الفهرس 
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Abstract
Summary& Conclusion
In this work, Microsatellite DNA repeat (STRs) length polymorphisms were investigated to develop an accurate method for shepherd-dog parentage testing in Egypt, STR markers are a well-known effective, and powerful tool widely used to investigate the genetic structure and diversity of organism strains in general and in animals in particular. We used STRs markers to determine whether samples taken from dogs’ buccal mucosa would be adequate for DNA extraction, to determine whether the paternity of each puppy can be identified from its DNA, and to evaluate the use of the amelogenin gene locus in PCR assays to determine the sex of puppies.
This study was conducted in the genome unit at the Animal Health Research Institute (AHRI) in Dokki, in Cairo, under the supervision of the research team at the center, and before starting the test, our verified measurement realization of STRs markers that were recommended through the International Animal Inheritance Association, by conducting tests on unknown DNA samples on the blinding system (not defined by any information about it with researchers), and it was sent to the ISAG to match it, and the test results were approved. The unit obtained a Passing Certificate and the approvement of the accuracy of the analysis.
DNA was purified by using a DNA extraction kit and quantified by a nanoDROP spectrophotometer. After confirming DNA purity, PCR was carried out by DNA master mix kit (Thermo Scientific’s Canine Genotypes™ Panel 1.1 kit) following the manufacturer guidelines with the Amelogenin gene marker for gender determination. We assessed the use of 18 STRs previously reported for parentage testing in 131 shepherds three dog breeds, Caucasian, German, and King, and reference breeds for the verification and efficiency of STR markers in paternity, inbreeding coefficients, genetic structure, and stock diversity by detecting the degree of genetic heterozygosity.
The allelic frequencies of the markers were used to determine the mean degree
The observed heterozygosity (HO) and expected heterozygosity (HE) ranged from 64% to 64.5%, inbreeding coefficient 5.2%, PIC from 0.419 to 0.689, paternity exclusion probabilities (PE) from 0.99991 to 0.99998, and the combined PE. PD for all markers in all breeds reached high levels of 0.766 (close to 1.0). In Caucasian, King, German, and reference Shepherd retrievers, the final total PEs were 0.99995, 0.99975, 99998, and 0.99991, respectively.
No information is available regarding genetic variation among the most popular breeds of dogs in Egypt. Analysis of STRs markers provides valuable information about genetic diversity and is an effective technique for dog parentage testing. A panel of 21 markers is recommended for parentage testing in domestic dogs by ISAG. According to this study, the 18-STRs-DNA breed test markers can provide an in-depth analysis of a dog’s heritage and lineage. The data presented in this research can be used to monitor and analyze pedigrees.