Phylogenetics and evolution of a circumarctic species complex (Cladocera Daphnia
pulex)
Biological Journal of the Linnean Society Vol. 65, No. 3, November 1, 1998. pp. 347-365
J K COLBOURNE, , T J CREASE, L J WEIDER, P D. N HEBERT, F DUFRESNE,
A HOBÆK.
The evolutionary history of
is still relatively unknown.
However, studies of the microcrustacean Daphnia have revealed interesting patterns; the daphniids that dominate ponds and lakes in the northern hemisphere may have recent origins, likely associated with the glacial advances and retreats during the Pleistocene.
Moreover, they form species complexes that actively engage in hybridization and introgression. The present study examines the phylogenetic relationships among circumarctic members of the Daphnia pulex complex, through the analysis of sequence diversity in 498 nt of the ND5 mitochondrial gene. Our results suggest that the complex is composed of three major clades, two of which are subdivided into at least eight different lineages. Clearly, species in the complex show genetic discontinuity. Many lineages originated during the Pleistocene, but at least three lineages diverged during the
Pliocene. Two taxa (D. pulex, D. pulicaria), thought to be broadly distributed in the northern hemisphere, are shown to be endemic to single continents. In general, the diversification of the pulex complex is characterized by rapidly dispersed lineages spanning enormous distances and also by endemism in temperate areas. Gene flow among lineages from the temperate region of different continents are restricted to rare inter-continental migrations across a polar bridge followed by convergent morphological evolution.
Phylogenetic Relationships of North American Field Crickets Inferred from
Mitochondrial DNA Data
Yuan Huang, Guillermo Ortí, Marie Sutherlin, Amy Duhachek, and Anthony Zera
Molecular Phylogenetics and Evolution. Vol. 17, No. 1, October 2000. pp. 48-57
A well-supported molecular phylogeny for North American Gryllus species based on a combined data set of mitochondrial (mt) DNA is presented. A total of 26 individuals representing 13 populations of 11 species of the genus Gryllus and 4 individuals of two outgroup species, Teleogryllus oceanicus and Acheta domestica, were sampled in this study. The complete cytochrome b gene (1036 bp) and a 500-bp fragment of the 16S rRNA gene were sequenced for each individual. Since results from separate analyses of the cytochrome b and 16S data sets, as well as a previously published mtDNA restrictionsite data set, were not conflicting, all data were combined for phylogenetic analyses. The clade of European Gryllus was early separated from the North American clade. The amount of sequence divergence between these clades was significantly greater than within the clades, suggesting a basal drift-vicariant event in the genus. This is the first phylogenetic analysis of North American Gryllus that includes western species. Four well-supported groups were identified but their relationships showed no clear east-west structure. Our phylogeny supports the recent reassignment of G. integer Scudder 1901

from Texas to G. texensis Cade and Otte 2000. The evolution of cricket song and life cycle is discussed using the new phylogenetic framework.
Zimmitti SJ.
Individual variation in morphological, physiological, and biochemical features associated with
(Pseudacris crucifer).
Physiol Biochem Zool. 1999 Nov-Dec;72(6):666-76.
Phylogeography of Mitochondrial DNA Variation in Brown Bears and Polar Bears
Gerald F. Shields, Deborah Adams, Gerald Garner, Martine Labelle, Jacy Pietsch,
Malcolm Ramsay, Charles Schwartz, Kimberly Titus, Scott Williamson
Molecular Phylogenetics and Evolution, Vol. 15, No. 2, May 2000, pp. 319-326 (doi:
10.1006/mpev.1999.0730)
We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic
Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of
Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.
Phylogenetic systematics and biogeography of the poison frogs: evidence from mitochondrial
DNA sequences
Biological Journal of the Linnean Society Vol. 70, No. 3, July 1, 2000

MARK CLOUGH, KYLE SUMMERS
Regions of the mitochondrial genome were sequenced and analysed in representative species of poison frogs, in order to investigate phylogenetic relationships within the family Dendrobatidae. Mitochondrial DNA (mtDNA) fragments from three gene regions; cytochrome b, 16S ribosomal RNA (rRNA), and 12S rRNA, provided 1198 base pairs of
DNA sequence and 589 informative sites. Phylogenetic analysis using parsimony was used to infer the evolutionary relationships among the species in the survey. Our analysis supported previous partitions of species into the genera Epipedobates, Phyllobates and
Dendrobates, with two exceptions Epipedobates (Allobates) femoralis was placed outside the clade containing the other toxic dendrobatids, and Minyobates minutus was placed within the genus Dendrobates. Genetic distances estimated between all pairs of taxa using the Kimura 2-parameter model indicated substantial genetic divergence between species, particularly those found in Amazonia. Time of divergence estimates were highly variable depending on gene region, but even the lowest estimates were inconsistent with the
Pleistocene Refugia hypothesis
Mitochondrial Phylogeography of Moose (Alces alces): Late Pleistocene Divergence and Population Expansion
“Molecular Phylogenetics and Evolution”, Vol. 22, No. 3, March 2002, pp. 375-387
Hundertmark K.J., Shields G.F., Udina I.G., Bowyer R.T., Danilkin A.A. and C.C.
Schwartz.
We examined phylogeographic relationships of moose (Alces alces) worldwide to test the proposed existence of two geographic races and to infer the timing and extent of demographic processes underpinning the expansion of this species across the Northern
Hemisphere in the late Pleistocene. Sequence variation within the left hypervariable domain of the control region occurred at low or moderate levels worldwide and was structured geographically. Partitioning of genetic variance among regions indicated that isolation by distance was the primary agent for differentiation of moose populations but does not support the existence of distinct eastern and western races. Levels of genetic variation and structure of phylogenetic trees identify Asia as the origin of all extant mitochondrial lineages. A recent coalescence is indicated, with the most recent common ancestor dating to the last ice age. Moose have undergone two episodes of population expansion, likely corresponding to the final interstade of the most recent ice age and the onset of the current interglacial. Timing of expansion for the population in the Yakutia-
Manchuria region of eastern Asia indicates that it is one of the oldest populations of moose and may represent the source of founders of extant populations in North America, which were colonized within the last 15,000 years. Our data suggest an extended period of low population size or a severe bottleneck prior to the divergence and expansion of extant lineages and a recent, less-severe bottleneck among European lineages. Climate change during the last ice age, acting through contraction and expansion of moose habitat and the flooding of the Bering land bridge, undoubtedly was a key factor influencing the divergence and expansion of moose populations.

Marsh IB, Whittington RJ, O. Rourke B, Hyatt AD, Chisholm O. 2002
Rapid differentiation of Australian, European and American ranaviruses based on variation in
major capsid protein gene sequence. Mol Cell Probes.;16 (2):137-151.
Dis Aquat Organ 2000 Apr 20;40(3):195-201
Ichthyophonus-like infection in wild amphibians from Quebec, Canada.
Mikaelian I, Ouellet M, Pauli B, Rodrigue J, Harshbarger JC, Green DM.
Myositis associated with infection by Ichthyophonus-like organisms was diagnosed in 35 of 260
(13%) wild amphibians collected in Quebec, Canada, from 1959 to 1964 (n
= 30), and 1992 to
1999 (n = 230). Infection was diagnosed in 17 green frogs Rana clamitans,
9 wood frogs R.
sylvatica, 4 red-spotted newts Notophthalmus viridescens, 3 bullfrogs R. catesbeiana, 1 spring
peeper Pseudacris crucifer, and 1 pickerel frog R. palustris. The spring peeper and one of the
bullfrogs were collected in 1964 from the Mont Saint-Hilaire Biosphere
Reserve, indicating
long-term presence of the organism. Spores of the organisms invaded striated muscle fibers and
were associated with variable degrees of granulomatous and eosinophilic inflammation. Infection
was considered fatal in 2 green frogs, 1 wood frog, and 1 red-spotted newt.
It was considered
potentially significant in 3 additional green frogs in which up to 100% of the fibers of some
muscles were replaced by spores associated with a severe granulomatous reaction.
Ultrastructural features of Ichthyophonus-like spores included a thick trilaminated wall, a
paramural cytoplasm, multiple nuclei, oval mitochondria with short tubulovesicular cristae and
numerous ribosomes. This report represents 4 new host records and shows that ichthyophonosis
is enzootic in amphibians from Quebec.
Marsh I.B., Whittington R.J., Rourke O.B., Hyatt A.D. and O. Chisholm. 2002. Rapid differentiation of Australian, European and American ranaviruses based on variation in major capsid protein gene sequence. Mol Cell Probes. 16 (2): 137-151.