Genomics << jee NOH mihks or jee NOM ihks >> is the study of genes as they exist in living things. A gene is the part of a cell that determines which traits an organism inherits from its parents. The term genome refers to all the genes on a cell’s chromosomes, threadlike structures that consist mainly of the genetic material DNA (deoxyribonucleic acid). One key goal of genomics involves determining the sequence (order) of all genes in the genomes of different species.
Scientists determine genome sequences by isolating and purifying DNA from cells. They then use molecules called restriction enzymes to separate the DNA into fragments. These enzymes break the DNA at points known as cleavage sites. By using combinations of restriction enzymes, researchers can isolate a DNA fragment that contains a single gene. They then analyze the cleavage sites to determine the location of this fragment, and thus the gene, on the chromosome. Powerful computer programs help researchers determine genome sequences. Scientists have identified sequences for such organisms as yeasts, honey bees, chickens, rats, monkeys, chimpanzees; and they have sequenced (determined the order of) the entire human genome.
Genome sequencing has led to a variety of discoveries. For example, by comparing genomes of different species, biologists have more accurately determined how these species are related to one another. Genomics has also aided scientists in sequencing proteomes, or collections of proteins coded within genomes. Proteins carry out the work of cells, and protein sequencing has led to a better understanding of how these molecules function. Scientists can use such knowledge to study the genetic causes of human disease and to better diagnose and treat disease.
