To test whether gaps resulting from sequence alignment contain phylogenetic signal concordant with those of base substitutions, we analyzed the occurrence of indel mutations upon a well-resolved, substitution-based tree for three nuclear genes in bumble bees (Bombus, Apidae: Bombini). The regions analyzed were exon and intron sequences of long-wavelength rhodopsin (LW Rh), arginine kinase (ArgK), and elongation factor-1alpha (EF-1alpha) F2 copy genes. LW Rh intron had only a few uninformative gaps, ArgK intron had relatively long gaps that were easily aligned, and EF-1alpha intron had many short gaps, resulting in multiple optimal alignments. The unambiguously aligned gaps within ArgK intron sequences showed no homoplasy upon the substitution-based tree, and phylogenetic signals within ambiguously aligned regions of EF-1alpha intron were highly congruent with those of base substitutions. We further analyzed the contribution of gap characters to phylogenetic reconstruction by incorporating them in parsimony analysis. Inclusion of gap characters consistently improved support for nodes recovered by substitutions, and inclusion of ambiguously aligned regions of EF-1alpha intron resolved several additional nodes, most of which were apical on the phylogeny. We conclude that gaps are an exceptionally reliable source of phylogenetic information that can be used to corroborate and refine phylogenies hypothesized by base substitutions, at least at lower taxonomic levels. At present, full use of gaps in phylogenetic reconstruction is best achieved in parsimony analysis, pending development of well-justified and generally applicable methods for incorporating indels in explicitly model-based methods.
Larval development of nine populations of Aedes togoi (Theobald) collected from tropical to subarctic zones was studied under photoperiods of 16 h light (L) : 8 h dark (D) and 10 h L : 14 h D at 15 °C. Larvae that did not pupate within 60 days were regarded as diapausing. Larval diapause did not occur in all populations at 16 h L : 8 h D. At 10 h L : 14 h D, four populations from tropical and subtropical zones included no diapausing larvae, whereas 60–99% of individuals from five northern populations of Japan and Canada were diapausing. Adult size increased with latitude of original locality. The proportion of autogenous females among those developed at 16 h L : 8 h D and 15 °C decreased with original latitude, whereas that among females from nondiapausing larvae reared at 10 h L : 14 h D and 15 °C was consistently high throughout the latitudes. At 10 h L : 14 h D and 15 °C, larval developmental characters of F1 and F2 hybrids between Malaysian (no diapause) and Japanese (diapausing) populations were intermediate between the parental populations. Expression of autogeny of the hybrids was similar to that of the Malaysian strain. A Canadian population, which might have been introduced from Japan, showed developmental traits similar to those of two populations from temperate Japan.
This study reported the 15,435 bp-long complete mitochondrial genome of the relict Epiophlebia superstes (Odonata, Epiophlebiidae), an enigmatic dragonfly of the paraphyletic 'Anisozygoptera' possessing characteristics similar to members of both extant odonate suborders, the Zygoptera and the Anisoptera. This mitogenome comprises the common set of 37 genes and an A + T-rich control region, and has a gene arrangement identical to those of all available odonates. The genome contains three non-coding inter-genic spacers (s1-s3), which occurs in all of other known odonates, but it lacks the inter-genic spacer s5 typically found in the Anisoptera. This result suggests that E. superstes possesses a mitogenmic organization more closely related to that of the Zygoptera than that of the Anizoptera.
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