Genes are sections of DNA that code for a particular trait. Genes are

The set of information that controls a trait; a segment DNA on a chromosome that codes for a specific trait. An abnormal condition that a person inherits through genes or chromosomes. Deoxyribonucleic acid; the genetic material that carries information about an organism and is passed on from parent to offspring.

The question is incomplete but by the understanding of gene it can be defined as:

Answer:

Genes can be defined as the segments of the DNA that contains the code for the specific type of protein.

It functions in one or more type of cells in the body. Different genes are functional in different cells of the body.

The genes that are functional in the heart are not functional in the liver and likewise different organs of the body has different functional genes.