High Connectivity in the Deepwater Snapper Pristipomoides filamentosus (Lutjanidae) across the Indo-Pacific with Isolation of the Hawaiian Archipelago

In the tropical Indo-Pacific, most phylogeographic studies have focused on the shallow-water taxa that inhabit reefs to approximately 30 m depth. Little is known about the large predatory fishes, primarily snappers (subfamily Etelinae) and groupers (subfamily Epinephelinae) that occur at 100–400 m. These long-lived, slow-growing species support fisheries across the Indo-Pacific, yet no comprehensive genetic surveys within this group have been conducted. Here we contribute the first range-wide survey of a deepwater Indo-Pacific snapper, Pristipomoides filamentosus, with special focus on Hawai'i. We applied mtDNA cytochrome b and 11 microsatellite loci to 26 samples (N = 1,222) collected across 17,000 km from Hawai'i to the western Indian Ocean. Results indicate that P. filamentosus is a highly dispersive species with low but significant population structure (mtDNA ΦST = 0.029, microsatellite FST = 0.029) due entirely to the isolation of Hawai'i. No population structure was detected across 14,000 km of the Indo-Pacific from Tonga in the Central Pacific to the Seychelles in the western Indian Ocean, a pattern rarely observed in reef species. Despite a long pelagic phase (60–180 days), interisland dispersal as adults, and extensive gene flow across the Indo-Pacific, P. filamentosus is unable to maintain population connectivity with Hawai'i. Coalescent analyses indicate that P. filamentosus may have colonized Hawai'i 26 K–52 K y ago against prevailing currents, with dispersal away from Hawai'i dominating migration estimates. P. filamentosus harbors low genetic diversity in Hawai'i, a common pattern in marine fishes, and our data indicate a single archipelago-wide stock. However, like the Hawaiian Grouper, Hyporthodus quernus, this snapper had several significant pairwise comparisons (FST) clustered around the middle of the archipelago (St. Rogatien, Brooks Banks, Gardner) indicating that this region may be isolated or (more likely) receives input from Johnston Atoll to the south

An Anomalous Type IV Secretion System in Rickettsia Is Evolutionarily Conserved

Bacterial type IV secretion systems (T4SSs) comprise a diverse transporter family functioning in conjugation, competence, and effector molecule (DNA and/or protein) translocation. Thirteen genome sequences from Rickettsia, obligate intracellular symbionts/pathogens of a wide range of eukaryotes, have revealed a reduced T4SS relative to the Agrobacterium tumefaciens archetype (vir). However, the Rickettsia T4SS has not been functionally characterized for its role in symbiosis/virulence, and none of its substrates are known.Superimposition of T4SS structural/functional information over previously identified Rickettsia components implicate a functional Rickettsia T4SS. virB4, virB8 and virB9 are duplicated, yet only one copy of each has the conserved features of similar genes in other T4SSs. An extraordinarily duplicated VirB6 gene encodes five hydrophobic proteins conserved only in a short region known to be involved in DNA transfer in A. tumefaciens. virB1, virB2 and virB7 are newly identified, revealing a Rickettsia T4SS lacking only virB5 relative to the vir archetype. Phylogeny estimation suggests vertical inheritance of all components, despite gene rearrangements into an archipelago of five islets. Similarities of Rickettsia VirB7/VirB9 to ComB7/ComB9 proteins of epsilon-proteobacteria, as well as phylogenetic affinities to the Legionella lvh T4SS, imply the Rickettsiales ancestor acquired a vir-like locus from distantly related bacteria, perhaps while residing in a protozoan host. Modern modifications of these systems likely reflect diversification with various eukaryotic host cells.We present the rvh (Rickettsiales vir homolog) T4SS, an evolutionary conserved transporter with an unknown role in rickettsial biology. This work lays the foundation for future laboratory characterization of this system, and also identifies the Legionella lvh T4SS as a suitable genetic model

An update of genetic shock identification of Chinook salmon in the Pacific Northwest: test fisheries in California

213-Analyzing the stock composition of mixed-stock fisheries using genetic stock identification (GSI) procedures was developed for chinook salmon in the early 1980s when an incipient baseline was focused in theColumbia River basin. The current coastwide baseline of allozyme (protein) genetic loci includes approximately 75% of the major contributing populations from California to western Alaska for over 30 polymorphic loci. We review the 2-decade history of GSI studies of chinook salmon in fishery applications in the Pacific Northwest. By summarizing GSI results for four test fisheries in California, we demonstrate the use of a regional segment of the current baseline to monitor critically depleted stocks. Average FST is 0.099, with 12 loci FST > 0.05, in a 28 locus/53 population dataset from southern Oregon to southern California. Seven stock groups are recognized based on a multilocus pattern of differentiation that coincides with watersheds and coastal affiliations. Simulated mixture analyses indicate that stock groups are well resolved: percent correct assignment is 83% for Central Valley spring-run, but >92% for all other groups. Simulated mixture analyses also indicated that it is difficult to distinguish between mixtures with low levels (=/<1%) of Central Valley winter- or spring-run stocks given the present dataset. GSI estimates for four test fisheries indicate that Central Valley fall- and late fall-run chinook salmon comprised the majority of each mixture (89 to 95%). Critical or endangered stock groups were detected in test fisheries in the 1997 Point Conception fishery (3% Sacramento River winter-run) and in the 1999 Bodega Bay fishery (2.8% Upper Klamath-Trinity rivers). Preliminary regional baselines for intron and microsatellite loci show promise for added stock discrimination among chinook salmonpopulations. GSI projects are increasingly involving multiple agencies and using multicharacter procedures. Continued GSI monitoring of chiABSTRACT FROM AUTHORhttp://gbic.tamug.edu/request.ht

Genetic variation in a continuously breeding population of Danaus plexippus L. (Lepidoptera: Nymphalidae)

Variation at 4 genetic loci (Pgm; Me; Idh; Hbdh) was studied in a population of monarchs (Danaus plexippus L.) not subject to migration to overwintering sites. Adult insects were sampled from 18 milkweed patches in 5 widely spaced locations in south-east Queensland (Australia). Genetic differentiation between sub-populations (patches) was high (F= 0·032). For 2 loci (Me and Idh) both males and females showed significant differentiation between patches. Idh showed a significant cline with latitude in males only and Me showed no apparent geographic pattern in either sex. Both loci showed significant differences in gene frequencies between sexes. Possible mechanisms for maintaining these differences are discussed