Molecular genetics is the field of biology and genetics that studies the structure and function of genes at a molecular level. Molecular genetics employs the methods of genetics and molecular biology to elucidate molecular function and interactions among genes. It is so-called to differentiate it from other sub fields of genetics such as ecological genetics and population genetics.
Along with determining the pattern of descendants, molecular genetics helps in understanding genetic mutations that can cause certain types of diseases. Through utilizing the methods of genetics and molecular biology, molecular genetics discovers the reasons why traits are carried on and how and why some may mutate.
Read more about Molecular Genetics: Forward Genetics, Reverse Genetics, Gene Therapy, Techniques in Molecular Genetics, The Human Genome Project