Abstract:
:While it is widely accepted that most animals (Metazoa) do not have endogenous cellulases, relying instead on intestinal symbionts for cellulose digestion, the glycosyl hydrolase family 9 (GHF9) cellulases found in the genomes of termites, abalone, and sea squirts could be an exception. Using information from expressed sequence tags, we show that GHF9 genes (subgroup E2) are widespread in Metazoa because at least 11 classes in five phyla have expressed GHF9 cellulases. We also demonstrate that eukaryotic GHF9 gene families are ancient, forming distinct monophyletic groups in plants and animals. As several intron positions are also conserved between four metazoan phyla then, contrary to the still widespread belief that cellulases were horizontally transferred to animals relatively recently, GHF9 genes must derive from an ancient ancestor. We also found that sequences isolated from the same animal phylum tend to group together, and in some deuterostomes, GHF9 genes are characterized by substitutions in catalytically important sites. Several paralogous subfamilies of GHF9 can be identified in plants, and genes from primitive species tend to arise basally to angiosperm representatives. In contrast, GHF9 subgroup E2 genes are relatively rare in bacteria.
journal_name
Mol Biol Evoljournal_title
Molecular biology and evolutionauthors
Davison A,Blaxter Mdoi
10.1093/molbev/msi107subject
Has Abstractpub_date
2005-05-01 00:00:00pages
1273-84issue
5eissn
0737-4038issn
1537-1719pii
msi107journal_volume
22pub_type
杂志文章abstract::We report the genomic organization and deduced protein sequence of a cephalochordate member of the Otx homeobox gene family (AmphiOtx) and show its probable single-copy state in the genome. We also present molecular phylogenetic analysis indicating that there was single ancestral Otx gene in the first chordates which ...
journal_title:Molecular biology and evolution
pub_type: 杂志文章
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pub_type: 杂志文章
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更新日期:2012-03-01 00:00:00
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pub_type: 杂志文章
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更新日期:2001-09-01 00:00:00
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journal_title:Molecular biology and evolution
pub_type: 杂志文章
doi:10.1093/oxfordjournals.molbev.a025554
更新日期:1996-01-01 00:00:00
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pub_type: 杂志文章
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更新日期:2019-02-01 00:00:00
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pub_type: 杂志文章
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更新日期:1999-04-01 00:00:00
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pub_type: 杂志文章
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更新日期:2001-12-01 00:00:00
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