Understanding Genetics: Key Terms Explained

Today's discussion extends our previous conversation on DNA by diving into several essential genetic terms, focusing on understanding the concepts of alleles, dominance, recessiveness, homozygosity, heterozygosity, and the distinctions between genotype and phenotype.

Genes and Alleles

• A gene is a segment of DNA that encodes for a specific protein.
• Alleles are different versions of the same gene, accounting for the diversity in gene expression.
  • Everyone has two alleles of each gene, one from each parent, which can be the same (homozygous) or different (heterozygous).

Dominance and Recessiveness

• In cases where an individual has two different alleles (heterozygous), the dominant allele is expressed over the recessive one.
• For instance, a mouse heterozygous for fur color with one allele for purple fur (dominant) and one for green fur (recessive) will exhibit purple fur.

Homozygous vs. Heterozygous

• Homozygous: Having two identical alleles of a gene.
• Heterozygous: Having two different alleles of a gene.

Genotype and Phenotype

• Genotype refers to an individual's collection of alleles or the genetic makeup.
• Phenotype is the observable characteristics or traits that result from the genotype.
  • For example, both a heterozygous mouse and a homozygous dominant mouse for a purple fur allele will have a purple phenotype, though they have different genotypes.

In our next video, we'll explore genetic diagrams further, enhancing our understanding of how these concepts play out in real-life scenarios.