Question

know the difference between dominant and recessive alleles

Explanation:

Dominant alleles are versions of a gene that will express their trait even if only one copy (from one parent) is present in the genotype. For example, in Mendelian genetics, if a pea plant has a dominant allele for purple flowers (let's say represented as \( P \)) and a recessive allele for white flowers (\( p \)), the genotype \( Pp \) will result in purple flowers because the dominant allele \( P \) is expressed. Recessive alleles, on the other hand, will only express their trait when two copies are present (homozygous recessive, like \( pp \) for white flowers in the pea plant example). This is because the dominant allele's expression masks the recessive one when both are present in a heterozygous (\( Pp \)) genotype.

Answer:

• Dominant alleles: Express their trait in heterozygous (\( Aa \)) or homozygous dominant (\( AA \)) genotypes. Only one dominant allele (from one parent) is enough to show the associated phenotype. For example, in human earlobe shape, the allele for free earlobes is dominant. If an individual has one or two copies of this dominant allele, they will have free earlobes.
• Recessive alleles: Express their trait only in homozygous recessive (\( aa \)) genotypes. Two copies of the recessive allele (one from each parent) are required for the recessive phenotype to be visible. For example, the allele for attached earlobes is recessive, so only individuals with two copies of this allele will have attached earlobes.