of inheritance

of inheritance A gene is a basic physical and functional unit of heredity. The concept of the gene was first explained by Gregor Mendel in ’s . He never used the term ‘gene’. He called it ‘factor’. In , the Danish biologist Wilhelm Johannsen, coined the term ‘gene’, that was referred to discrete determiners of inherited characteristics. According to the classical concept of gene introduced by Sutton in , genes have been defined as discrete particles that follow Mendelian rules of inheritance, occupy a definite locus in the chromosome and are responsible for the expression of specific phenotypic character. They show the following properties: • Number of genes in each organism is more than the number of chromosomes; hence several genes are located on the same chromosome. • The genes are arranged in a single linear order like beads on a string. • Each gene occupies a specific position called locus. • Genes may exist in several alternate forms called alleles. • Genes may undergo sudden change in positions and composition called mutations. • Genes are capable of self-duplication producing their own copies.