State and explain the law of dominance as proposed by Mendel.

Question

Answer the following questions:

A. State and explain the law of dominance as proposed by Mendel.

B. How would phenotypes of monohybrid F1 and F2 progeny showing incomplete dominance in Snapdragon and co-dominance in human blood group be different from Mendelian monohybrid F1 and F2 progeny ? Explain.

Answer 1

A.This law states that when two alternative forms of a trait or character (genes or alleles) are present in an organism, only one factor expresses itself in F1 progeny and is called dominant while the other that *** masked is called recessive. The characters are controlled by discrete units called factors. These factors occur in pairs.

B.

| | Mendelian monohybrid cross | Incomplete dominance | Co-dominance |
| F1 | All members resemble the parent with dominant trait. | All members do not resemble either of the two parents but show an intermediate trait. | Blood groups of all members resemble combination of dominant traits of both the parents |
| F2 | Both the parental traits reappear. | Both the parental traits and an intermediate trait appear. | Both the parental traits as well as the co-dominant trait appear. |