Dominance and Phenotype Ratios in Genetics

What is the likely ratio resulting from incomplete dominance in a monohybrid cross?

How does incomplete dominance affect the phenotypes of offspring in genetic crosses?

Answer:

In incomplete dominance, a likely ratio resulting from a monohybrid cross is typically 1:2:1. This ratio demonstrates a blend of the parents' phenotypes, where the offspring exhibit an intermediate or mixed phenotype. When two individuals with different homozygous genotypes for a particular trait are crossed, the resulting phenotypic ratio among their offspring is commonly 1:2:1.

In genetics, incomplete dominance refers to a pattern of inheritance where neither allele is completely dominant over the other, resulting in a blend of phenotypes in heterozygous individuals. This phenomenon contrasts with complete dominance, where one allele completely masks the expression of the other. When a monohybrid cross occurs between two individuals with different homozygous genotypes for a particular trait under incomplete dominance, the resulting offspring typically exhibit a 1:2:1 phenotypic ratio. This means that one-fourth of the offspring will display one homozygous phenotype, two-fourths (or half) will display an intermediate or blended phenotype, and the remaining one-fourth will display the other homozygous phenotype. For example, if a flower with red petals (RR) is crossed with a flower with white petals (WW) under incomplete dominance, the resulting offspring will have pink petals (RW). Subsequent crosses between these pink-flowered offspring will yield a ratio of red (RR), pink (RW), and white (WW) flowers in a 1:2:1 ratio. Understanding the implications of incomplete dominance in genetic crosses is crucial for predicting and interpreting phenotypic outcomes. This phenomenon showcases the complexity of genetic inheritance and highlights the diversity of traits that can arise from genetic combinations.