Association between single nucleotide polymorphism in ovine Calpain gene and growth performance in three Egyptian sheep breeds.

The aim of the present study was to assess the association of single nucleotide polymorphisms (SNPs) of Calpain (CAPN) gene with birth weight (BW), final weight (FW) and average daily gain (ADG) in three Egyptian sheep breeds: Barki, Rahmani and Ossimi. Blood samples were collected from 108 animals representing the three breeds. DNA was isolated using salting out procedure and then the quality and quantity of DNA extracted were measured. A 190 bp of CAPN was amplified by PCR using specific primers. The allele and genotype frequencies for all the identified SNPs were calculated. The PCR products corresponding to each genotype were sequenced to identify SNPs associated with the traits in question. Two SNPs (C→T) were detected in the nucleotides 44 and 154. For each SNP, the two mentioned alleles were named C and T, respectively. The sequenced CAPN segments were subjected to nucleotide blast at NCBI, which revealed 99% identity with that reported for sheep in Genbank. The TT was the least common genotype, whereas frequencies of CT and CC genotypes were fluctuated in the three sheep breeds under study. Animal carrier TT genotype had higher BW, FW and ADG than those with CT genotype, while the lowest values were associated with CC genotype. For the three traits under study, Rahmani had the highest estimates followed by Ossimi and Barki. Males exhibited heavier BW and FW as well as higher ADG compared with females. The results generated provide preliminary indication of the functional diversity present in Barki, Rahmani and Ossimi sheep and the possibility of using this polymorphism in Egyptian sheep genetic improvement.

Genotoxic evaluation for the estrogenic mycotoxin zearalenone.

Genotoxic effects of the mycotoxin Zearalenone (ZEN) were evaluated on albino mice. The investigation was assessed using 4 criteria: chromosome aberrations in bone marrow and spermatocytes of adult male mice; chromosome analysis and teratological effects of mice embryos. Zearalenone was administrated to both adult males and pregnant females with 2 doses level (5 microg x kg(-1) and 10 microg x kg(-1) ZEN). Zearalenone was found to reduce the mitotic activity in treated males and the embryos proving that it is a cytotoxic substance. In treated males and females, it induced some chromosome abnormalities with no significant increase over the control at the doses investigated, except for some few figures. Similar results were observed for the teratological study. The results in general could consider zearalenone as a toxic mycotoxin for both adult animals and embryos. It is highly recommended that a great attention should be paid towards the toxicity of zearalenone to mono-gastric animals and human, especially it contaminate corn that is widely used in human and animal feeding.

Microdissected bovine X chromosome segment delineates homoeologous chromosomal regions in sheep, goat and buffalo.

The terminal part of the long arm of the bovine X chromosome (bands Xq41-q43) was microdissected. The DNA thus obtained was PCR amplified, labelled and used as painting probe on cattle, sheep, goat and buffalo chromosomes. In cattle, as expected, distinct hybridization signals were observed on bands Xq41-q43. In sheep and goat, the painting signals were observed on the proximal part of the long arm of the X chromosome, adjacent to the centromere (Xp12-q12). In buffalo, however, the terminal part of the X chromosome involving bands q44-q47 was painted. The findings contribute towards developing a better understanding of the comparative organization of the X chromosome in the four bovidae species. Proposed models of evolutionary rearrangements within the X chromosome of the four species are examined in light of the results obtained.

Mapping of the interferon gamma (IFNG) gene in river and swamp buffaloes by in situ hybridization.

In situ hybridization technique was applied using a tritiated (3H) bovine IFNG cDNA probe to regionally localize the gene on river and swamp buffalo chromosomes. The hybridization signals peaked on the 4q23-->q26 bands in river buffaloes and on the 1p24-->p26 bands in swamp buffaloes. The results are compared to the localization of the same gene in cattle. Possible evolutionary conservation in the Bovidae is discussed.

Regional localization of the bovine interleukin-2 (IL2) gene to chromosome 17q22-->q23 by in situ hybridization.

The interleukin-2 (IL2) gene was localized to the q22-->q23 bands of chromosome 17 in cattle using radioactive in situ hybridization. The localization confirms the recent provisional assignment of syntenic group U23 to this bovine chromosome. Increasing evidence for chromosomal banding and gene location homology within the Bovidae suggests that the IL2 gene most likely also maps to chromosome 17 in sheep, goats and buffaloes.