Final answer:
Mendel's work on heredity suggested that traits are inherited as dominant and recessive pairs, forming the foundational principles of Mendelian genetics. However, this dominant-recessive relationship is sometimes expanded upon with concepts like incomplete dominance, where heterozygote phenotypes are intermediate.
Step-by-step explanation:
Mendel suggested heredity resulted in discrete units- a dominance-recessive relationship. This concept is a cornerstone in the field of genetics, where traits are passed down from parents to offspring in pairs of alleles, with one typically being dominant and the other recessive. However, Mendel's laws of inheritance were expanded to include patterns like incomplete dominance, where the phenotype of heterozygotes is somewhere in between the phenotypes of the two homozygotes.
For example, when Mendel crossed peas with contrasting traits, the recessive trait would reappear in a predictable 3:1 ratio, supporting the idea that traits are inherited in discrete units, rather than blending. In instances of incomplete dominance, such as the snapdragon flower coloration, the heterozygote offspring (CRCW) demonstrate an intermediate phenotype (pink flowers) as opposed to a dominant-recessive outcome.