Genomics is the study of genomes, the complete set of DNA within a cell of an organism. More specifically, genomics involves the sequencing and analysis of genomes. Genomics is also concerned with the structure, function, evolution, and mapping of genomes. In contrast to genetics, which refers to the study of individual genes and their roles in inheritance, genomics uses high DNA sequencing and bioinformatics to assemble, and analyze the function and structure of entire genomes. The field also includes studies of intragenomic phenomena such as heterosis, epistasis, pleiotropy and other interactions between loci and alleles within the genome. Advances in genomics have triggered a revolution in systems biology which facilitates the understanding of complex biological systems such as the brain.