Compare and contrast the following terms:

homozygous and heterozygous

Key Concepts

Homozygous

Homozygous refers to an organism that has two identical alleles for a particular gene. This means that both inherited copies of the gene, one from each parent, are the same. For example, if an individual has two alleles for blue eyes (BB or bb), they are considered homozygous. Homozygosity can influence traits and can be important in breeding and genetic studies.

Heterozygous

Heterozygous describes an organism that has two different alleles for a specific gene. This means that one allele is inherited from one parent and a different allele from the other. For instance, an individual with one allele for brown eyes and one for blue eyes (Bb) is heterozygous. Heterozygosity can lead to a variety of phenotypes and is often associated with genetic diversity.

Genotype and Phenotype

Genotype refers to the genetic makeup of an organism, specifically the alleles present for a given gene, while phenotype is the observable expression of those genes, influenced by both genotype and environmental factors. Understanding the difference between homozygous and heterozygous genotypes is crucial, as it directly affects the phenotype, such as whether a trait is expressed dominantly or recessively.