Gene, DNA & Inheritance

Gregor Mendel was the first to discover that inherited traits are determined by units of material which are passed, usually unaltered down the generations. These units of inheritance were later called genes.

Genes are essentially composed of DNA (DeoxyriboNucleicAcid). DNA
is in turn made of deoxyribonucleic acids which are polynuleotides, that is, nuclotides linked by phosphodies- ter bonds between the nucleotide deoxyribose sugars.

In DNA, there are four nucleotides that differ essentially in their constituent bases. Specific base pairs are formed between Adenine and Thymine (AT) and between Guanine and Cytosine (GC). The bases are aromatic and planar and form hydrogen bonds in the plane of the rings. This standard base pair can only be formed if the polynucleotide chains are running in opposite directions.

Base pairs, formed as discribed above, tend to interact with each other thereby forming two complementry nucleotide chains.

Thus, known DNA molecules consist of two totally comple- mentary chains in the form of a double helix.

Back