Phylogenetic relationships and genetic variation in Iranian Afshari sheep breed were analyzed using 12S rRNA and 16S rRNA gene sequences. The genomic DNA was isolated by salting out method and amplified 12S rRNA and 16S rRNA genes using PCR method. PCR amplification of 12S and 16S rRNA generated PCR amplicons at 859 and 1053 bp lengths, respectively. Sequence analysis was performed using BioEdit software. Phylogenetic tree was constructed using MEGA software. Phylogenetic analysis of haplotype in the combination with the sheep from GenBank showed that Iranian Afshari sheep made a close to the Australian sheep cluster. This study was found informative for establishing relationships between breeds from different parts of the world. This study may facilitate the future researchers and breeders for better understanding the genetic interactions and breed differentiation for devising future breeding and conservation strategies to preserve the rich animal genetic reservoir of the country.
Genetic introgression from interbreeding hybridization of European Bos taurus taurus (EBT) and Indian Bos taurus indicus (IBI) cattle breeds have been widely used to combine the climatic resilience of the IBI cattle and the higher productivity of EBT when forming new composite beef cattle (CB) populations. The subsequent breeding strategies have shifted their initial genomic compositions. To uncover population structure, signatures of selection, and potential introgression events in CB populations, high-density genotypes [containing 492,954 single nucleotide polymorphisms (SNPs) after the quality control] of 486 individuals from 15 cattle breeds, including EBT, IBI, and CB populations, along with two Bos grunniens genotypes as outgroup were used in this study. Then, in-depth population genetics analyses were performed for three CB breeds of Beefmaster, Brangus, and Santa Gertrudis. Neighbor-joining, principal components, and admixture analyses confirmed the historical introgression of EBT and IBI haplotypes into CB breeds. The fdM statistics revealed that only 12.9% of CB populations’ genetic components are of IBI origin. The results of signatures of selection analysis indicated different patterns of selection signals in the three CB breeds with primary pressure on pathways involved in protein processing and stress response in Beefmaster, cell proliferation regulation and immune response in Brangus, and amino acids and glucose metabolisms in Santa Gertrudis. An average of >90% of genomic regions underlying selection signatures were of EBT origin in the studied CB populations. Investigating the CB breeds’ genome allows the estimation of EBT and IBI ancestral proportions and the locations within the genome where either taurine or indicine origin alleles are under selective pressure. Such findings highlight various opportunities to control the selection process more efficiently and explore complementarity at the genomic level in CB populations.
To estimate economic values (EVs) of seven important traits including pregnancy rate (PR), litter size (LS), lamb weight at birth (BW0), three (weaning; BW3), six (BW6) and nine (BW9) months weight and survival rate until the age of 6 months (SR) in Zel sheep under an intensive production system in Mazandaran province of Iran, data from two farms were analysed using a bio-economic model. Variable costs accounted for about 99% of the total costs and the feed costs had the highest proportion with 72.54%. Among the income sources, the sale of surplus animals formed 81.4% of the total revenues. The EVs were estimated as the amount of change in the profit of the system after each trait mean increased by both 1% and one unit, while all other traits were constant at their mean values. The most important trait in this system was LS, followed by SR, PR, BW9, BW3, BW6 and BW0 respectively. The sensitivity of EVs was investigated by changing prices of feed and live weight of 9-month-old lambs by ±20%. Results showed that the EV of BW9 was the most constant and EV of BW0 was the most variable. As the prices of feed and live weight of 9-month-old lambs were simultaneously changed by ±20%, the variation in the EVs decreased and they showed more consistency. This study showed that the profitability in an intensive production system of Zel sheep could be increased by improving LS, SR, PR and BW9.
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