Gene is a unit of inheritance, a piece of genetic material that determines the inheritance of a particular characteristic, or group of characteristics. Genes are carried by chromosomes in the cell nucleus and are arranged in a line along each chromosome. Every gene occupies a place or locus on the chromosome. Consequently, the word locus has become loosely interchangeable with the word gene.
The genetic material is deoxyribonucleic acid or DNA, a molecule that forms the backbone of the chromosomes. Because DNA in each chromosome is a single, long, thin continuous molecule the genes must be parts of that molecule and because DNA is a chain of minute sub units known as nucleotide bases, each gene includes many bases. Four different kinds of bases exist in the chain:
and their sequence in a gene determines its properties.[104]
- adenine (A)
- guanine (G)
- cytosine (C)
- thymine (T).
What is Gene?