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Paxβ: a novel family of lophotrochozoan Pax genes
Author(s) -
Schmerer Matthew,
Savage Robert M.,
Shankland Marty
Publication year - 2009
Publication title -
evolution and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 78
eISSN - 1525-142X
pISSN - 1520-541X
DOI - 10.1111/j.1525-142x.2009.00376.x
Subject(s) - biology , gene , gene duplication , genetics , gene family , zygote , mesoderm , sister group , functional divergence , intron , evolutionary biology , phylogenetic tree , genome , embryogenesis , embryonic stem cell , clade
SUMMARY Paxβ is a novel gene family restricted to the bilaterian superphylum Lophotrochozoa. The Paxβ paired domain is highly diverged from other bilaterian Pax genes, and we were unable to identify an unambiguous sister‐group by phylogenetic sequence analysis. However, conservation of a paired domain intron suggests that the Paxβ genes arose by duplication and divergence from an ancestral Pax2/5/8 gene. We have identified Paxβ genes in annelids, molluscs, a nemertean, a brachiopod, and a flatworm, indicating that the founding gene duplication occurred before the separation of those taxa and therefore early in the lophotrochozoan radiation. The leech Helobdella has two genes in this family, Hau‐Pax β 1 and ‐ Pax β 2 , which are expressed during embryonic development. Hau‐Pax β 1 is present in the zygote as a localized maternal transcript, and both show dynamic patterns of apparently zygotic expression during later stages. These later expression patterns differ significantly, but both genes are expressed broadly in the mesoderm and also in the central nervous system during organogenesis.