Which of the following represents a trait that is not expressed in the presence of a dominant allele?

Master Mendelian concepts with our Mendelian Link Test. Access flashcards, key concepts, and multiple choice questions with insights. Get ahead in your studies!

The trait that is not expressed in the presence of a dominant allele is referred to as recessive. In Mendelian genetics, alleles can be categorized as dominant or recessive based on their expression. A dominant allele will mask the expression of a recessive allele when both are present in a heterozygous genotype. This means that for a recessive trait to be phenotypically observable, the individual must have two copies of the recessive allele, or be homozygous for that trait.

For instance, if we consider a gene involved in flower color where purple (P) is the dominant allele and white (p) is the recessive allele, a plant with the genotype Pp (one dominant and one recessive allele) will display purple flowers, while a plant with the genotype pp will show white flowers.

In contrast, dominant alleles express their traits regardless of the presence of other alleles, codominant alleles express both traits distinctly in a heterozygote, and polygenic traits involve multiple genes contributing to a single phenotype. Therefore, the correct identification of the recessive trait is essential for understanding Mendelian inheritance patterns.