Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 1995 Aug 1;92(16):7227-31.
doi: 10.1073/pnas.92.16.7227.

Identification of planarian homeobox sequences indicates the antiquity of most Hox/homeotic gene subclasses

G Balavoine  1 , M J Telford
Affiliations
Comparative Study

Identification of planarian homeobox sequences indicates the antiquity of most Hox/homeotic gene subclasses

G Balavoine et al. Proc Natl Acad Sci U S A. .

Abstract

The homeotic gene complex (HOM-C) is a cluster of genes involved in the anteroposterior axial patterning of animal embryos. It is composed of homeobox genes belonging to the Hox/HOM superclass. Originally discovered in Drosophila, Hox/HOM genes have been identified in organisms as distantly related as arthropods, vertebrates, nematodes, and cnidarians. Data obtained in parallel from the organization of the complex, the domains of gene expression during embryogenesis, and phylogenetic relationships allow the subdivision of the Hox/HOM superclass into five classes (lab, pb/Hox3, Dfd, Antp, and Abd-B) that appeared early during metazoan evolution. We describe a search for homologues of these genes in platyhelminths, triploblast metazoans emerging as an outgroup to the great coelomate ensemble. A degenerate PCR screening for Hox/HOM homeoboxes in three species of triclad planarians has revealed 10 types of Antennapedia-like genes. The homeobox-containing sequences of these PCR fragments allowed the amplification of the homeobox-coding exons for five of these genes in the species Polycelis nigra. A phylogenetic analysis shows that two genes are clear orthologues of Drosophila labial, four others are members of a Dfd/Antp superclass, and a seventh gene, although more difficult to classify with certainty, may be related to the pb/Hox3 class. Together with previously identified Hox/HOM genes in other flatworms, our analyses demonstrate the existence of an elaborate family of Hox/HOM genes in the ancestor of all triploblast animals.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Bioessays. 1994 Nov;16(11):801-8 - PubMed
    1. Mol Biol Evol. 1987 Jul;4(4):406-25 - PubMed
    1. Mol Phylogenet Evol. 1993 Sep;2(3):185-92 - PubMed
    1. J Exp Zool. 1991 Dec;260(3):413-6 - PubMed
    1. FEBS Lett. 1993 Nov 1;333(3):271-4 - PubMed

Publication types