Recombination in the proximal region of X/X. Y L or S Drosophila melanogaster females during temperature shocks in three stages of the life cycle

The specific brood patterns of recombination in the f ‐centromere region, the centromere marked by an attached B S Y L ‐arm, in the inbred lines of Drosophila metanogaster were further investigated according to effects of the brood from which the females were sampled (early broods‐pupal egg development; late broods‐egg development present in adults). The effect on recombination by another B S Y L or a y+Y S ‐arm was studied in six successive broods from females given temperature treatment in various stages of the life cycle. Temperature treatment enhanced the recombination in affected broods, resulting in fairly uniform level in the three series. In unaffected broods there were differences between the three attachments. The data indicate a diversity between females from early and late broods in the y+Y S series but not in the two B S Y L series. The consequences of temperature shock are discussed as well as the influence of different Y‐heterochromatin from Y S and Y L arms. In the light of the variation of recombination over broods the possible “centromere effect” is scrutinized.