Q.Bring out the inheritance of chloroplast gene with an example.

Step 1. Chloroplast inheritance is demonstrated in the four o'clock plant (Mirabilis jalapa), which occurs in two variegated-leaf forms - dark-green-leaved plants and pale-green-leaved plants.

Step 2. If the trait followed ordinary Mendelian (nuclear) inheritance, a reciprocal cross pair should give identical F1 results regardless of which parent supplies the pollen; but when dark-green pollen fertilises a pale-green plant, the F1 is dark-green, while in the reciprocal cross, pale-green pollen fertilising a dark-green plant gives a pale-green F1.

Step 3. In both crosses, the F1 offspring specifically match whichever parent served as the female (egg-donating) parent, not the male pollen parent - the diagnostic sign that the trait is not carried on a nuclear chromosome at all. …

Use the Mirabilis reciprocal-cross result (F1 matches the female parent) to demonstr …

• Describing the cross result without connecting it to WHY it is maternal (the egg's cytoplasm contribution vs. the pollen's lack of it). …