Question

The phenotypic ratio of incomplete dominance is

• A. 2:1
• B. 1:2:1
• C. 1:1:1
• D. 1:1:2

Answer 1

The correct option is B 1:2:1

Incomplete dominance shows variation from Mendel's law of dominance. According to Mendel's law of dominance, when two contrasting genes are present in an individual, only one character will be expressed. The expressed gene will be called dominant and the suppressed gene will be called recessive. Whereas, according to the incomplete dominance, an intermediate character will also appear in F$${}_2$ generation in which one allele for a specific character is not completely expressed over its paired allele. The most common example is 4'O clock plant. When homozygous (RR) red flowered variety was crossed with homozygous (rr) white coloured variety, pink (Rr) flowered was obtained in the F${}_1$ generation, which was the intermediate between the red and white flowers. After the selfing ofF${}_1$ hybrids, the phenotypic and genotypic ratio was obtained as 1 (red): 2 (pink): 1 (white).