Although genetics has its roots back in the 19th century with the work of Gregor Mendel and other pioneering scientists,but medical molecular genetics emerged much later.The genetic architecture of common diseases is an important factor in determining the extent to which patterns of genetic variation influence group differences in health outcomes.Medical molecular genetics is the application of genetic research to medicine in a broad and varied field.It encompasses many different individual fields,including clinical genetics,biochemical genetics,cytogenetics,molecular genetics,the genetics of common diseases and genetic counseling.Each of the individual fields within medical molecular genetics is a hybrid,which leads to the current medical development and promotes the transfer of traditional symptom medicine to true prevention medicine.