Browsing by Subject "Oceans"
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DNA amplicons using arbitrary primers distinguish polymorphic loci among mangrove thraustochytrid genomes - In OCEANS 2007 - Europe, 2007 - Institute of Electrical and Electronics EngineersThraustochytrids - lightly-pigmented estuarine and marine microheterotrophs, taxonomically aligned with heterokont algae - are of great biotechnological interest because they produce substantial amounts of polyunsaturated fatty acids (PUFAs) especially docosahexaenoic acid (DHA:6n3). In this study, twenty-seven strains, isolated from twenty mangrove areas in the Philippine archipelago, were mass-produced in axenic flask cultures using high-glucose medium with continuous agitation. Polymorphic loci of thraustochytrid genomes, determined using four arbitrary primers (OPC02, OPC05, OPC07 and OPC08) in PCR analysis, were randomly amplified as molecular markers for genetic fingerprinting. Electrophoretic banding patterns of DNA amplicons, recognized based on nucleic acid size, were scored on data matrix and analyzed using Jaccard's coefficient and single-linkage hierarchical clustering to characterize degree of genetic relatedness among thraustochytrids. Conclusively, nearest-neighbor dendrogram of randomly amplified polymorphic DNAs (RAPDs) markers classify the strains into two monophenetic clades, representing the two major genera: Schizochytrium and Thraustochytrium.
Microsatellite and mitochondrial haplotype diversity reveals population differentiation in the tiger shrimp (Penaeus monodon) in the Indo-Pacific region -
Animal Genetics, 2008 - International Society for Animal GeneticsThe black tiger shrimp (Penaeus monodon) is an ecologically and economically important penaeid species and is widely distributed in the Indo-Pacific region. Here we investigated the genetic diversity of P. monodon (n = 355) from eight geographical regions by genotyping at 10 microsatellite loci. The average observed heterozygosity at various loci ranged from 0.638 to 0.743, indicating a high level of genetic variability in this region. Significant departures from Hardy–Weinberg equilibrium caused by heterozygote deficiency were recorded for most loci and populations. Pairwise FST and RST values revealed genetic differentiation among the populations. Evidence from the assignment test showed that the populations in the West Indian Ocean were unique, whereas other populations examined were partially admixed. In addition, the non-metric multidimensional scaling analysis indicated the presence of three geographic groups in the Indo-Pacific region, i.e. the African populations, a population from western Thailand and the remaining populations as a whole. We also sequenced and analysed the mitochondrial control region (mtCR) in these shrimp stocks to determine whether the nuclear and mitochondrial genomes show a similar pattern of genetic differentiation. A total of 262 haplotypes were identified, and nucleotide divergence among haplotypes ranged from 0.2% to 16.3%. Haplotype diversity was high in all populations, with a range from 0.969 to 1. Phylogenetic analysis using the mtCR data revealed that the West Indian Ocean populations were genetically differentiated from the West Pacific populations, consistent with the microsatellite data. These results should have implications for aquaculture management and conservation of aquatic diversity.