Chiasma distribution in asynaptic Locusta migratoria.

The formation of chiasmata in six full sib male partially asynaptic individuals of Locusta migratoria has been studied. The mean chiasma frequency per cell was 2.3 both at diplotene and metaphase I. Chiasmata tended to be distributed evenly among the bivalents. The frequency and distribution of the chiasmata in each type of bivalent (L, M, or S) depended on the level of asynapsis and on interference between the bivalents. Short bivalents were the most affected by interference, while M bivalents associated independently of L and S bivalent behaviour.