Dating dispersal and radiation in the gymnosperm gnetum
Dating dispersal and radiation in the gymnosperm gnetum - Phone live random chat naughty
The insertion of the GATA motif in the (data not shown), further supporting the pseudogenization of this exon.
Concentration and quality of extracted DNAs were checked by 1.5% agarose gel electrophoresis with a Lambda/ sequences were designated as “gymnosperm-type,” whereas exon sequences homologous to angiosperm ones were designated “angiosperm-type.” Type-specific internal primers were then designed to prevent amplification of the other sequence type (Figs.4 and 5), and appropriate amounts (0.5–4 ng) of template DNA were added to the PCR master mixture following the manufacturer's protocol.Portions of the PCR products were run on an 1.5% agarose gel with a Lambda/RI size marker to verify the size and amount of the PCR products (Fig. Single band PCR products were purified with Qiagen PCR purification kits.Unlike group I introns, at least one of which appears to have been traded within flowering plants (16), group II introns in plants have been thought to be strictly vertically inherited (17–19), and the only known horizontal transfer of a group II intron in eukaryotes occurred in haptophytes, marine unicellular flagellates (20).intron 2 in 276 angiosperms and 17 gymnosperms representing all major lineages of seed plants had shown that the intron is widespread, but absent in seven unrelated angiosperms, non-Pinaceae conifers, and the Gnetales genus , gave a weak hybridization signal and multiple PCR products.Dots above the topmost sequence indicate the posttranscriptionally edited sites. Nonparametric bootstrap support was obtained by resampling the data 1,000 times with the same search options and model.
Parsimony analyses of full intron sequences using heuristic searching were run separately for each intron type.1), with domains I and V most crucial for the introns' enzymatic activity (12, 14) and ribozymic function (11, 12).Because of these characteristics and the presence of reverse transcriptase ORFs, they are believed to be the ancestors of spliceosomal introns and non-long-terminal repeat retroelements (13, 15). Among eukaryotic lineages, however, very few natural horizontal transfers have been reported, and none of them involve transfers across groups of seed plants. Group II introns are self-splicing RNAs that are typical components of contemporary organellar genomes in plants, algae, fungi, protists, and eubacteria (10, 12–14).They are characterized by a uniform structure of six major domains radiating from a central wheel (Fig.Mechanisms involved in yeast group II intron retrohoming/homing and coconversion (34, 35) are unlikely to apply to the present case of horizontal transfer because seed plant intron 2 (Fig.