Higher ribosomal RNA substitution rates in Bacillariophyceae and Dasycladales than in Mollusca, Echinodermata, and Actinistia-Tetrapoda.
Molecular evolutionary rates within two protistan and three metazoan taxa were estimated using divergence times derived from fossil records. The results indicate that the small-subunit rRNA sequences within Dasycladales (Chlorophyta) and Bacillariophyceae evolved at a rate approximately two to three times faster than that estimated within Echinodermata, Mollusca, and Actinistia-Tetrapoda. It was concluded that this twofold discrepancy demonstrates actual taxonomic differences in the fixation rate of mutations in the small-subunit rRNA.
Sorhannus
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Department of Biology, Edinboro University of Pennsylvania 16444, USA. usorhanns@edinboro.edu
D000818:Animals; D005075:Biological Evolution; D000460:Chlorophyta / Q000235:genetics*; D017377:Diatoms / Q000235:genetics*; D004447:Echinodermata / Q000235:genetics*; D005399:Fishes / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D008974:Mollusca / Q000235:genetics*; D009154:Mutation; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics*; D012104:Reptiles / Q000235:genetics; D014714:Vertebrates / Q000235:genetics*
D012337:RNA, Ribosomal, 18S