Some notes on differential chromosome activity inDrosophila

In the lethal mutantltl ofDrosophila melanogaster, a characteristic pattern of puffs on the right arm of the third chromosome is described. This pattern includes anaerobiosis puffs in some of the lethal larvae. Puffing, and incorporation of radioactive uridine was observed even at advanced stages of disintegration. From the behaviour of the chromosomes it may be concluded that the internal milieu ofltl larvae differs from that of artificially (by ligating) over-aged wild type larvae as well as from that of the imago.