Within the field of molecular biology, genomics is the study of genomes, the complete set of genetic material within an organism. Genomics involves the sequencing and analysis of genomes. Genomics is also concerned with the structure, function, comparison, and evolution of genomes. In contrast to genetics, which refers to the study of individual genes and their roles in inheritance, genomics uses high throughput DNA sequencing and bioinformatics to assemble, and analyze the function and structure of entire genomes. The field also includes studies of intragenomic (within the genome) phenomena such as heterosis (hybrid vigour), epistasis (effect of one gene on another), pleiotropy (one gene affecting more than one trait) 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.