Cytogenetic analysis of theechinoid (ed), dumpy (dp)andclot (cl)region inDrosophila melanogaster

Abstract

SummaryThe chromosomal region surrounding theed, dpandclgenes has been studied cytogenetically (24–26 on 2L chromosome). It contains threeMinutesand a haplo-sterile function. For isolation of deficiencies and mutations these haplo-insufficient functions were covered by an insertional translocation of 24D4-25F2 into the X chromosome, or by tandem duplications. 112 lethal and visible mutations induced by EMS and X-rays have been localized by deficiency mapping to 20 subregions. They specify 42 loci in a 48 band interval consistent with the notion that most of the bands encode a single lethal function. Thedp, DTS, tkvand suppressor/enhancer loci for position-effect variegation were studied in detail. A dominant suppressor function was localized within the structural part of thedpcomplex. New non-conditional lethals have been isolated for theDTSlocus. Complementation analysis with the previously identified dominant heat-sensitive alleles places the site for heat sensitivity in the middle of the locus. Two haplo-abnormal enhancers of position-effect variegation were localized in the region 25F2–26A1. A triplo-abnormal suppressor function maps to 26B2–5; 26B9. The dose-dependent functions of these loci were studied by the use of deficiencies and duplications.