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In dairy farm animals, the principal goal of the selection is the improvement of milk yield and composition. The genes of milk proteins and hormones are excellent candidate genes for linkage analysis with quantitative trait loci (QTL) because of their biological significance on the quantitative traits of interest.Prolactin (PRL) is a polypeptide hormone with multiple functions, secreted mainly by the anterior pituitary gland. Prolactin's biological activity consists of various roles in the reproduction, lactation and a number of homeostatic biological functions including immune functions.Casein proteins and their genetic variants have been reported as important factors associated with lactation performance, milk composition and cheese yield efficiency. Genetic variants of bovine kappa-casein (K-CN) gene are associated with milk protein content and have a significant influence on rennet clotting time, firmness and cheese yield of milk.The pituitary-specific transcription factor (PIT-1) gene is responsible for pituitary development and hormone secreting gene expression in mammals. PIT-1 is studied as a candidate genetic marker for growth, carcass and also for milk yield traits.Genomic DNA extracted from 100 healthy buffaloes was amplified using primers that were designed from the cattle PRL, K-CN and PIT-1 gene sequences. The amplified fragments of PRL (294-bp), K-CN (530-bp) and PIT-1 (451-bp) were digested with RsaI, HindIII and HinfI restriction enzymes, respectively. The results showed that all tested buffaloes are genotyped as GG for PRL, BB for K-CN and BB for PIT-1.

A 721-bp fragment from 15,541 to 16,261 bp (NC_001941.1) of the mtDNA control region from different Egyptian and Italian sheep breeds was amplified. The PCR products were purified and sequenced. From the amplified fragment of 721-bp, a region of 423 bp after excluding a central region rich in tandem repeats was analyzed.Within all tested breeds, the haplotype diversity and average number of pairwise differences were 0.97571 and 7.01484, respectively. The genetic distances (D) and the average number of pairwise differences (Dxy) between breeds were estimated. The lowest distance was observed between Laticauda and Italian Muflon followed by distance between Sarda and Italian Muflon while the highest distance was observed between Barki and Sarda followed by distance between Barki and Laticauda.Phylogenetic analysis showed the presence of three haplogroups -HapA, HapB and HapC -in the examined samples with the absence of other two haplogroups HapD and HapE. All Italian samples cluster with B haplogroup and also in the Egyptian breeds the most dominant haplogroup was B (62 out of 67 analyzed samples). In Egyptian Barki breed one individual clusters with A haplogroup and another individual with C haplogroup. In Ossimi breed two individuals cluster with C haplogroup and in Rahmani there is one sample belonging to A haplogroup.The matrix of pairwise differences among breeds was used to perform a Principal Component Analysis (PCA). This analysis showed that the Italian breeds are clearly separated from the Egyptian breeds; moreover the Egyptian Barki breed is separated from Ossimi and Rahmani.ª 2015 Production and hosting by Elsevier B.V. on behalf

Insulin-like growth factor binding protein-3 (IGFBP-3) gene is a structural gene responsible for the multiple influences of insulin-like growth factors (IGFs) system. It is considered as a candidate gene for growth and production traits. In the present study, we aimed to determine the genetic polymorphism of Egyptian cattle IGFBP-3 gene.The amplified fragment of cattle IGFBP-3 gene at 651-bp was digested with three different endonucleases; HaeIII, MspI and TaqI. The digestion of the PCR products with MspI and TaqI endonucleases revealed similar restriction patterns in all tested animals.Digestion of the PCR product with HaeIII restriction enzyme revealed three different genotypes in Egyptian cattle due to the presence of two alleles; allele A with 7 digested fragments resulting from the presence of 6 restriction sites and allele C with 8 digested fragments resulting from the presence of 7 restriction sites; six sites as allele A in the addition of another restriction site at position 298^299 as a result of SNP (A fi C) in C allele at position 299. The restriction patterns of IGFBP-3/HaeIII showed that forty-six examined animals are genotyped as AA, CC and AC with frequencies of 21.74%, 21.74% and 56.52%, respectively.It is concluded that the IGFBP-3/HaeIII polymorphism may be utilized as a good marker for genetic differentiation between cattle animals for different body functions such as growth, metabolism, reproduction, immunity and energy balance. The nucleotide sequences of Egyptian cattle IGFBP-3 A and C alleles were submitted to GenBank with the accession numbers KF899893 and KF899894, respectively. ª 2014 Production and hosting by Elsevier B.V. on behalf