PATTERNS OF PUFFING ACTIVITY IN SALIVARY GLAND CHROMOSOMES OF DROSOPHILA .2. X-CHROMOSOME PUFFING PATTERNS OF D MELANOGASTER AND D SIMULANS

Salivary gland X chromosome puffing patterns are described for the Oregon stock of Drosophila melanogaster and for the Berkeley stock of D. simulans. In D. melanogaster regular phase specific puffing was recorded at 21 loci in the third larval instar and subsequent prepupal stage. A comparison of the X chromosome puffing patterns of male and female larvae failed to show any qualitative differences although in the males a group of puffs were active for a longer time during development than in females. The X chromosome puffing patterns of D. simulans are similar to those described for D. melanogaster although two puffs (4F 1-4 and 7B 1-3) were active in D. simulans but not in D. melanogaster. The sex differences in puffing observed in D. melanogaster were also observed in D. simulans. © 1969 Springer-Verlag.