Chromosomal basis of dosage compensation in Drosophila: II. The DNA replication patterns of the male X-chromosome in an autosome—X insertion in D. melanogaster

Abstract

SUMMARY: The functional morphology and the replication pattern of the male X-chromosome in an autosome-X insertion stock (T(1;3) 05) of Drosophila melanogaster have been examined. In larval salivary glands carrying this insertion neither the enlargement and pale staining of the single male X, nor the characteristic early completion of replication cycle, as revealed by ³H-TdR autoradiography is in any way changed. The normal properties of the inserted autosomal segment are also unaltered. The results appear to support a ‘piecemeal’ type of dosage compensation mechanism in Drosophila operating through the male.