title: The evolution of multicellularity and early animal genomes.
abstract: Several independent molecular datasets, including complete mtDNA sequence, indicate that Choanozoa are most closely related to multicellular animals. There is still confusion concerning basal animal phylogeny, although recent data indicate that Placozoa are not degenerate cnidarians and hence (along with sponges) occupy a pivotal position. The transition in evolution from diploblast to bilaterian animals is becoming better understood, with gene expression data arguing that cnidarians have forerunners of the anteroposterior and dorsoventral body axes, and even a putative homologue of mesoderm. The homeobox and kinase gene families have been further analysed in basal animals, although more data are required to enable detailed comparison with Bilateria.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Nina M
authors.initials: NM
authors.lastname: Brooke
authors.forename: Peter W H
authors.initials: PW
authors.lastname: Holland
mesh_terms: D000818:Animals; D003063:Cnidaria / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D005801:Genes, Homeobox; D008648:Mesoderm; D010770:Phosphotransferases / Q000235:genetics; D010802:Phylogeny; D015398:Signal Transduction
chemical_list: D004272:DNA, Mitochondrial; D010770:Phosphotransferases