Greg S. Spicer

Molecular evolution among someDrosophila species groups as indicated by two-dimensional electrophoresis

SummaryThe evolutionary and phylogenetic relationships of sevenDrosophila species groups (represented byD. melanogaster, D. mulleri, D. mercatorum, D. robusta, D. virilis, D. immigrans, D. funebris, andD. melanica) were investigated by the use of two-dimensional electrophoresis. The resulting phylogeny is congruent with the current views of evolution among these groups based on morphological characters and immunological distances. Previous studies indicated that the ability of one-dimensional electrophoresis to resolve relationships between distantly related taxa extended to about the Miocene [25 million years (Myr) ago], but the present study demonstrates that two-dimensional electrophoresis is a useful indicator of phylogeny even back to the Paleocene (65 Myr ago). In addition, two-dimensional electrophoresis is shown to be a useful technique for detecting slowly evolving structural proteins such as actins and tropomyosins.

A phylogenetic analysis of the emberizid sparrows based on three mitochondrial genes.

Previous molecular phylogenetic studies have examined the taxonomic relationships among a number of typical emberizid sparrow genera. To help clarify these relationships, we sequenced a 1673 base pair fragment for the complete sequence of three mitochondrial genes: adenosine triphosphatase (Atp8 and Atp6) and cytochrome oxidase subunit III (COIII) for 38 sparrow species, along with Passerina amoena (Cardinalidae) and Piranga ludoviciana (Thraupidae) which were selected as the outgroups. Our analysis confirms the monophyly of traditional genera such as Junco, Melospiza, and Zonotrichia. Although Calcarius and Plectrophenax are often thought to be putative emberizids, all our analyses placed these genera basal to all other sparrows examined. As observed with Calcarius, Spizella did not form a monophyletic group, with S. arborea being the sister-taxon to Passerella iliaca. Our analyses also suggest that Aimophila ruficeps is probably more closely related to the brown towhees (Pipilo aberti, P. crissalis, and P. fuscus) than its putative congeners. The genus Ammodramus was also not monophyletic, since it appears that Passerculus sandwichensis is more closely related to A. henslowii and A. leconteii then either one is related to its congener A. savannarum. Finally, our analyses exhibited other unsuspected associations, such as the sister-taxon relationships between Amphispiza bilineata and the Chondestes grammacus/Calamospiza melanocorys clade, and Amphispiza belli and Pooecetes gramineus.

Phylogeny of the Dragonfly and Damselfly Order Odonata as Inferred by Mitochondrial 12S Ribosomal RNA Sequences

Abstract The phylogenetic relationships among members of the Odonates were inferred from mitochondrial DNA 12S ribosomal RNA sequence data. These data show support for a monophyletic Anisoptera suborder, which are consistent with previous phylogenetic work performed on the group. However, the Zygoptera are paraphyletic based on mitochondrial DNA evidence. In particular, the family Lestidae appears more closely related to the Anisoptera then the Zygoptera.

Prevalence and host-parasite list of some nasal mites from birds (Acarina: Rhinonyssidae, Speleognathidae)

A survey of nasal mites, primarily from birds in Texas, was reported and comparisons with the other major studies were made. Of 103 host species examined, 40 were parasitized, and of 502 individual birds examined, 87 were parasitized (17% prevalence). It was shown that the prevalence of infection was significantly dependent on the bird taxa examined, which indicates that the evolution of the hosts has affected the nasal mites ability to parasitize their avian hosts. It was also shown that the prevalence of rhinonyssid nasal mites in their hosts seems to differ significantly between geographic regions.

Nasal mites from birds of a Guatemalan cloud forest (Acarina: rhinonyssidae)

A survey of the nasal mites from Guatemalan cloud forest birds is reported. Seventy-eight birds, representing 10 families and 18 species, were examined. Prevalance of infection was 24%. Two new species are described: Sternostoma darlingi from Mitrephanes phaeocercus (Tyrannidae) and S. pencei from Empidonax flavescens (Tyrannidae). New host records are reported for S. pirangae from Chlorospingus ophthalmicus (Thraupidae), S. hutsoni from Catharus dryas (Turdidae), Ptilonyssus sairae from Chlorospingus opthalmicus (Thraupidae) and Myioborus miniatus (Parulidae), P. euroturdi from Catharus dryas (Turdidae), P. tyrannus from Empidonax flavescens and Mitrephanes phaeocercus (both Tyrannidae), and Tinaminyssus ixoreus from Catharus dryas (Turdidae). The subspecies Ptilonyssus euroturdi mimicola Fain and Hyland is synonymized with the nominate subspecies. Data are presented to suggest that the Rhinonyssidae may be a polyphyletic assemblage.

The separation of whale myoglobins with two-dimensional electrophoresis

Five myoglobins (sperm whale, Sei whale, Hubbs beaked whale, pilot whale, and Amazon River dolphin) were examined using two-dimensional electrophoresis. Previous reports indicated that none of these proteins could be separated by using denaturing (in the presence of 8–9 M urea) isoelectric focusing. This result is confirmed in the present study. However, all the proteins could be separated by using denaturing nonequilibriumpH-gradient electrophoresis in the first dimension. Additionally, all the myoglobins have characteristic mobilities in the second dimension (sodium dodecyl sulfate), but these mobilities do not correspond to the molecular weights of the proteins. We conclude that two-dimensional electrophoresis can be more sensitive to differences in primary protein structure than previous studies indicate and that the assessment seems to be incorrect that this technique can separate only proteins that have a unit charge difference.