Application of multivariate discriminant analysis for differentiation between Saudi sheep (Ovis aries) breeds based on physical and histochemical meat characteristics.

Background and Aim: The multivariate discriminant (MVD) analysis was a successful statistical tool with a discriminatory capacity for tracing sheep breeds based on meat characteristics. Thus, this study aimed to identify three Saudi sheep breeds based on the physical and histochemical aspects of meat using MVD analysis. Materials and Methods: Eight male lambs from each breed, Najdi, Neami, and Harri, were selected randomly at 90 days of age and allocated into three groups for breeding in a completely randomized design. The feeding and rearing management were similar for an experimental period of 90 days. The experimental diet consisted of a concentrated mixture with identical amounts of calories and nitrogen. Fifty-one meat characteristics were measured in the preliminary MVD, representing hot and cold carcass weight, meat cuts and quality measures, body component weights, fat deposit weights, and histochemical characteristics. Results: Out of the total meat characteristics measured, only 19 characteristics had significant discriminant power. The most powerful characteristics were temperature, empty intestinal weight, pH24, external carcass length, heart weight, and L1, based on partial R-square and Wilks' lambda values. The phenotypic associations between the characteristics had strong associations. The obtained principal components efficiently classified the eight individuals of each breed into distinct groups using robust discriminant characteristics. Conclusion: This method allowed us to determine the breed of sheep carcasses and cuts by considering the physical characteristics of the meat. Therefore, butchers and consumers should use scientific techniques for assigning carcasses and meat to their sheep breed after slaughtering.

The wild species genome ancestry of domestic chickens.

BACKGROUND: Hybridisation and introgression play key roles in the evolutionary history of animal species. They are commonly observed within several orders in wild birds. The domestic chicken Gallus gallus domesticus is the most common livestock species. More than 65 billion chickens are raised annually to produce meat and 80 million metric tons of egg for global human consumption by the commercial sector. Unravelling the origin of its genetic diversity has major application for sustainable breeding improvement programmes. RESULTS: In this study, we report genome-wide analyses for signatures of introgression between indigenous domestic village chicken and the four wild Gallus species. We first assess the genome-wide phylogeny and divergence time across the genus Gallus. Genome-wide sequence divergence analysis supports a sister relationship between the Grey junglefowl G. sonneratii and Ceylon junglefowl G. lafayettii. Both species form a clade that is sister to the Red junglefowl G. gallus, with the Green junglefowl G. varius the most ancient lineage within the genus. We reveal extensive bidirectional introgression between the Grey junglefowl and the domestic chicken and to a much lesser extent with the Ceylon junglefowl. We identify a single case of Green junglefowl introgression. These introgressed regions include genes with biological functions related to development and immune system. CONCLUSIONS: Our study shows that while the Red junglefowl is the main ancestral species, introgressive hybridisation episodes have impacted the genome and contributed to the diversity of the domestic chicken, although likely at different levels across its geographic range.

Genetic origin of goat populations in Oman revealed by mitochondrial DNA analysis.

The Sultanate of Oman has a complex mosaic of livestock species and production systems, but the genetic diversity, demographic history or origins of these Omani animals has not been expensively studied. Goats might constitute one of the most abundant and important domestic livestock species since the Neolithic transition. Here, we examined the genetic diversity, origin, population structure and demographic history of Omani goats. Specifically, we analyzed a 525-bp fragment of the first hypervariable region of the mitochondrial DNA (mtDNA) control region from 69 Omani individuals and compared this fragment with 17 mtDNA sequences from Somalia and Yemen as well as 18 wild goat species and 1,198 previously published goat sequences from neighboring countries. The studied goat breeds show substantial diversity. The haplotype and nucleotide diversities of Omani goats were found equal to 0.983 ± 0.006 and 0.0284 ± 0.014, respectively. The phylogenetic analyses allowed us to classify Omani goats into three mtDNA haplogroups (A, B and G): haplogroup A was found to be predominant and widely distributed and accounted for 80% of all samples, and haplogroups B and G exhibited low frequencies. Phylogenetic comparisons with wild goats revealed that five of the native Omani goat populations originate from Capra aegagrus. Furthermore, most comparisons of pairwise population FST values within and between these five Omani goat breeds as well as between Omani goats and nine populations from nearby countries were not significant. These results suggest strong gene flow among goat populations caused by the extensive transport of goats and the frequent movements of human populations in ancient Arabia. The findings improve our understanding of the migration routes of modern goats from their region of domestication into southeastern Arabia and thereby shed light on human migratory and commercial networks during historical times.

The differentiation of camel breeds based on meat measurements using discriminant analysis.

The meat productivity of camel in the tropics is still under investigation for identification of better meat breed or type. Therefore, four one-humped Saudi Arabian (SA) camel breeds, Majaheem, Maghateer, Hamrah, and Safrah were experimented in order to differentiate them from each other based on meat measurements. The measurements were biometrical meat traits measured on six intact males from each breed. The results showed higher values of the Majaheem breed than that obtained for the other breeds except few cases such dressing percentage and rib-eye area. In differentiation analysis, the most discriminating meat variables were myofibrillar protein index, meat color components (L* and a*, b*), and cooking loss. Consequently, the Safrah and the Majaheem breeds presented the largest dissimilarity as evidenced by their multivariate means. The canonical discriminant analysis allowed an additional understanding of the differentiation between breeds. Furthermore, two large clusters, one formed by Hamrah and Maghateer in one group along with Safrah. These classifications may assign each breed into one cluster considering they are better as meat producers. The Majaheem was clustered alone in another cluster that might be a result of being better as milk producers. Nevertheless, the productivity type of the camel breeds of SA needs further morphology and genetic descriptions.

Analysis of genetic diversity and differentiation of sheep populations in Jordan

Background Genetic diversity of sheep in Jordan was investigated using microsatellite markers (MS). Six ovine and bovine MS located on chromosomes 2 and 6 of sheep genome were genotyped on 294 individual from ten geographical regions. Results The number of alleles per locus (A), the expected heterozygosity (He) and observed heterozygosity (Ho) were measured. Overall A, He and Ho were 12.67, 0.820 and 0.684, respectively. On the other hand, genetic distances undoubtedly revealed the expected degree of differentiation among the studied populations. The finding showed closeness of three populations from south (Maan, Showbak and Tafeilah) to each other. Populations from the middle regions of Jordan (Karak, Madaba, Amman, AzZarqa and Mafraq) were found to be in one cluster. Only two populations of the middle region were an exception: AlSalt and Dead Sea. Finally, sheep populations from Irbid were located in separated cluster. It was clear that the studied predefined populations were subdivided from four populations and would be most probably accounted as ancestral populations. These results indicate that number of population is less than the predefined population as ten based on geographical sampling areas. Conclusions The possible inference might be that geographical location, genetic migration, similar selection forces, and common ancestor account for population admixture and subdivision of Awassi sheep breed in Jordan. Finally, the present study sheds new light on the molecular and population genetics of Awassi sheep from different regions of Jordan and to utilize the possible findings for future management of genetic conservation under conditions of climate changes and crossbreeding policy.