Chromosomes are the carriers of genetic material and chromosome mutations are crucial sources of genetic variation, we can use these mutations as markers to determine the specific location of a gene on the chromosome, and its position relative to other genes. Cytological markers include chromosome karyotypes, bandings, repeats, deletions, translocations, and inversions. Cytological markersĬytological markers have been used for the assessment of farm animal genetic resources based on the numbers and morphology of animal chromosomes. However, it is still an effective method for the assessment of qualitative traits, for which it is easy to characterize phenotypic differences between individuals through direct observation and measurement. Consequently, the application of morphological markers is limited in the evaluation of quantitative traits. Furthermore, the measurement and identification of animal morphological traits usually takes a long time, and it is not easy to remove the effects of environmental factors. The evaluation of farm animal genetic resources through morphological markers is based on subjective judgments and descriptions, and the conclusions reached are often not completely accurate. However, an animal’s phenotype is determined by its genetic background and the environment it experiences. They are used in the identification, classification, and characterization of genetic evolution of different species or populations.
#Restriction fragment length polymorphism rflp skin#
coat color, body shape, skin structure, and anatomical characteristics), which can be obtained by direct visual observation and measurement. Morphological markers normally refer to external animal characteristics (i.e. Conventional methods applied to AnGR assessments Morphological markers The following is a brief summary on the principles and advancements of primary genetic markers involved in assessments of Animal Genetic Resources (AnGR). The expansion in DNA information will facilitate study of genome-wide diversity such information is much more precise for the assessment of genetic diversity than previous markers. They overcome the limitations of morphological, cytological, and biochemical markers, namely the small numbers of such markers and the fact they can be environmentally influenced. At present, DNA molecular marker techniques are widely applied in the fields of germplasm identification, phylogenetics, and genetic structural analysis. In addition, with biotechnological and computer innovations, novel strategies such as whole-genome SNP chips and DNA Barcoding have emerged. All of these DNA-based markers contain specific advantages and have played significant roles in the evaluation of genetic diversity in farm animals. Restriction Fragment Length Polymorphism (RFLP), Random Amplified Polymorphic DNA (RAPD), Amplified Fragment Length Polymorphism (AFLP), Single-Strand Conformation Polymorphism (SSCP) and Microsatellite DNA. By the 1980s, many different types of DNA molecular markers had been explored, e.g. With the rapid development of modern biotechnology, biochemical markers, such as proteins and isozymes, were utilized. In earlier studies, morphological markers and eco-geographical factors were used to represent diversity, and after that, chromosomal karyotyping was developed. However, sufficient genetic markers for evaluating the population structure and other aspects of available animal genetic resources are necessary to assess genetic diversity. Mankind can learn and make use of these special genetic resources to develop animal production for human food needs. Collectively, these characteristics constitute the Earth’s species diversity. The development of every species under its particular natural ecosystem, environmental, and socio-economic conditions has led to each having its own specific genetic characteristics.
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