For some of the traits Mendel studied, alleles were incompletely dominant or codominant. True false
The correct answer and explanation is:
True
Mendel’s classic experiments on inheritance primarily involved traits with complete dominance, where one allele completely masks the effect of another. However, some traits exhibit incomplete dominance or codominance, which differ from this simple dominant-recessive pattern.
In incomplete dominance, neither allele is completely dominant over the other. As a result, the heterozygous genotype produces an intermediate phenotype, a blend of both alleles. A common example of incomplete dominance is seen in the flower color of snapdragons. If a red-flowered plant (RR) is crossed with a white-flowered plant (WW), the offspring (RW) will have pink flowers, which is a blend of the red and white colors.
Codominance, on the other hand, occurs when both alleles contribute equally to the phenotype, with both traits being fully expressed in the heterozygous individual. A well-known example of codominance is seen in human blood types. In this case, the A and B alleles are codominant, so a person inheriting an A allele from one parent and a B allele from the other will have type AB blood, where both the A and B antigens are expressed on the surface of red blood cells.
These examples demonstrate that inheritance patterns are not always as straightforward as Mendel’s original experiments suggested. Although Mendel’s laws of inheritance laid the foundation for understanding genetics, the discovery of incomplete dominance and codominance has expanded our understanding of genetic variation and the complexity of inheritance patterns. Therefore, while Mendel studied traits with simple dominance, his work paved the way for further discoveries in genetics.