THE TORTOISE AND THE HARE - CHOOSING BETWEEN NONCODING PLASTOME AND NUCLEAR ADH SEQUENCES FOR PHYLOGENY RECONSTRUCTION IN A RECENTLY DIVERGED PLANT GROUP

Citation
Rl. Small et al., THE TORTOISE AND THE HARE - CHOOSING BETWEEN NONCODING PLASTOME AND NUCLEAR ADH SEQUENCES FOR PHYLOGENY RECONSTRUCTION IN A RECENTLY DIVERGED PLANT GROUP, American journal of botany, 85(9), 1998, pp. 1301-1315
Citations number
116
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Plant Sciences
Journal title
ISSN journal
0002-9122
Volume
85
Issue
9
Year of publication
1998
Pages
1301 - 1315
Database
ISI
SICI code
0002-9122(1998)85:9<1301:TTATH->2.0.ZU;2-6
Abstract
Phylogenetic resolution is often low within groups of recently diverge d taxa due to a paucity of phylogenetically informative characters. We tested the relative utility of seven noncoding cpDNA regions and a pa ir of homoeologous nuclear genes for resolving recent divergences, usi ng tetraploid cottons (Gossypium) as a model system. The five tetraplo id species of Gossypium are a monophyletic assemblage derived from an allopolyploidization event that probably occurred within the last 0.5- 2 million years. Previous analysis of cpDNA restriction site data prov ided only partial resolution within this clade despite a large number of enzymes employed. We sequenced three cpDNA introns (rpl16, rpoC1, n dhA) and four cpDNA spacers (accD-psaI, trnL-trnF, trnT-trnL, atpB-rbc L) for a total of over 7 kb of sequence per taxon, yet obtained only f our informative nucleotide substitutions (0.05%) resulting in incomple te phylogenetic resolution. In addition, we sequenced a 1.65-kb region of a homoeologous pair of nuclear-encoded alcohol dehydrogenase (Adh) genes. In contrast with the cpDNA sequence data, the Adh homoeologues yielded 25 informative characters (0.76%) and provided a robust and c ompletely resolved topology that is concordant with previous cladistic and phenetic analyses. The enhanced resolution obtained using the nuc lear genes reflects an approximately three- to sixfold increase in nuc leotide substitution rate relative to the plastome spacers and introns .