Molecular genetics is the field of biology and genetics that studies the structure and function of genes at a molecular level. The study of chromosomes and gene expression of an organism can give insight into heredity, genetic variation, and mutations. A mutation in a gene can cause encoded proteins and the cells that rely on those proteins to malfunction. Conditions related to gene mutations are called genetic disorders. However, altering a patient’s genes can sometimes be used to treat or cure a disease as well. Gene therapy can be used to replace a mutated gene with the correct copy of the gene, to inactivate or knockout the expression of a malfunctioning gene, or to introduce a foreign gene to the body to help fight disease. Major diseases that can be treated with gene therapy include viral infections, cancers, and inherited disorders, including immune system disorders. This is useful in the study of developmental biology and in understanding and treating genetic diseases.

In the present book, twelve typical literatures about molecular genetics published on international authoritative journals were selected to introduce the worldwide newest progress, which contains reviews or original researches on medical science, genetics, molecular biology, gene engineering, ect. We hope this book can demonstrate advances in molecular genetics as well as give references to the researchers, students and other related people.