Molecular Analysis of Kruppel, a Segmentation Gene of Drosophila melanogaster

Mutations of the three "gap" genes, a class of segmentation genes of Drosophila melanogaster, cause contiguous groups of adjacent segments of the embryo to fail to develop (Nüsslein-Volhard and Wieschaus 1980). In hunchback, the thoracic segments are deleted, whereas in knirps only two rather than eight denticle bands are formed in the abdomen of the embryo (Nüsslein-Volhard and Wieschaus 1980). The gap in the segmentation pattern of homozygous Krüppel (Kr) embryos overlaps the borders seen in the segmentation pattern of the other two gap mutants (Nüsslein-Volhard and Wieschaus 1980; Wieschaus et al. 1984).