Publications (3)11.11 Total impact
-
Article: A test of morphological hypotheses for tribal and subtribal relationships of Aphidinae (Insecta: Hemiptera: Aphididae) using DNA sequences.
[show abstract] [hide abstract]
ABSTRACT: Aphidinae is the most diverse major lineage of aphids (Aphididae). Aphidinae currently dominate the temperate, northern-hemisphere fauna, but only since the late Tertiary, and few species are native to the southern hemisphere. The success of Aphidinae may be linked to the evolution of an unusual life cycle, host alternation. The classification and phylogeny of Aphidinae have been controversial; schemes based on morphology have been confounded by widespread homoplasy. Here we present the first phylogenetic study of higher-level Aphidinae relationships based on molecular data (elongation factor-1alpha, leucine tRNA, and cytochrome oxidase II sequences). Analyses supported the monophyly of Aphidini and its subtribes, Aphidina and Ropalosiphina, but revealed novel relationships concerning Pterocommatini and Macrosiphini, with the former nested within the latter tribe as the sister to Cavariella. Several relationships within Pterocommatini + Macrosiphini corresponded better with host-plant affiliations than with aphid classification. Overall, relationships found here challenge several traditional views of Aphidinae evolution: they suggest more than one origin of host alternation in the family, and they question the assumption that Aphidinae originated in the northern hemisphere.Molecular Phylogenetics and Evolution 03/2006; 38(2):316-29. · 3.61 Impact Factor -
Article: High levels of RNA editing in a vascular plant chloroplast genome: analysis of transcripts from the fern Adiantum capillus-veneris.
[show abstract] [hide abstract]
ABSTRACT: We sequenced transcripts from all putative genes for proteins, rRNAs, and a selection of gene-encoding tRNAs in the chloroplast genome of the fern Adiantum capillus-veneris. We detected 350 RNA editing sites when the cDNA sequence was compared to that of the genomic DNA. Of these sites, 10% were U-to-C edits and 90% were C-to-U edits. RNA editing created 19 new start codons, three new stop codons, and "repaired" 26 internal stop codons. Of the 332 editing sites that altered a codon, 26% were in the first codon position, 68% in the second, and 6% in the third. We also detected 21 silent edits, as well as 19 edits that were in untranslated regions, including introns and the anticodon of tRNA(Leu). The latter edit provided a tRNA that is not otherwise encoded in this genome and accounts for a heavily used leucine codon. The level of RNA editing in this fern is more than ten times that of any other vascular plant examined across an entire chloroplast genome. A previous study found even higher levels of editing in a hornwort (942 sites). This suggests that the relatively low levels of editing in seed plants (less than 0.05%) may not be typical for land plants, and that RNA editing may play a major role in chloroplast genome processing. Additionally, we found that 53 editing sites in A. capillus-veneris are homologous to editing sites in the hornwort, and some other land plants. This implies that a major component of RNA editing sites have been conserved for hundreds of millions of years.Gene 10/2004; 339:89-97. · 2.34 Impact Factor -
Article: Complete nucleotide sequence of the chloroplast genome from a leptosporangiate fern, Adiantum capillus-veneris L.
[show abstract] [hide abstract]
ABSTRACT: We determined the complete nucleotide sequence of the chloroplast genome of the leptosporangiate fern, Adiantum capillus-veneris L. (Pteridaceae). The circular genome is 150,568 bp, with a large single-copy region (LSC) of 82,282 bp, a small-single copy region (SSC) of 21,392 bp and inverted repeats (IR) of 23,447 bp each. We compared the sequence to other published chloroplast genomes to infer the location of putative genes. When the IR is considered only once, we assigned 118 genes, of which 85 encode proteins, 29 encode tRNAs and 4 encode rRNAs. Four protein-coding genes, all four rRNA genes and six tRNA genes occur in the IR. Most (57) putative protein-coding genes appear to start with an ATG codon, but we also detected five other possible start codons, some of which suggest tRNA editing. We also found 26 apparent stop codons in 18 putative genes, also suggestive of RNA editing. We found all but one of the tRNA genes necessary to encode the complete repertoire required for translation. The missing trnK gene appears to have been disrupted by a large inversion, relative to other published chloroplast genomes. We detected several structural rearrangements that may provide useful information for phylogenetic studies.DNA Research 05/2003; 10(2):59-65. · 5.16 Impact Factor
