Reproduction of these cells is accomplished by the fusion of two sex cells or gametes, termed the ovum and sperm. Each of these gametes contain genes which are the determining factors for hereditary characteristics or traits. The structure within the nucleus, the central region of a cell, which is essential in growth, reproduction, and transmission of the characteristics of a cell, that contains these genes are called chromosomes. DNA is the chemical basis of heredity and carrier of genetic information, which provides the codes needed for its own replication. When a cell reproduces by dividing, its DNA is copied and passed on from one generation to the next.
Individuals inherit their DNA and thus their genes, from their parents.
With the increasing knowledge of genetics, scientists are able to physically manipulate genes to clone genetically identical individuals. A genetic clone results from a group of cells descended from a single cell. It is based on the process of nuclear transfer. When cloning an animal, the unfertilized egg is the cell that is to be genetically copied. The chromosomes containing the encoded DNA are removed from the unfertilized egg.