Review
of some key genetic terminology
Gene:
The hereditary determinant.Carrier of Genetic information
Allele:
Forms of a particular
gene.
Examples:
R or r; D or d; Y or y (Round or wrinked, Tall or dwarf, Yellow or green)
Genotype:
Genetic constitution
of an organism or cell.
Can refer
to the entire genetic complement or to only the specific alleles in question.
Examples:
RR; Rr; rr
Homozygous:
A genotype
in which pairs of alleles are the same.
Examples:
RR or rr, YY or yy
Heterozygous:
A genotype
in which pairs of alleles are different.
Examples:
Rr, Yy
Phenotype:
Observable
properties of an organism.
Usually
with reference to the trait of interest.
Note: phenotype
does not necessarily reveal the genotype.
Example:
Round = RR or Rr. Usually the genotype does reveal the phenotype,
although there are exceptions.