What is Genetics?
The science of Genetics defines and analyzes heredity, or constancy and change in the vast arrangement of physiologic functions that form the properties of organisms.
* The unit of heredity is the Gene :
- a segment on a DNA molecule.
- usually at a specific location (locus) on a chromosome or plasmid.
- characterized by its nucleotide sequence.
* Genotype:- alteration in the sequence of DNA within a gene or in the organization of genes .
* Phenotype:- the collective structural and physiologic properties of a cell or an organism, ex. eye color in a human or resistance to an antibiotic in a bacterium.