2.26 Science Genetics

Phenotype

The observable physical or biochemical characteristics of an organism, determined by both genetic make-up and environmental influences.

Genotype

The genetic constitution of an individual, specifically the alleles present in the organism.

Homozygous Dominant

Having two identical dominant alleles for a trait (e.g., YY).

Homozygous Recessive

Having two identical recessive alleles for a trait (e.g., yy).

Heterozygous Dominant

Having one dominant allele and one recessive allele for a trait (e.g., Yy).

Punnett Square

A grid system used to predict the genotypes of offspring from a cross between two parents.

Mutation

A change in the DNA sequence that can lead to variations in traits.

Allele

One of two or more versions of a gene that determines a specific trait.

Genetic Trait

A characteristic that is inherited from parents to offspring, controlled by genes.

Dominant Allele

An allele that expresses its phenotype even when heterozygous with a recessive allele.

Recessive Allele

An allele that only expresses its phenotype when homozygous.