Homeotic gene
Homeotic genes or homeotic genes (from the Greek homeosis = change, transformation) are genes in developmental biology that are responsible for the identity of segments. Mutations within these genes can lead to a complete or partial transformation of organ structures or body segments. These genes were discovered on the basis of the antennapedia mutation of a homeotic gene in the model organism of the “black-bellied” fruit fly ( Drosophila melanogaster ), in which legs grow on the fly's head instead of antennae. These are genes that encode regulatory proteins. Their task is evidently to control cell differentiation and morphogenesis of multicellular organisms.
Knowledge of these genes led to the discovery of the homeobox . It is a characteristic sequence of homeotic genes. The homeoboxes code in the cells for delimitable specific protein areas or protein domains ( homeodomains ). They usually consist of 60 amino acids and have a DNA binding domain. Due to their specific attachment to DNA, entire gene areas can be shut down.
Homeotic genes are evolutionarily highly conserved and can therefore be found not only in insects, but also in vertebrates (and humans). They have also been proven in mushrooms . In plants, there are comparable regulatory gene areas ( MADS box ). From today's point of view, these homeoboxes represent a basic regulatory mechanism for individual development that emerged early in evolution .
Individual evidence
- ^ A b R. Wehner, W. Gehring: Zoologie. Thieme Verlag Stuttgart, 23rd edition 1995, p. 803.
- ↑ Purves, Sadava et al. : Biology. Spektrum Verlag 2006, p. 486f.
- ↑ E. Weiler, L. Nover: General and molecular botany. Thieme Verlag, Stuttgart 2008, p. 715ff.
- ↑ W. Gehring: The molecular basis of development. In: Development and Genes. Spektrum Verlag 1998.