GENETICS VOCABULARY

 

GENE – A location on a chromosome that codes for a general trait (protein).  Example:  Plant Height Gene

 

ALLELES – Different forms of the same gene.  Examples:  A and a.

 

PHENOTYPE – The physical appearance of an organism due to its genetics.  Examples: Tall and Dwarf.  PHENOTYPIC RATIO: 3:1 Tall:Dwarf

 

GENOTYPE – The genetic combination of alleles in an individual.  GENOTYPIC RATIO: 1:2:1  AA: Aa: aa.  3 Basic Genotypes:

1. HOMOZYGOUS DOMINANT – both alleles are dominant – AA

2. HOMOZYGOUS RECESSIVE – both alleles are recessive – aa

3. HETEROZYGOUS – the alleles are different from one another - Aa