Spindle-Fiber Attachment End of the X-Chromosome of Drosophila virilis

Abstract

Virgin females heterozygous for, several sex-linked genes were subjected to X-ray treatment to increase the occurrence of primary non-disjunctional females. The percentage of homozygosis among these females for loci tested was as follows: sc (3.0) 26.7, c (23.5) 31.1, mt (68.5) 37.8, s (90.5) 22.2, sb (109.7) 28.9, ap (114.7) 26.3, rg (132.0) 17.7, bb (146) 4.2. The decrease of homozygosis toward the bobbed end of the chromosome indicates that the spindle-fiber attachment is located at that end.