Phylogenetic Position Of The Spider Subfamily Coelotinae (Araneae) Inferred From Nuclear RDNA And 16S RDNA

This study discusses the classification of the spider subfamily Coelotinae based on the nuclear rDNA and 16S rDNA partial sequences, and studies the secondary structure of the 3' half of 16S rDNA.1 The application of the nuclear and mitochondrial genes in the spiders' phylogenetic studyThe nuclear and mitochondrial genes can provide accurate information because they continually accumulate variation in the course of evolution. The application of the nuclear and mitochondrial genes in the phylogenetic studies of spiders is reviewed.2 Review of the studies on families Agelenidae and AmaurobiidaeThe families Agelenidae and Amaurobiidae are two important families in Araneae. This chapter introduces briefly the research history, morphological characteristics, and biology of the two families.3 Phylogenetic position of the spider subfamily Coelotinae (Araneae) inferred from nuclear rDNA sequencesThe phylogenetic position of the subfamily Coelotinae, which belongs to Amaurobiidae currently but Agelenidae formerly, has remained controversial. The sequences of 28S and 18S rDNA fragments from six species of spiders, representing Ageleninae, Amaurobiinae, Coelotinae and Clubionidae, respectively, were obtained.The NJ, MP, ML and BI analyses generated identical topology. All trees from the 28S rDNA and 28S rDNA combined with 18S rDNA data derived from NJ, MP, ML and BI analyses support the Coelotinae as the sister group of the Ageleninae, and strongly support the Coelotinae + Ageleninae are the sister group of the Amaurobiinae. The topology in the trees inferred from 18S data is similar to those of 28S rDNA but with lower boostrap support. The results indicate that Coelotinae is probably a subfamily of the family Agelenidae.4 An analysis of the secondary structure of the hypervariable region of the 16S rDNA in spiders and its implications in phylogenetic reconstructionBased on the model given by Gutell et al. (1996), secondary structures were proposed for the hypervariable region of the 3' half of the 16S rDNA in the Tamgrinia tibetana (Amaurobiinae) and Asiacoelotes plancyi (Coelotinae), which were also analyzed by combining with the similar structures of four species in the Arachnids (Smith et al. 2003). The analysis revealed a trend of stem and loop reduction in araneae. The maximum parsimony analysis on 16S sequences for which the more variable regions were excluded, revealed that the relationship between Coelotinae and Ageleninae is closer than that between Coelotinae and Amaurobiinae. The result was also supported by the other analysis of the combined 18S^28S and morphological data. This study demonstrates the utility of secondary structure of rDNA in the phylogenetic reconstruction in spiders.