Steffi Gäbler-Schwarz

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 August 2009-30 September 2009

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis × Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross‐tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

STAMP: Extensions to the STADEN sequence analysis package for high throughput interactive microsatellite marker design

BackgroundMicrosatellites (MSs) are DNA markers with high analytical power, which are widely used in population genetics, genetic mapping, and forensic studies. Currently available software solutions for high-throughput MS design (i) have shortcomings in detecting and distinguishing imperfect and perfect MSs, (ii) lack often necessary interactive design steps, and (iii) do not allow for the development of primers for multiplex amplifications. We present a set of new tools implemented as extensions to the STADEN package, which provides the backbone functionality for flexible sequence analysis workflows. The possibility to assemble overlapping reads into unique contigs (provided by the base functionality of the STADEN package) is important to avoid developing redundant markers, a feature missing from most other similar tools.ResultsOur extensions to the STADEN package provide the following functionality to facilitate microsatellite (and also minisatellite) marker design: The new modules (i) integrate the state-of-the-art tandem repeat detection and analysis software PHOBOS into workflows, (ii) provide two separate repeat detection steps – with different search criteria – one for masking repetitive regions during assembly of sequencing reads and the other for designing repeat-flanking primers for MS candidate loci, (iii) incorporate the widely used primer design program PRIMER 3 into STADEN workflows, enabling the interactive design and visualization of flanking primers for microsatellites, and (iv) provide the functionality to find optimal locus- and primer pair combinations for multiplex primer design. Furthermore, our extensions include a module for storing analysis results in an SQLite database, providing a transparent solution for data access from within as well as from outside of the STADEN Package.ConclusionThe STADEN package is enhanced by our modules into a highly flexible, high-throughput, interactive tool for conventional and multiplex microsatellite marker design. It gives the user detailed control over the workflow, enabling flexible combinations of manual and automated analysis steps. The software is available under the OpenBSD License [1, 2]. The high efficiency of our automated marker design workflow has been confirmed in three microsatellite development projects.

CURRENT KNOWLEDGE OF THE LIFE CYCLES OF PHAEOCYSTIS GLOBOSA AND PHAEOCYSTIS ANTARCTICA (PRYMNESIOPHYCEAE)1

Despite continuous efforts since the 1950s and more recent advances in culturing flagellates and nonflagellate cells of the prymnesiophyte Phaeocystis, a number of different life‐cycle models exist today that appear to apply for P. globosa Scherff. and P. antarctica G. Karst., both spherical colony formers. In one such model, this life cycle consists of three different flagellates and one nonmotile cell stage that is embedded in carbohydrate matrix‐forming colonies of different sizes and forms. Recently, noncolonial aggregates of diploid nonmotile cells attached to surfaces of diatoms were put forward as a new stage in the sexual life cycle of P. antarctica. However, it can be discussed that these “attached aggregates” (AAs) are an intermediate between motile diploid flagellates, with their well‐known tendency to adhere to surfaces, and the young spherical colony with its diploid nonmotile cells, which in nature is commonly found attached to diatoms. A life‐cycle model pertaining to both P. globosa and P. antarctica is presented.

A puzzle with many pieces: the genetic structure and diversity of Phaeocystis antarctica Karsten (Prymnesiophyta)

Strong ocean current systems characterize the Southern Ocean. The genetic structure of marine phytoplankton species is believed to depend mainly on currents. Genetic estimates of the relatedness of populations of phytoplankton species therefore should provide a proxy showing to what extent different geographic regions are interconnected by the ocean current systems. In this study, spatial and temporal patterns of genetic diversity were studied in the circumpolar prymnesiophyte Phaeocystis antarctica Karsten using seven nuclear microsatellite loci. Analyses were conducted for 86 P. antarctica isolates sampled around the Antarctic continent between 1982 and 2007. The results revealed high genetic diversity without single genotypes recurring even among isolates within a bloom or originating from the same bucket of water. Populations of P. antarctica were significantly differentiated among the oceanic regions. However, some geographically distant populations were more closely related to each other than they were to other geographically close populations. Temporal haplotype turnover within regions was also suggested by the multilocus fingerprints. Our data suggest that even within blooms of P. antarctica genetic diversity and population sizes are large but exchange between different regions can be limited. Positive and significant inbreeding coefficients hint at further regional substructure of populations, suggesting that patches, once isolated from one another, may not reconnect. These data emphasize that even for planktonic species in a marine ecosystem that is influenced by strong currents, significant breaks in gene flow may occur.

PERMANENT GENETIC RESOURCES NOTE: Permanent Genetic Resources added to Molecular Ecology Resources Database 1 August 2010 30 September 2010

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis × Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross‐tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.