7, with 13 alleles, and the smallest polymorphism was noted for the locus ASB17, with 10 alleles. The level of observed heterozygosity was in the range of 0.65 ± 0.069 for the Zdravko lineage to 0.93 ± 0.01 for the Torpedo lineage. The expected heterozygosity level range was from 0.57 ± 0.048 to 0.91 ± 0.01 for all horse lineages. Structure analysis revealed three main gene pools in the study population. The first pool included the Zdravko lineage; the second had the NONIUS XVII-30, Torpedo, Lider, and Kalifa lineages; and the third defined the Hrabar lineage, which was significantly differentiated from the other genealogical lineages.

Genetic diversity and population structure of Mongolian regional horses with 14 Microsatellite markers

Objective

This study aimed to identify the genetic diversity and population structure of Mongolian horse populations according to the province of residence (Khentii, KTP; Uvs, USP; Omnogovi and Dundgovi, GOP; Khovsgol, KGP) using 14 microsatellite (MS) markers.

Methods

A total of 269 whole blood samples were obtained from the four populations (KTP, USP, GOP, KGP) geographically distinct provinces. Multiplex polymerase chain reaction (PCR) was conducted using 14 MS markers (AHT4, ASB2, ASB17, ASB23, CA425, HMS1, HMS2, HMS3, HMS6, HMS7, HTG4, HTG6, HTG7, and VHL20), as recommended by the International Society for Animal Genetics. Capillary electrophoresis was conducted using the amplified PCR products, alleles were determined. Alleles were used for statistical analysis of genetic variability, Nei’s DA genetic distance, principal coordinate analysis (PCoA), factorial corresponding analysis (FCA), and population structure.

Results

On average, the number of alleles, expected heterozygosity (H_Exp), observed heterozygosity (H_Obs), and polymorphic information content among all populations were 11.43, 0.772, 0.757, and 0.737, respectively. In the PCoA and FCA, GOP, and KGP were genetically distinct from other populations, and the KTP and USP showed a close relationship. The two clusters identified using Nei’s DA genetic distance analysis and population structure highlighted the presence of structurally clear genetic separation.

Conclusion

Overall, the results of this study suggest that genetic diversity between KTP and USP was low, and that between GOP and KGP was high. It is thought that these results will help in the effective preservation and improvement of Mongolian horses through genetic diversity analysis and phylogenetic relationships.

Evaluation of recent changes in genetic variability in Thoroughbred horses based on microsatellite markers parentage panel in Korea

Objective

In this study, we aimed to investigate the recent changes such as allele frequencies and total probability of exclusion (PE) in Thoroughbred horses in Korea using short tandem repeat (STR) parentage panels between 2006 and 2016.

Methods

The genotype was provided for 5,988 horse samples with 15 microsatellite markers (AHT4, AHT5, ASB2, ASB17, ASB23, CA425, HMS1, HMS2, HMS3, HMS6, HMS7, HTG4, HTG10, LEX3 and VHL20).

Results

In our study, the observed number of alleles per locus ranged from 3 (HMS1) to 9 (ASB17) in 2006 and 4 (HMS1) to 9 (ASB2) in 2016, with a mean value of 6.28 and 6.40, respectively. Of the 15 markers, HMS2, HTG4, and CA425 loci had relatively low polymorphism information content (<0.5000) in the Thoroughbred population. Mean levels of genetic variation in 2006 and 2016 were observed heterozygosity (H_O) = 0.708, and expected heterozygosity (H_E) = 0.685, as well as and H_O = 0.699 and H_E = 0.682, respectively. The PE was calculated for each group based on the allele frequencies of 14 or 15 STRs. The 2006 survey analyzed that PE was 0.9998, but it increased to 0.9999 in 2016 after the HMS2 marker was added in 2011. The current STR panel is still a powerful tool for parentage verification that contributes to the maintenance of integrity in the Thoroughbred population.

Conclusion

The current STR panel is still a powerful tool for parentage verification that contributes to the maintenance of integrity in the Thoroughbred horses. However, continuous monitoring genetic variability is necessary.

Assessment of genetic diversity using microsatellite markers to compare donkeys (Equus asinus) with horses (Equus caballus)

Objective

The study aimed to evaluate the diversity of donkey populations by comparing with the diversity of Thoroughbred and Jeju Halla horses; identified breeding backgrounds can contribute to management and conservation of donkeys in South Korea.

Methods

A total of 100 horse (50 Thoroughbreds and 50 Jeju Halla horses) and 79 donkeys samples were genotyped with 15 microsatellite markers (AHT4, AHT5, ASB2, ASB17, ASB23, CA425, HMS1, HMS2, HMS3, HMS6, HMS7, HTG4, HTG10, LEX3, and VHL20), to identify genetic diversity and relationships among horses and donkeys.

Results

The observed number of alleles per locus ranged from 1 (ASB17, HMS1) to 14 (AHT5), with a mean value of 4.87, 8.00, and 5.87 in Thoroughbreds, Jeju Halla horses, and donkeys, respectively. Of the 15 markers, AHT4, AHT5, ASB23, CA425, HMS2, HMS3, HTG4, HTG10, and LEX3 loci had relatively high polymorphism information content (PIC) values (PIC>0.5) in these three populations. Mean levels of genetic variation were H_E = 0.6721 and H_O = 0.6600 in Thoroughbreds, H_E = 0.7898 and H_O = 0.7100 in Jeju Halla horses, and H_E = 0.5635 and H_O = 0.4861 in donkeys. Of the 15 loci in donkeys, three loci had negative inbreeding coefficients (FIS), with a moderate mean FIS (0.138). The FIS estimate for the HTG4 marker was highest (0.531) and HMS6 marker was lowest (−0.001). The total probability of exclusion value of 15 microsatellite loci was 0.9996 in donkeys.

Conclusion

Genetic cluster analysis showed that the genetic relationship among 79 donkeys was generally consistent with pedigree records. Among the three breeds, donkeys and Thoroughbred horses formed clearly different groups, but the group of Jeju Halla horses overlapped with that of Thoroughbred horses, suggesting that the loci would be suitable for donkey parentage testing. Therefore, the results of this study are a valid tool for genetic study and conservation of donkeys.

Genetic Characterization of Native Donkey (Equus asinus) Populations of Turkey Using Microsatellite Markers

Simple Summary

This study was conducted to evaluate the genetic variability of Turkish native donkey (Equus asinus) populations, using polymorphism of 17 microsatellite markers. The results revealed a highly mixed genotype of all the examined donkeys, suggesting that two different group of breeds can be distinguished from each other on the basis of microsatellite markers.

Abstract

This study presents the first insights to the genetic diversity and structure of the Turkish donkey populations. The primary objectives were to detect the main structural features of Turkish donkeys by microsatellite markers. A panel of 17 microsatellite markers was applied for genotyping 314 donkeys from 16 locations of Turkey. One hundred and forty-two alleles were identified and the number of alleles per locus ranged from 4 to 12. The highest number of alleles was observed in AHT05 (12) and the lowest in ASB02 and HTG06 (4), while ASB17 was monomorphic. The mean H_O in the Turkish donkey was estimated to be 0.677, while mean H_E was 0.675. The polymorphic information content (PIC) was calculated for each locus and ranged from 0.36 (locus ASB02) to 0.98 (locus AHT05), which has the highest number of alleles per locus in the present study. The average PIC in our populations was 0.696. The average coefficient of gene differentiation (G_ST) over the 17 loci was 0.020 ± 0.037 (p < 0.01). The G_ST values for single loci ranged from −0.004 for LEX54 to 0.162 for COR082. Nei’s gene diversity index (H_t) for loci ranged from 0.445 (ASB02) to 0.890 (AHT05), with an average of 0.696. A Bayesian clustering method, the Structure software, was used for clustering algorithms of multi-locus genotypes to identify the population structure and the pattern of admixture within the populations. When the number of ancestral populations varied from K = 1 to 20, the largest change in the log of the likelihood function (ΔK) was when K = 2. The results for K = 2 indicate a clear separation between Clade I (KIR, CAT, KAR, MAR, SAN) and Clade II (MAL, MER, TOK, KAS, KUT, KON, ISP, ANT, MUG, AYD and KAH) populations.

Genetic Testing in the Horse

Genetic testing in horses began in the 1960s, when parentage testing using blood group markers became the standard. In the 1990s, parentage testing shifted from evaluating blood groups to DNA testing. The development of genetics and genomics in both human and veterinarian medicine, along with continued technological advances in the last 2 decades, has helped unravel the causal variants for many horse traits. Genetic testing is also now possible for a variety of phenotypic and disease traits and is used to assist in breeding and clinical management decisions. This article describes the genetic tests that are currently available for horses.

Long-term persistence of horse fecal DNA in the environment makes equids particularly good candidates for noninvasive sampling

Fecal DNA collected noninvasively can provide valuable information about genetic and ecological characteristics. This approach has rarely been used for equids, despite the need for conservation of endangered species and management of abundant feral populations. We examined factors affecting the efficacy of using equid fecal samples for conservation genetics. First, we evaluated two fecal collection methods (paper bag vs. ethanol). Then, we investigated how time since deposition and month of collection impacted microsatellite amplification success and genotyping errors. Between May and November 2014, we collected feral horse fecal samples of known age each month in a feral horse Herd Management Area in western Colorado and documented deterioration in the field with photographs. Samples collected and dried in paper bags had significantly higher amplification rates than those collected and stored in ethanol. There was little difference in the number of loci that amplified per sample between fresh fecal piles and those that had been exposed to the environment for up to 2 months (in samples collected in paper bags). After 2 months of exposure, amplification success declined. When comparing fresh (0–2 months) and old (3–6 months) fecal piles, samples from fresh piles had more matching genotypes across samples, better amplification success and less allelic dropout. Samples defecated during the summer and collected within 2 months of deposition had highest number of genotypes matching among samples, and lowest rates of amplification failure and allelic dropout. Due to the digestive system and amount of fecal material produced by equids, as well as their occurrence in arid ecosystems, we suggest that they are particularly good candidates for noninvasive sampling using fecal DNA.

Analysis of Genetic Diversity and Structure of Guanzhong Horse Using Microsatellite Markers

To determine the genetic diversity and validate the pedigree record of Chinese Guanzhong horse, 67 individuals were genotyped with eight microsatellite markers. In our study, the mean observed and expected heterozygosities were 0.51 and 0.66, respectively. The mean observed number of alleles for the Guanzhong horse was 3.88. Nonetheless, the total value of F_ST multiloci clearly indicates that about 0.5% of overall genetic variation is due to line founder differences, while differences among individuals are responsible for the remaining 99.5%. In addition, the polymorphic information content (PIC) result showed that five loci (HTG7, HMS7, HMS2, AHT4, and HMS6) were highly polymorphic (PIC > 0.5) and three loci (HMS3, HTG6, and COR071) were moderate polymorphic (PIC > 0.25). Genetic distances and cluster analysis showed that the genetic relationship among 67 Guanzhong horse was generally consistent with pedigree recorded. Our results not only evaluated the genetic diversity of Chinese Guanzhong horse, but also suggested that the eight microsatellite markers might be used as subservient markers for parentage verification and individual identification in the Guanzhong horse.

Genotyping horse epithelial cells from fecal matter by isolation of polymerase chain reaction products

Aim

To show that application of the polymerase chain reaction (PCR) method modified for amplification of a low-copy number DNA samples, ie, the isolation of PCR products (IPCRp), would represent improvement in obtaining genotypes from a fecal DNA compared with previously used genotyping methods.

Methods

The DNA from the horse fecal matter was extracted by modified Qiagen DNA Stool Mini Kit protocol. Following the extraction, the DNA genotypes from fecal samples were obtained by the most powerful PCR amplification method, the IPCRp. The IPCRp-based multiplex kit amplified biotin-labeled strands were captured on streptavidin-coated plates, where everything but the dye-labeled target sequence was washed, eliminating all the background noise, released, and run on a genotyping instrument in a single-strand configuration.

Results

The IPCRp-based multiplex kit (6 loci) revealed equine DNA full genotype profiles, ie, appearance of all six loci, when sampled from fresh feces in 87% of the samples and partial genotype profile (appearance of one to five loci) in 13% of the samples, for a total of 100% genotyping success rate.

Conclusion

These results indicate that the IPCRp amplification method, coupled with the Qiagen DNA Stool Mini Kit extraction can maximize the likelihood of obtaining horse DNA genotypes from fecal samples.

Morphological and genetic characterization of an emerging Azorean horse breed: the Terceira Pony

The Terceira Pony is a horse indigenous to Terceira Island in the Azores. These horses were very important during the colonization of the island. Due to their very balanced proportions and correct gaits, and with an average withers height of 1.28 m, the Terceira Pony is often confused with a miniature pure-bred Lusitano. This population was officially recognized as the fourth Portuguese equine breed by the national authorities in January, 2014. The aim of this study was to analyze the morphology and the genetic diversity by means of microsatellite markers of this emerging horse breed. The biometric data consisted of 28 body measurements and nine angles from 30 animals (11 sires, 19 dams). The Terceira Pony is now a recognized horse breed and is gaining in popularity amongst breeders and the younger riding classes. The information obtained from this study will be very useful for conservation and management purposes, including maximizing the breed’s genetic diversity, and solidifying the desirable phenotypic traits.

Microsatellite analysis of genetic variability in Waler horses from Australia

The Waler horse breed is an integral part of Australian history. The purposes of this study were to analyse the genetic variability in Waler horses from Australia and to investigate genetic relationships with other horse breeds. We examined the genetic diversity of 70 Waler horses sampled from seven breeding stations in Australia. Also we analysed the relationships of these horses with 11 other horse breeds. Analysis of the genetic structure was carried out using 15 microsatellite loci, genetic distances, AMOVA, factorial correspondence analysis and a Bayesian method. We found that the genetic diversity in the Waler was greater than the domestic horse mean and exceeded that of all endangered horse breeds. Our findings also revealed moderate population subdivision rather than inbreeding. All genetic similarity measures indicated that the Thoroughbred might be a key ancestor to the Waler. This study indicates that there is no immediate concern for loss of variation in Waler horses. Also, there clearly has been a strong input from the Thoroughbred into the Waler horse breed. However, the genetic evidence suggests that this input was not just direct but also came through other types of horses with a Thoroughbred cross background.

Genetic structure and differentiation of the Italian catria horse

Catria is 1 of the 22 native Italian horse breeds that now survive from a larger number. Thirty individuals, representative of the Catria horse, were analyzed for 11 microsatellites and compared with data of 10 breeds reared in Italy. Three different approaches, genetic distances, correspondence analysis, and clustering methods, were considered to study genetic relationships among Catria and the other horse populations. Genetic differentiation among breeds was highly significant (P < 0.01) for all loci. Average F(ST) values indicate that around 10% of the total genetic variation was explained by the between-breed differences and the 3 approaches utilized gave similar results. Italian native breeds are clearly separated from the other examined breeds. However, by the correspondence analysis, the Catria appears closer to Maremmano and Murgese. The results of Bayesian approaches give further information showing for Catria a common origin with Maremmano and Italian Heavy Draught. Genetic relationships among Catria and the other breeds are consistent with the breed's documented history. The data and information found here can be utilized in the organization of conservation programmes planned to reduce inbreeding and to minimize loss of genetic variability.

European domestic horses originated in two holocene refugia

The role of European wild horses in horse domestication is poorly understood. While the fossil record for wild horses in Europe prior to horse domestication is scarce, there have been suggestions that wild populations from various European regions might have contributed to the gene pool of domestic horses. To distinguish between regions where domestic populations are mainly descended from local wild stock and those where horses were largely imported, we investigated patterns of genetic diversity in 24 European horse breeds typed at 12 microsatellite loci. The distribution of high levels of genetic diversity in Europe coincides with the distribution of predominantly open landscapes prior to domestication, as suggested by simulation-based vegetation reconstructions, with breeds from Iberia and the Caspian Sea region having significantly higher genetic diversity than breeds from central Europe and the UK, which were largely forested at the time the first domestic horses appear there. Our results suggest that not only the Eastern steppes, but also the Iberian Peninsula provided refugia for wild horses in the Holocene, and that the genetic contribution of these wild populations to local domestic stock may have been considerable. In contrast, the consistently low levels of diversity in central Europe and the UK suggest that domestic horses in these regions largely derive from horses that were imported from the Eastern refugium, the Iberian refugium, or both.

Genetic diversity and population structure of three Indian horse breeds

The genetic relationships of three Indian horse breeds-Marwari, Spiti, and Kathiawari were studied by genotyping 96 individuals with 20 polymorphic microsatellite markers. A total of 157 alleles were detected across 20 polymorphic loci. The Marwari population showed the highest allelic diversity (A = 5.7 and Ar = 5.14), followed by Spiti (A = 4.9 and Ar = 4.74) and Kathiawari (A = 4.1 and Ar = 3.82). The gene diversity was highest in the Spiti population (He = 0.67), followed by Marwari (He = 0.66) and Kathiawari (He = 0.59). Within population inbreeding estimates (f) in Marwari, Spiti and Kathiawari breeds were 0.18, 0.08, and 0.07, respectively, suggesting high level of inbreeding in these breeds. Analysis of bottleneck revealed evidence of recent bottleneck in Spiti and Kathiawari populations. Pair-wise Fst analysis, AMOVA and assignment tests demonstrated high genetic differentiation and low gene flow between populations. The information about genetic diversity and population structure will be useful for the future development of effective breeding management in order to preserve these Indian horse breeds.

Genotyping in the Brazilian Criollo Horse Stud Book: resources and perspectives

The goal of this research was to evaluate the ability of the genotyping information available in the Brazilian Criollo Horse Stud Book to describe the genetic variability of the breed and the exclusion probability determined in comparative tests. Altogether, two softwares were used in the analyses of the available genotypes: Cervus 3.0.3 and Genepop 4.0. Eight microsatellite markers totaled 109 alleles, with an average of 13.6 +/- 0.6 alleles per locus. Large differences between expected and observed heterozygosity were ubiquitous (0.821 +/- 0.07 and 0.470 +/- 0.17, respectively). Although the estimated null allele frequency caused initial concern (0.284 +/- 0.199), it is likely that it was a reflection of the inbreeding coefficients found (0.432 +/- 0.184). All loci showed significant deviation from Hardy-Weinberg equilibrium, with heterozygote deficit (P < 0.0001) and genotypic linkage disequilibrium with at least one marker. The high polymorphic information content (0.798 +/- 0.088) could not warrant exclusion power for three loci (HMS7, HMS6 and HTG4) above 50% (0.491 +/- 0.158). However, combined exclusion probability reached 99.61%, a level close to ideal. The results demonstrate the excellent performance of the markers assessed in describing the genetic status of the breed and suggest the considerable ability to establish parentage.

Paternity assessment: application on estimation of breeding value in body-weight at first egg trait of egg-laying duck (Anas platyrhynchos)

Paternity index was analyzed using five microsatellite loci among Chinese egg-laying ducks (Anas platyrhynchos). Based on the paternity relationship that was identified by paternity index analysis, the estimated breeding value (EBV) was calculated using BLUP (best linear unbiased predictor) method. Body weight at first egg (BWF) is the only considered trait in this study. In total, 12 sires, 31 dams and 77 daughters were involved in the EBV calculation. The results demonstrated that five microsatellite loci's polymorphism information content (PIC) ranged from 0.795 in locus AY493338 to 0.957 in locus AY493264 with average 0.899; the parent-offspring relationships were built by these microsatellites' genotype, 12 families of half sibling and 2 families of full sibling were involved, and the relationship error is smaller than 10(-7). The EBV results suggest that the average EBV was significantly higher in females (average EBV is 10.234 and 0.1045 for mother and daughter, respectively) than males (average EBV is just -26.44). The EBV results on BWF were in good agreement with the principle of GH (growth hormone) expression in poultry. These results show that paternity analyses of Chinese egg-laying ducks were basically resolved using the five microsatellite loci selected. The paternity relationships can apply in Chinese egg-laying duck breeding to quicken the improvement of genetic progress.

Genetic analysis, breed assignment and conservation priorities of three native Danish horse breeds

A genetic analysis was performed on three indigenous Danish horse breeds using 12 microsatellite markers from a standard kit for parental testing. These three breeds are all considered endangered based on their small population sizes. Genetic variation in these three breeds was comparable to other horse breeds in Europe, and they do not seem to be at immediate danger of extinction caused by genetic deterioration. The Knabstrupper breed had more genetic variation, as measured by expected heterozygosity and allelic richness, than the other two breeds (Frederiksborg and Jutland). F(ST) statistics and population assignments confirmed population differentiation into three distinct breeds. The Frederiksborg and Knabstrupper breeds were closer to each other than to the Jutland breed. When establishing conservation priorities for the breeds, the priorities will depend on the conservation goals. Different methods for establishing conservation priorities are also discussed.

A Case of Multiple Assignments (Paternity/Maternity) in an Equine-Out Breeding System

Recently, the use of DNA markers has provided a more accurate method of identifying individuals and verifying parentage. In this report, we describe foal assignment in a farm bred jumping horses (Silla argentino). Ten mares were freely served by two stallions, resulting in nine foals. Weaning occurred without registration of the mare of each offspring, resulting in a failure to identify either the mare or the sire of each foal. Animals were typed using 12 microsatellite systems and four biochemical polymorphisms in order to determine the paternity/maternity of each foal. We used the CERVUS program to evaluate the parentage of each offspring. It was possible to determine maternity in eight cases, and paternity in all of them. We concluded that this set of codominant markers analyzed following a likelihood-based approach included in the CERVUS package, are useful tools to solve parentage assignments in domestic horses.

Genetic structure and phylogenetic relationships of the Polish Heavy horse

In this study a wide range of genetic markers (12 microsatellites, 7 blood-group loci, 10 blood-protein loci) and mitochondrial DNA (mtDNA) were used to assess genetic diversity in Polish Heavy horses. Three random samples were sequenced for 421 bp of the mitochondrial D-loop region, but no clear phylogenetic patterns were seen in mtDNA variation. Both heterozygosity and diversity levels are fairly high in Polish Heavy horses. In phylogenetic analysis the draught horses form a distinct cluster that pairs with the true pony breeds. Within this 'cold-blooded' group, the Polish Heavy Horse clusters most closely with the Posavina breed from Croatia and the Breton breed from France. From the standpoint of genetic conservation, the Polish Heavy Horse does not appear to be in jeopardy.

Genetic diversity and relationships of Portuguese and other horse breeds based on protein and microsatellite loci variation

There are three native Portuguese horse breeds: Lusitano, Sorraia and Garrano. This study compares diversity patterns of 17 protein and 12 microsatellite markers in these three as well as 30 other breeds to infer relationships among the breeds and to compare levels of polymorphism of these breeds for use in conservation efforts. The Garrano and the Lusitano showed a high level of genetic diversity, similar to that observed for most of the other analysed breeds, while the Sorraia and Friesian breeds showed low levels of variation for both genetic marker types. The combined protein and microsatellite data produced a tree that fit historical records well and with greater confidence levels than those for either data set alone. The combined genetic diversity and relationship information provides important baseline data for future breed conservation efforts, especially for a critically endangered breed such as the Sorraia.