Paralogy and Orthology in the Malvaceae rpb2 Gene Family: Investigation of Gene Duplication in Hibiscus
Date
2004
Authors
Pfeil, Bernard
Brubaker, Curt L.
Craven, Lyn A.
Crisp, Michael
Journal Title
Journal ISSN
Volume Title
Publisher
Society for Molecular Biology Evolution
Abstract
A sample of the second largest subunit of low-copy nuclear RNA polymerase II (rpb2) sequences from Malvaceae subfamily Malvoideae suggests that rpb2 has been duplicated early in the subfamily's history. Hibiscus and related taxa possess two rpb2 genes, both of which produce congruent phylogenetic pattems that are largely concordant with cpDNA topologies. No evidence of functional divergence or disruption was found among duplicated copies, suggesting that long-term maintenance of duplicated copies of rpb2 is usual in this lineage. Therefore, this gene may be suitable for the potential diagnosis of relatively old polyploid events. One probable pseudogene was found in Radyera farragei and a single chimeric sequence was recovered from Howittia trilocularis, suggesting that the rpb2 locus is not as prone to evolutionary processes that can confound phylogenetic inferences based on nDNA sequences. The pattern of relationships among rpb2 sequences, coupled with chromosome number information and Southern hybridization data, suggests that an early polyploid event was not the cause of the duplication, despite independent evidence of paleopolyploidy in some members of Malvoideae. Rpb2 exons and introns together are suitable for phylogenetic analysis, producing well-resolved and well-supported results that were robust to model permutation and congruent with previous studies of subfamily Malvoideae using cpDNA characters.
Description
Keywords
Keywords: cell nucleus DNA; RNA polymerase II; amino acid sequence; angiosperm; article; chimera; chromosome number; DNA sequence; evolution; exon; gene; gene disruption; gene duplication; genetic variability; Hibiscus; Howittia trilocularis; intron; multigene fami Evolution; Gene duplication; Hibiscus; Low-copy nuclear DNA; Phylogenetics; RNA polymerase II
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Source
Molecular Biology and Evolution
Type
Journal article