PATTERNS OF PUFFING ACTIVITY AND CHROMOSOMAL POLYMORPHISM IN DROSOPHILA SUBOBSCURA. IV. EFFECT OF INVERSIONS ON GENE...

We have observed that, contrary to a common assumption, the puffing patterns manifest in the salivary chromosomes of Drosophila subobscura are modified by chromosomal inversions as well as by genic content. An inversion effect is apparent in the E and A chromosomes of five strains coming from four different natural populations. An effect due to the geographical location of the populations is also detected in the J and O chromosomes. The chromosomal and geographic effects are distinguishable but not contradictory. Indeed, a statistical test using the DK² coefficient of distance shows that, for a given chromosomal arrangement, strains of different geographic origin exhibit puffing patterns significantly different; these patterns are, however, more similar to each other than they are to those of strains carrying different chromosomal arrangements of the same chromosome.