Native Sheep Breeds in Poland-Importance and Outcomes of Genetic Resources Protection Programmes.

The sheep population of native breeds, despite their unique features and the ability to adapt to harsh environmental conditions, has significantly decreased in recent years. Due to the low profitability of breeding, many local breeds of sheep in Poland were exposed to the risk of extinction. Many years of crisis in sheep farming have exacerbated this situation. The aim of this paper was to present the current situation of native sheep breeding in Poland, in terms of significance and effects of genetic resources protection programmes. The conservation of genetic resources of sheep aims to maintain and increase the population size while striving to maintain the greatest possible genetic variability. There are 17 native breeds included in the Polish sheep genetic resources conservation programme. A positive element of the implementation of the conservation of genetic resources programme for sheep is the accompanying measures which are based on the use of the non-productive role of the species. Extensive sheep grazing, as a form of nature conservation, serves to preserve valuable natural landscapes and the culture of local communities associated with sheep farming. Production and promotion of quality products, especially using niche markets and short production chains, are essential to ensure the economic viability of farms. These activities must be accompanied by raising public awareness of indigenous breeds and their alternative use in environmental activities, as well as their role in preserving the cultural heritage of local communities, for example through mountain grazing and the production of traditional products.

A genome-wide association study for prolificacy in three Polish sheep breeds.

Reproductive traits (especially litter size) are usually characterized by low heritability, and thus, phenotypic selection is often ineffective and slow. In order to improve fertility characteristics such as ovulation rate and litter size, it seems more effective to select breeding animals based on their genotype. The aim of the study was to use genome-wide association study (GWAS) in three sheep breeds to identify the genetic variants affecting the litter size in sheep. The study allowed us to identify one genome-wide significant SNP (rs402032081-located in ephrin type-A receptor 6, EPHA6) showing an association with litter size in Polish Mountain Sheep. We suggest that the EPHA6 gene can be a candidate gene for prolificacy trait in selected breeds of sheep; however, it needs further functional data for validation.

Genotyping-by-sequencing performance in selected livestock species.

Application of next generation sequencing for large scale genotyping in livestock is limited by high costs and challenging data analysis process. However, available restriction enzyme-based enrichment techniques like e.g. genotyping-by-sequencing (GBS) are promising tools allowing reduction of financial outlies by a high sample multiplexing and narrowing down the sequenced genome areas to the randomly distributed read tags. In this study, we tested the performance of standard, PstI endonuclease-adapted GBS protocol for population genetics in cattle, horse and sheep with application of different, including low-depth sequencing setups. It was found that the detected SNPs display desirable polymorphism parameters and are evenly scattered across the whole genome including gene coding regions. It was also shown that the SNPs can be successfully applied in population genetics, revealing the genetic differentiation of the studied breeds. The GBS approach represents a cost-effective alternative to existing genotyping methods which may find adoption in various research applications.

Kidney injury by cyclosporine A is aggravated in heme oxygenase-1 deficient mice and involves regulation of microRNAs.

Cyclosporine A (CsA), a widely used immunosuppressive drug, exerts nephrotoxic activities, as demonstrated by increased tubulointerstitial fibrosis, inflammation and podocyte damage. Recently, a number of microRNAs expressed in the kidney have been reported to be elevated during renal damage. Our aim was to investigate the effect of CsA on selected microRNAs in the mouse kidney after CsA treatment. Moreover, as heme oxygenase-1 (HO-1, encoded by the Hmox1 gene) was shown to play a protective role during kidney disorders, we assessed whether HO-1 deficiency in vivo influences the CsA-regulated microRNAs' expression. We have observed that the pro-fibrotic miR-21 and pro-apoptotic miR-34a expression was upregulated in kidneys of HO-1 deficient mice and it was further enhanced by CsA. Concomitantly, the level of anti-fibrotic microRNAs, belonging to miR-29 and miR-200 families, was down-regulated after CsA treatment. Generally, Hmox1 knock-out (Hmox1-/-) animals were more susceptible to CsA treatment, as the mortality rate was 4 out of 9 Hmox1-/- mice, and increased fibrosis (Tgfb2, Pai1), inflammation (Il6) and apoptosis (Cdkn1a-p21) were noticed in the HO-1 deficient kidneys. In summary, our data demonstrate that CsA induces significant changes in the expression of renal microRNAs and emphasize HO-1 deficiency as an important factor contributing to the CsA-mediated renal toxicity.