An allele that masks the expression of another allele in a heterozygous genotype is known as a dominant allele. In contrast, the allele that is masked is called a recessive allele. Dominant alleles are typically represented by uppercase letters (e.g., A), while recessive alleles are represented by lowercase letters (e.g., a). In a heterozygous genotype (e.g., Aa), the dominant allele will determine the observable phenotype, while the recessive allele will remain unexpressed until it is paired with another copy of the same recessive allele (e.g., aa).
Alleles: The Building Blocks of Traits
Picture this: you inherit a gene from your mom and another from your dad. These genes are like blueprints for your body, but they’re not always identical. They can come in different alleles, which are like alternative versions of the same gene.
Imagine your hair color gene. You could inherit an allele for brown hair from your mom and an allele for blonde hair from your dad. These alleles occupy the same spot on your chromosomes, but they have different nucleotide sequences, like different letters in a word.
These different alleles can result in different traits, like brunette or blonde locks. So, your hair color phenotype (what you can see) is determined by the combination of alleles you inherit (your genotype).
It’s like a genetic game of mix-and-match! Your alleles shuffle around, creating a unique genotype for each person. And depending on which alleles you inherit, you end up with different traits that make you the special snowflake you are.
