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Trends Genet. 2009 Sep;25(9):404-13. doi: 10.1016/j.tig.2009.07.006. Epub 2009 Aug 27.

More than just orphans: are taxonomically-restricted genes important in evolution?

Author information

1
Zoological Institute, Christian-Albrechts-University Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.

Abstract

Comparative genome analyses indicate that every taxonomic group so far studied contains 10-20% of genes that lack recognizable homologs in other species. Do such 'orphan' or 'taxonomically-restricted' genes comprise spurious, non-functional ORFs, or does their presence reflect important evolutionary processes? Recent studies in basal metazoans such as Nematostella, Acropora and Hydra have shed light on the function of these genes, and now indicate that they are involved in important species-specific adaptive processes. Here we focus on evidence from Hydra suggesting that taxonomically-restricted genes play a role in the creation of phylum-specific novelties such as cnidocytes, in the generation of morphological diversity, and in the innate defence system. We propose that taxon-specific genes drive morphological specification, enabling organisms to adapt to changing conditions.

PMID:
19716618
DOI:
10.1016/j.tig.2009.07.006
[Indexed for MEDLINE]

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