Definitions: Gene, Allele, Dominant Recessive, Phenotype and Genotype

[Anandi]

Distinguish clearly between the terms
I.   Gene and allele
II.   Dominant and recessive
III.   Phenotype and genotype

A gene is hereditary unit that is situated at a definite site in a chromosome and transmit a character a trait from the parent to the offsprings. Chemically genes are made up to DNA.

Alleles are contrasting forms of a gene situated on comparable regions of homologous chromosomes .The gene for height exist in two different allelic forms: an allele for tallness and an allele for dwarfness.

Dominant-one which produces its effect whether it is homozygous a heterozygous. A dominant gene is represented by a capital letter.
Recessive one which produces its effect only when it is homozygous and it is represented by a small letter.

Phenotype: the expressed trait in an individual
Genotype: the genetic make-up on constitution of n I