Genetics is the branch of biology concerned with the science of heredity, or the transfer of specific characteristics from one generation to the next. Genetics focuses primarily on genes, coded units found along the DNA molecules of the chromosomes, housed by the cell nucleus. Together, genes make up the blueprints that determine the entire development of the species of organisms down to the specific traits, such as the color of eyes and hair. Geneticists are concerned with two primary areas of gene study: how genes are expressed and regulated in the cell and how genes are copied and passed on to successive generations. Although the science of genetics dates back at least to the nineteenth century, little was known about the exact biological makeup of genes until the 1940s. Since that time genetics has moved to the forefront of biological research. Scientists are now...