Question

Five Mark Questions :
(a) Explain Mendel's law of independent assortment by taking a suitable example.
(b) How did Morgan show the deviation in inheritance pattern in Drosophila with respect to this law?

Answer 1

(a) Law of independent assortment: If the inheritance of more than one pair of characters (two pairs or more) is studied simultaneously, the factors or genes for each pair of characters assort out independently of the other pairs. Mendel formulated this law from the results of a dihybrid cross. The law of independent assortment states that "when two parents differing from each other in two or ~ore pairs of contrasting. characters are crossed, then the inheritance of one pair of character is independent of the other pair of character". For example, when we cross a pure tall, red-flowered pea plant with a pure dwarf white-flowered pea plant, we get 9 tall red, 3 tall white, 3 dwarf red and 1 dwarf white plants in the F2. generation. A cross between two homozygous individuals differing in two characters is called dihybrid cross.

(b)When Morgan studied drosophila he found out that there are linked genes which are present on the chromosome and the inherited together so here the law of independent assortment is not seen.