| Abstract: |
The present investigation was designed to study the genetic diversity and similarity among sheep breeds on the level of chromosomal banding and use of microsatellites BM1329 and OarAElOl as specific markers for the introgression of the FecB locus into different sheep breeds to find out polymorphism pattern of the Egyptian sheep FecB gene and compare it with those of foreign sheep breeds in order to identify the genotype of this gene in these breeds which will help in genetic improvement.Metaphase spread and detailed G-band karyotypic profiles and detailed ideogram of the seven sheep breeds revealed that, the diploid number of chromosomes was 2n = (54 XX) chromosomes present in 27 homologous pairs, of which divided into two types of chromosomes according to the site of the centromere; three pairs of metacentric chromosomes and 24 pairs of acrocentric chromosomes. There is one pair of chromosomes called sex chromosomes (XX) were represented by the largest acrocentric pair. Hierarchical cluster analysis and pearson correlation matrix among accessions were performed for combining of the whole cytological attributes (average number of bands, average chromosome length, average chromosome area, average total length of long arm of chromosomes and average total length of short arm of chromosomes) reveled that there were a high similarity of (1.00) between Farafra and Seedy breeds, also, Romanov and CB1, as well as Finnsheep and CB2, followed by a relative high similarity of (0.998) between CB1 and Romanov breed with Rahmany breed. CB2 and Finnsheep breeds varied from all the other breeds by the lowest similarity detected of (0.978).During the analysis with OarAE101 primer of seven sheep breeds four alleles were obtained, allele 125, allele 113, allele 123 and allele 97 with frequencies of (0.18), (0.54), (0.016) and (0.23), respectively in relation to this microsatellite.Also, Four alleles were obtained using microsatellite BM1329during the analysis of the seven sheep breeds; allele 136, allele 144, allele 162 and allele 188 with frequencies of (0.008), (0.06), (0.32) and (0.57) respectively in relation to this microsatellite.In Egyptian sheep breeds; this study improved the absence of FecB allele from all animals belonging to the Egyptian sheep breeds.The polymerase chain reaction using microsatellite markers BM1329 and OarAElOl that linked to FecB allele resulted in carrier of 97bp and 162bp bands which linked to the FecB allele in foreign sheep breedsThis study explains that the incorporation of foreign sheep breeds genes into native Egyptian breeds will improve both biological and economic efficiency under annual or accelerated lambing systems and help to increase of expression of this gene in the local Egyptian breed without affect on the acclimatization traits of these breeds to the environmental conditions in Egypt.
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