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Background: A single nucleotide polymorphism (SNP) in the first intron of the myostatin gene (MSTN) is associated with aptness of elite Thoroughbreds to race over sprint, middle or long distances. This intronic marker (g.66493737 T ≻ C), a short interspersed nuclear element (SINE) of 227 bp (Ins227bp) insertion polymorphism in the MSTN promoter, and the adjacent SNP BIEC2-417495 have not been studied for their association with racing aptness of the average Thoroughbreds raced in countries with lower status of the racing industry. This study investigated these markers regarding their prevalence and association with performance in common race horses. Markers were genotyped by amplification refractory mutation system-quantitative PCR (ARMS-qPCR) or amplicon melting. Furthermore, we asked whether the Ins227bp marker might theoretically regulate the expression of myostatin by generating a novel target for DNA methylation or by changing binding sites for transcription factors. Putative sites for DNA methylation or binding of transcription factors were predicted by MethPrimer and by the softwares JASPAR, MatInspector and UniPROBE, respectively. Results: Pairwise linkage disequilibrium between g.66493737 T ≻ C and Ins227bp was high (r² = 0.93). A lower linkage was determined for g.66493737 T ≻ C and BIEC2-417495 (r² = 0.69) as well as for BIEC2-417495 and Ins227bp (r² =0.76). The estimated frequencies for the presence of Ins227bp (I) indel and the C alleles at g.66493737 T ≻ C and BIEC2-417495 were 0.46, 0.47 and 0.43, respectively. Heterozygotes represented the most abundant genotype at each locus. The best racing distance (BRD) was significantly different between the homozygotes of each SNP (p = 0.01 to 0.03). C allele homozygotes at BIEC2-417495 or g.66493737 T ≻ C, as well as Ins227bp homozygotes earned most money on a mean distance ranging from 1211 to 1230 m. Heterozygotes earned most money on races over 1690 to 1709 m. The BRD for the T/T carriers at both SNP loci and for the SINE-free genotype was 1812 to 1854 m. Other performance parameters were not significantly different between the genotypes, except of the relative success score (RSS). The RSS was significantly slightly better on a distance of ≤1300 m for all carriers of the C allele and the Ins227bp compared to homozygous T genotypes and SINE-negative horses (p = 0.037 to 0.046). For distances of more than 1300 m the RSS was not significantly different between genotypes. In silico assessment indicated that the Ins227bp promoter insertion might have generated a CpG island and a few novel putative binding sites for transcription factors. Conclusions: All three target polymorphisms (Ins227bp, g.66493737 T ≻ C, BIEC2-417495) are suitable markers to assess the ability of non-elite Thoroughbreds to race at short or longer distances. The CpG island generated by Ins227bp may cause training-induced silencing of MSTN expression. [ABSTRACT FROM AUTHOR]

Background: The mitochondrial DNA (mtDNA) of the cloned sheep "Dolly" and nine other ovine clones produced by somatic cell nuclear transfer (SCNT) was reported to consist only of recipient oocyte mtDNA without any detectable mtDNA contribution from the nucleus donor cell. In cattle, mouse and pig several or most of the clones showed transmission of nuclear donor mtDNA resulting in mitochondrial heteroplasmy. To clarify the discrepant transmission pattern of donor mtDNA in sheep clones we analysed the mtDNA composition of seven fetuses and five lambs cloned from fetal fibroblasts. Results: The three fetal fibroblast donor cells used for SCNT harboured low mtDNA copy numbers per cell (A: 753 ± 54, B: 292 ± 33 and C: 561 ± 88). The ratio of donor to recipient oocyte mtDNAs was determined using a quantitative amplification refractory mutation system (ARMS) PCR (i.e. ARMS-qPCR). For quantification of SNP variants with frequencies below 0.1% we developed a restriction endonuclease-mediated selective quantitative PCR (REMS-qPCR). We report the first cases (n = 4 fetuses, n = 3 lambs) of recipient oocyte/nuclear donor mtDNA heteroplasmy in SCNT-derived ovine clones demonstrating that there is no species-effect hindering ovine nucleus-donor mtDNA from being transmitted to the somatic clonal offspring. Most of the heteroplasmic clones exhibited low-level heteroplasmy (0.1% to 0.9%, n = 6) indicating neutral transmission of parental mtDNAs. High-level heteroplasmy (6.8% to 46.5%) was observed in one case. This clone possessed a divergent recipient oocyte-derived mtDNA genotype with three rare amino acid changes compared to the donor including one substitution at an evolutionary conserved site. Conclusion: Our study using state-of-the-art techniques for mtDNA quantification, like ARMSqPCR and the novel REMS-qPCR, documents for the first time the transmission of donor mtDNA into somatic sheep clones. MtDNA heteroplasmy was detected in seven of 12 clones tested, whereby all but one case revealed less than 1% mtDNA contribution from the nuclear donor cell suggesting neutral segregation. [ABSTRACT FROM AUTHOR]

Background: A single nucleotide polymorphism (SNP) in the first intron of the myostatin gene (MSTN) is associated with aptness of elite Thoroughbreds to race over sprint, middle or long distances. This intronic marker (g.66493737 T ≻ C), a short interspersed nuclear element (SINE) of 227 bp (Ins227bp) insertion polymorphism in the MSTN promoter, and the adjacent SNP BIEC2-417495 have not been studied for their association with racing aptness of the average Thoroughbreds raced in countries with lower status of the racing industry. This study investigated these markers regarding their prevalence and association with performance in common race horses. Markers were genotyped by amplification refractory mutation system-quantitative PCR (ARMS-qPCR) or amplicon melting. Furthermore, we asked whether the Ins227bp marker might theoretically regulate the expression of myostatin by generating a novel target for DNA methylation or by changing binding sites for transcription factors. Putative sites for DNA methylation or binding of transcription factors were predicted by MethPrimer and by the softwares JASPAR, MatInspector and UniPROBE, respectively., Results: Pairwise linkage disequilibrium between g.66493737 T ≻ C and Ins227bp was high (r (2) = 0.93). A lower linkage was determined for g.66493737 T ≻ C and BIEC2-417495 (r (2) = 0.69) as well as for BIEC2-417495 and Ins227bp (r (2) = 0.76). The estimated frequencies for the presence of Ins227bp (I) indel and the C alleles at g.66493737 T ≻ C and BIEC2-417495 were 0.46, 0.47 and 0.43, respectively. Heterozygotes represented the most abundant genotype at each locus. The best racing distance (BRD) was significantly different between the homozygotes of each SNP (p = 0.01 to 0.03). C allele homozygotes at BIEC2-417495 or g.66493737 T ≻ C, as well as Ins227bp homozygotes earned most money on a mean distance ranging from 1211 to 1230 m. Heterozygotes earned most money on races over 1690 to 1709 m. The BRD for the T/T carriers at both SNP loci and for the SINE-free genotype was 1812 to 1854 m. Other performance parameters were not significantly different between the genotypes, except of the relative success score (RSS). The RSS was significantly slightly better on a distance of ≤ 1300 m for all carriers of the C allele and the Ins227bp compared to homozygous T genotypes and SINE-negative horses (p = 0.037 to 0.046). For distances of more than 1300 m the RSS was not significantly different between genotypes. In silico assessment indicated that the Ins227bp promoter insertion might have generated a CpG island and a few novel putative binding sites for transcription factors., Conclusions: All three target polymorphisms (Ins227bp, g.66493737 T ≻ C, BIEC2-417495) are suitable markers to assess the ability of non-elite Thoroughbreds to race at short or longer distances. The CpG island generated by Ins227bp may cause training-induced silencing of MSTN expression.

Background: The oomycete Aphanomyces astaci is regarded as the causative agent of crayfish plague and represents an evident hazard for European crayfish species. Native crayfish populations infected with this pathogen suffer up to 100% mortality. The existence of multiple transmission paths necessitates the development of a reliable, robust and efficient test to detect the pathogen. Currently, A. astaci is diagnosed by a PCR-based assay that suffers from cross-reactivity to other species. We developed an alternative closed-tube assay for A. astaci, which achieves robustness through simultaneous amplification of multiple functionally constrained genes., Results: Two novel constitutively expressed members of the glycosyl hydrolase (GH18) gene family of chitinases were isolated from the A. astaci strain Gb04. The primary amino acid sequence of these chitinase genes, termed CHI2 and CHI3, is composed of an N-terminal signal peptide directing the post-translational transport of the protein into the extracellular space, the catalytic GH18 domain, a proline-, serine-, and threonine-rich domain and a C-terminal cysteine-rich putative chitin-binding site. The A. astaci mycelium grown in a pepton-glucose medium showed significant temporal changes in steady-state CHI2 and CHI3 mRNA amounts indicating functional constraint. Their different temporal occurrence with maxima at 48 and 24 hours of incubation for CHI2 and CHI3, respectively, is in accordance with the multifunctionality of GH18 family members. To identify A. astaci-specific primer target sites in these novel genes, we determined the partial sequence homologs in the related oomycetes A. frigidophilus, A. invadans, A. helicoides, A. laevis, A. repetans, Achlya racemosa, Leptolegnia caudata, and Saprolegnia parasitica, as well as in the relevant fungi Fusarium solani and Trichosporon cutaneum. An A. astaci-specific primer pair targeting the novel genes CHI2 and CHI3 as well as CHI1 - a third GH18 family member - was multiplexed with primers targeting the 5.8S rRNA used as an endogenous control. A species was typed unambiguously as A. astaci if two peaks were concomitantly detected by melting curve analysis (MCA). For sensitive detection of the pathogen, but also for quantification of agent levels in susceptible crayfish and carrier crayfish, a TaqMan-probe based real-time PCR (qPCR) assay was developed. It targets the same chitinase genes and allows quantification down to 25 target sequences., Conclusion: The simultaneous qualitative detection of multiple sequences by qPCR/MCA represents a promising approach to detect species with elevated levels of genetic variation and/or limited available sequence information. The homogenous closed-tube format, reduced detection time, higher specificity, and the considerably reduced chance of false negative detection achieved by targeting multiple genes (CHI1, CHI2, CHI3, and the endogenous control) at least two of which are subject to high functional constraint, are the major advantages of this multiplex assay compared to other diagnostic methods. Sensitive quantification achieved with TaqMan qPCR facilitates to monitor infection status and pathogen distribution in different tissues and can help prevent disease transmission.