The mechanisms of transmission of inherited traits in viruses, bacteria, fungi, plants and animals are discussed. Molecular mechanisms of gene expression and gene regulation are analyzed. Recombinant DNA and cloning of genes and their uses and applications in genetic analysis, biotechnology, forensics, agriculture, medicine, and the pharmaceutical industry are presented. The coding capacity, genes and genomes of diverse organisms for which total DNA sequence information is available are considered. A special topic in human genetics is considered yearly; recent examples are the genetics of cancer, hypercholesterolemia, and human behavioral genetics.