Final answer:
A gene is a specific segment of DNA that provides the genetics for one specific trait. There can be different versions of a gene known as alleles. For example, in humans, the blood type trait is determined by the two alleles of the marker gene that are inherited.
Step-by-step explanation:
A gene is a specific segment of DNA that provides the genetics for one specific trait. It is the fundamental unit of inheritance and carries the instructions for the development and functioning of the organism. Genes exist in pairs on chromosomes, and each gene has different versions called alleles. A specific segment of DNA that provides the genetic information for one specific trait is called a gene. Genes are the functional units of heredity and contain instructions for the synthesis of proteins or functional RNA molecules, which play roles in determining various traits and characteristics of an organism.
For example, in humans, there are three possible gene sequences on the chromosome that determine blood type: sequence A, sequence B, and sequence O. The blood type trait is determined by the two alleles of the marker gene that are inherited. It is possible to have two copies of the same gene sequence on both homologous chromosomes, with one on each, or two different sequences.