Genetics of Equine Reproductive Diseases

Raudsepp, Terje

doi:10.1016/j.cveq.2020.03.013

Cited by 10 publications

(11 citation statements)

References 69 publications

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“…It is still unclear how cryptorchidism can be prevented [36]. Moreover, recent studies by Murase et al [37] revealed that, sometimes, the diagnosis can be challenging.…”

Section: Discussionmentioning

confidence: 99%

The G-Protein-Coupled Membrane Estrogen Receptor Is Present in Horse Cryptorchid Testes and Mediates Downstream Pathways

Witkowski

Pardyak

Pawlicki

et al. 2021

IJMS

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Cryptorchidism in horses is a commonly occurring malformation. The molecular basis of this pathology is not fully known. In addition, the origins of high intratesticular estrogen levels in horses remain obscure. In order to investigate the role of the G-protein-coupled membrane estrogen receptor (GPER) and establish histological and biochemical cryptorchid testis status, healthy and cryptorchid horse testes were subjected to scanning electron microscopy analysis, histochemical staining for total protein (with naphthol blue black; NBB), acid content (with toluidine blue O; TBO), and polysaccharide content (with periodic acid–Schiff; PAS). The expression of GPER was analyzed by immunohistochemistry and Western blot. GPER-mediated intracellular cAMP and calcium (Ca2+) signaling were measured immunoenzymatically or colorimetrically. Our data revealed changes in the distribution of polysaccharide content but not the protein and acid content in the cryptorchid testis. Polysaccharides seemed to be partially translocated from the interstitial compartment to the seminiferous tubule compartment. Moreover, the markedly decreased expression of GPER and GPER downstream molecules, cAMP and Ca2+, suggests their potential role in testis pathology. Increased estrogen levels in cryptorchid conditions may be linked to disturbed GPER signaling. We postulate that GPER is a prominent key player in testis development and function and may be used as a new biomarker of horse testis in health and disease.

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“…It is still unclear how cryptorchidism can be prevented [36]. Moreover, recent studies by Murase et al [37] revealed that, sometimes, the diagnosis can be challenging.…”

Section: Discussionmentioning

confidence: 99%

The G-Protein-Coupled Membrane Estrogen Receptor Is Present in Horse Cryptorchid Testes and Mediates Downstream Pathways

Witkowski

Pardyak

Pawlicki

et al. 2021

IJMS

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“…64,XY DSDs. Many cases of male-to-female sex reversal or XY DSDs have been described in horses and after X-monosomy, they are the most common equine chromosome abnormalities (reviewed by [ 4 , 5 , 10 , 11 , 12 , 13 , 14 , 133 , 134 ]). It has been estimated that approximately 12% to 30% of all cytogenetically abnormal cases are XY DSDs [ 28 , 44 , 135 ] ( Table 1 ).…”

Section: Chromosome Aberrationsmentioning

confidence: 99%

“…This group of XY DSDs encompasses female-like horses showing various degrees of masculinization and virilization, as well as stallion-like behavior. These horses usually have abnormally developed genital tract, the gonads can range from ovotestes to testicular feminization, and the cases are described as male pseudohermaphrodites, intersex or ambiguous sex [ 28 , 44 , 133 , 134 , 136 , 137 , 145 , 146 , 147 , 148 , 149 ].…”

Section: Chromosome Aberrationsmentioning

confidence: 99%

“…Over the years, tens of XX DSD cases have been described [ 133 , 139 , 154 , 155 , 156 , 157 , 158 , 159 , 160 ], including 41 unpublished cases from TAMUMCL ( Table 1 ). While clinical details of individual cases may vary, they are typically reported as intersex, hermaphrodite or ambiguous sex because of difficulties to decide about the gonadal and/or phenotypic sex of the horse (reviewed by [ 134 ]). Molecular causes of equine XX DSD are unknown.…”

Section: Chromosome Aberrationsmentioning

confidence: 99%

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Horse Clinical Cytogenetics: Recurrent Themes and Novel Findings

Bugno‐Poniewierska

Raudsepp

2021

Animals

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Clinical cytogenetic studies in horses have been ongoing for over half a century and clearly demonstrate that chromosomal disorders are among the most common non-infectious causes of decreased fertility, infertility, and congenital defects. Large-scale cytogenetic surveys show that almost 30% of horses with reproductive or developmental problems have chromosome aberrations, whereas abnormal karyotypes are found in only 2–5% of the general population. Among the many chromosome abnormalities reported in the horse, most are unique or rare. However, all surveys agree that there are two recurrent conditions: X-monosomy and SRY-negative XY male-to-female sex reversal, making up approximately 35% and 11% of all chromosome abnormalities, respectively. The two are signature conditions for the horse and rare or absent in other domestic species. The progress in equine genomics and the development of molecular tools, have qualitatively improved clinical cytogenetics today, allowing for refined characterization of aberrations and understanding the underlying molecular mechanisms. While cutting-edge genomics tools promise further improvements in chromosome analysis, they will not entirely replace traditional cytogenetics, which still is the most straightforward, cost-effective, and fastest approach for the initial evaluation of potential breeding animals and horses with reproductive or developmental disorders.

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“…Therefore, efforts are made to carefully evaluate prospective breeding stallions for breeding soundness, which typically involves detailed physical examination and semen analysis (Blanchard & Varner 1997). The breeding soundness evaluation, however, rarely involves genetic tests, mainly because of limited knowledge about the genetic component of stallion fertility (Raudsepp 2020). Today, the only routinely conducted genetic test for stallion evaluation is karyotyping (Raudsepp & Chowdhary 2016;Raudsepp 2020), but the findings of clinical cytogenetics indicate that only a fraction of reproductive problems in stallions is confined to chromosomal abnormalities (Das et al 2012;Ruiz et al 2019;Raudsepp 2020), suggesting that the majority of genetic factors contribute at DNA sequence level.…”

Section: Introductionmentioning

confidence: 99%

Thoroughbred stallion fertility is significantly associated with FKBP6 genotype but not with inbreeding or the contribution of a leading sire

et al. 2021

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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 highthroughput 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 breedspecific haplotype with genetic variants unique to Thoroughbreds. Further WGS-based research is needed to identify the molecular causes underlying the observed genotypephenotype association in Thoroughbred stallions.

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Genetics of Equine Reproductive Diseases

Cited by 10 publications

References 69 publications

The G-Protein-Coupled Membrane Estrogen Receptor Is Present in Horse Cryptorchid Testes and Mediates Downstream Pathways

The G-Protein-Coupled Membrane Estrogen Receptor Is Present in Horse Cryptorchid Testes and Mediates Downstream Pathways

Horse Clinical Cytogenetics: Recurrent Themes and Novel Findings

Thoroughbred stallion fertility is significantly associated with FKBP6 genotype but not with inbreeding or the contribution of a leading sire

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