Characterization of tetranucleotide microsatellite loci and development and validation of multiplex reactions for the study of right whale species (genus Eubalaena)

A North Atlantic right whale (Eubalaena glacialis) genomic library was developed and screened with a (GATA)₈ probe to identify tetranucleotide microsatellite loci. Sixteen characterized loci were polymorphic in North Atlantic and/or South Atlantic (Eubalaena australis) right whales, 12 being polymorphic in E. glacialis, and 15 in E. australis. Fourteen of these were combined with 21 other previously identified loci for a suite of 35 loci which can be used to increase resolution of genetic analyses of these species. Multiplex reactions were developed for genotyping samples at these loci, providing a method that is rapid, reliable and cost‐effective.     

Heme Proteins in Sulfide-oxidizing Bacteri/Mollusc Symbioses

SYNOPSIS. A number of bivalve mollusc species in the familiesVesicomyidae, Lucinidae and Solemyidae from sulfide-rich sedimentsharbor sulfide-oxidizing bacteria as intracellular symbiontsin gills. Cytoplasmic hemoglobin, relatively uncommon in symbiont-freegills, is a nearly constant feature in these symbiont-harboringbivalve gills and may function in the delivery of oxygen andsulfide to ensure symbiont autotrophy and host cell respiration.However, biochemical characteristics of isolated hemoglobinsfrom these species differ vastly. For example, within clamsof the same genus, gill hemoglobin concentrations vary frommicromolar to millimolar. Ligand reaction rate constants ofmultiple gill hemoglobins from a single species differ by threeorders of magnitude. Gill hemoglobins from congeners form differentderivatives in the presence of sulfide. Some hemoglobins reactavidly with hydrogen sulfide while others appear refractory.This assortment of characteristics suggests that the role ofhemoglobin in each symbiotic association cannot be generalized.     

Phylogenetic relationships of colubroid snakes based on mitochondrial DNA sequences

We used a 694 bp length of the mitochondrial ND4 gene from 40 genera to infer phylogenetic relationships among colubroid snakes. The goals of this study were to identify conserved subsets of ND4 sequence data that could be used to address (1) which nominal higher-level colubroid taxa are monophyletic, and (2) the relationships among the monophyletic lineages identified. Use of transversions only proved the most reliable and efficient means of retrieving colubroid relationships. Transversion parsimony and neighbour-joining analyses identify similar monophyletic higher-level taxa, but relationships among these lineages differ considerably between the two analyses. These differences were affected by the inclusion/exclusion of (1) transitions, (2) autapomorphies, and (3) the boid outgroups. Saturation effects among the transitions, uninformativeness of autapomorphies for clustering taxa, and long-branch and base-compositional problems among the boids lead us to regard the tree resulting from transversion parsimony analysis rooted with Acrochordus as the best current estimate of colubroid phylogenetic relationships. However, several aspects of this proposed phylogeny need further testing (e.g. the apparent diphyly of Natricinae is especially controversial). Relationships retrieved using all colubroid taxa are not obtained when sparsely or unevenly sampled experimental subsets of taxa are used instead, suggesting that long-branch problems can severely compromise elucidation of colubroid relationships if limited taxonomic sampling strategies are followed. We discuss the importance of this finding for previous molecular attempts to assess colubroid relationships. Our analyses confirm the historical validity of several nominal colubroid families and subfamilies, establish polyphyly of a few, but generally fail to resolve relationships among the monophyletic taxa we identify. More conservative character information will be required to confidently resolve the last issue.