Genetic analysis of Taishu horses on and off Tsushima Island: Implications for conservation.
Abstract: Taishu horses are a native Japanese breed, of which only 41 individuals remained on Tsushima Island in 2018. Their genetic diversity is considered lower than that of other Japanese native horse breeds; thus, it needs to be investigated for sustainable conservation of this breed. Historical records revealed that several Taishu individuals were released areas off-Tsushima Island in mid-1980s. At present, Taishu horses living outside of Tsushima Island, hereafter referred to as Non-Tsushima Taishus (NTTs), are tagged. However, the genetic structure of the NTT individuals remains unclear, and such individuals are not included in the current mating plans for Taishu horses. Herein, we examined the genetic structure of 18 NTT individuals by comparing their genomic (SNP) information with that of individuals on Tsushima Island (TT), four other native Japanese breeds, and one Anglo-Arabian breed by using ddRAD-seq. We found that all individuals related to the Taishu can be grouped in one cluster, which was separated from other horse breeds. Patterns of specific and shared SNPs in NTT individuals closely resembled those of TT individuals, suggesting very minor genetic differences. Meanwhile, the heterozygosity of NTT individuals was slightly higher than that of TT individuals, and many NTT individuals were of fertile age, suggesting that the pedigree of NTT individuals would be useful in breed conservation plans for Taishu horses. Based on their genomic information, we also reconstructed the pedigree structures of four NTT individuals with no family information. The inclusion of NTT individuals in future mating plans on Tsushima Island may be an effective and feasible method for conserving the Taishu horse breed in Japan.
Publication Date: 2019-07-03 PubMed ID: 31285691PubMed Central: PMC6606448DOI: 10.1294/jes.30.33Google Scholar: Lookup
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- Journal Article
Summary
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The research explores the genetic diversity of the endangered Taishu horse breed native to Japan, particularly the ones living off Tsushima Island. The study suggests that including these horses in the future breeding plans might be a feasible strategy for conserving this specific breed.
Study Overview
- The researchers focused on the Taishu breed of horses, that is native to Japan and currently in danger of extinction. Their 2018 count registered only 41 individuals left on Tsushima Island.
- Historical records suggest that some of these horses were moved to areas outside Tsushima Island in the mid-1980s. These horses, which the study refers to as Non-Tsushima Taishus (NTTs), were tagged but their genetic structure wasn’t fully studied. The study undertaken by the researchers aims at filling this knowledge gap.
Research Methodology
- The scientists compared the genomic structure (SNP or single nucleotide polymorphisms) information of 18 NTT individuals to that of the Taishu horses on Tsushima Island, sampled alongside four other native Japanese breeds and an Anglo-Arabian breed. The methodology they employed was called ddRAD-seq, which is a modern genomics technique.
- The research also aimed at reconstructing the pedigree of four NTT individuals which previously had no family information available.
Results
- All Taishu horses, irrespective of their current location, formed a single cluster genetically, which was distinct from other horse breeds. This suggests a strong genetic commonality within the breed.
- The breed’s genetic structure showed very minor genetic differences between horses on Tsushima Island and NTTs.
- Despite the small genetic differences, the study found the heterozygosity (genetic diversity) of NTT individuals to be slightly higher than that of the ones on Tsushima Island. Many NTT horses were of a fertile age, displaying potential to be included in breeding plans.
- The NTT horses could provide a valuable contribution to the conservation of the breed because of their higher genetic diversity and reproductive age. The study concludes that including NTT individuals in future mating plans might be a key strategy in saving the Taishu horse breed.
Cite This Article
APA
Tezuka A, Takasu M, Tozaki T, Nagano AJ.
(2019).
Genetic analysis of Taishu horses on and off Tsushima Island: Implications for conservation.
J Equine Sci, 30(2), 33-40.
https://doi.org/10.1294/jes.30.33 Publication
Researcher Affiliations
- Faculty of Agriculture, Ryukoku University, Shiga 520-2194, Japan.
- Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan.
- Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan.
- Genetic Analysis Department, Laboratory of Racing Chemistry, Tochigi 320-0851, Japan.
- Faculty of Agriculture, Ryukoku University, Shiga 520-2194, Japan.
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This article includes 10 references
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Citations
This article has been cited 1 times.- Yoshihara T, Kikuchi M, Akiba Y, Horiguchi M, Takasu M, Tozaki T. Genetic diversity analysis and parentage verification of Taishu horses using 31 microsatellites. J Equine Sci 2022 Dec;33(4):63-69.
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