Question

(a) Explain a monohybrid cross taking seed coat colour as a trait in Pisum sativum. Work out the cross up to $F_2$ generation.
(b) State the laws of inheritance that can be derived from such a cross.
(c) How is the phenotypic ratio of $F_2$ generation different in a dihybrid cross?

Answer 1

a) The figure given above shows the F${}_1$ and F${}_2$ generations of a monohybrid cross for the seed coat colour trait in Pisum sativum.

b) This cross depicts the law of segregation which states that during the formation of gametes each pair of gametes segregates independently of the other pair of gametes.

c) For a monohybrid cross, the phenotypic F${}_2$ ratio is 1:2:1 while that for dihybrid cross is 9:3:3:1.