3H-uridine labelling patterns and chromosomal polymorphism inDrosophila subobscura: J and U chromosomes

The3H-uridine labelling patterns in J and U polytene chromosomes ofDrosophila subobscura were determined. The analysis was carried out in two developmental stages and in two strains proceeding from the same geographical origin whose genotypes were: Jst/Jst; U1+2/U1+2 and J1/J1; U1+2+8/U1+2+8 respectively. It was observed that the labelling pattern coincided very approximately with the puffing pattern in the same stages and chromosomal arrangements. Comparison of the3H-Uridine incorporation patterns between chromosomal arrangements showed light quantitative differences. These results are discussed in relation to the inversion effect.