Related Experiment Video
Updated: Aug 17, 2026

Using Whole Mount in situ Hybridization to Link Molecular and Organismal Biology
Published on: March 31, 2011
Class 3 Hox genes in insects and the origin of zen
F Falciani1, B Hausdorf, R Schröder
1Department of Genetics, Wellcome/Cancer Research Campaign Institute, Cambridge, England.
Abstract:
We have cloned, from a beetle and a locust, genes that are homologous to the class 3 Hox genes of vertebrates. Outside the homeobox they share sequence motifs with the Drosophila zerknüllt (zen) and z2 genes, and like zen, are expressed only in extraembryonic membranes. We conclude that the zen genes of Drosophila derive from a Hox class 3 sequence that formed part of the common ancestral Hox cluster, but that in insects this (Hox) gene has lost its role in patterning the anterio-posterior axis of the embryo, and acquired a new function. In the lineage leading to Drosophila, the zen genes have diverged particularly rapidly.
Related Concept Videos
Osmoregulation in Insects
Position-effect Variegation
Cis-regulatory Sequences
The Ratio of X Chromosome to Autosomes
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Zygotic Development And Stem Cell Formation

