Principles of Genetics and Breeding

1.2.1.2 What is Gene? Where is a Gene?

The genetic determinants of the inherited component of a phenotype or called genes.

• Genes are bits of biochemical instructions found inside the cells of every organism from bacteria to humans. Offspring receive a mixture of genetic information from both parents. This process contributes to the great variation of traits that we see in nature, such as the color of a flower’s petals, the markings on a butterfly’s wings, or such human behavioral traits as personality or musical talent. Geneticists seek to understand how the information encoded in genes is used and controlled by cells and how it is transmitted from one generation to the next. Geneticists also study how tiny variations in genes can disrupt an organism’s development or cause disease. Increasingly, modern genetics involves genetic engineering, a technique used by scientists to manipulate genes.

Genetic information is encoded and transmitted from generation to generation in deoxyribonucleic acid (DNA).

DNA is a coiled molecule organized into structures called chromosomes within cells. Segments along the length of a DNA molecule form genes.

Genes direct the synthesis of proteins, the molecular laborers that carry out all life-supporting activities in the cell. Although all humans share the same set of genes, individuals can inherit different forms of a given gene, making each person genetically unique.

Each cell is surrounded by a thin membrane, in which a small ball called a nucleus is suspended. This ball contains the genes that provide all the information for the cell characteristics.