Microsatellite and mitochondrial haplotype diversity reveals population differentiation in the tiger shrimp (Penaeus monodon) in the Indo-Pacific region.

The 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 F(ST) and R(ST) 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.

The human PCPH proto-oncogene: cDNA identification, primary structure, chromosomal mapping, and expression in normal and tumor cells.

We identified a human cDNA encoding a 47-kDa protein that shares 78% and 87% identity with the products of the Syrian hamster and mouse PCPH proto-oncogenes respectively. The human homolog was localized by radiation-hybrid mapping to chromosome band 14q24.3, a region syntenic to the Pcph location on mouse chromosome 12. Northern analyses revealed that PCPH mRNA was widely distributed in normal human adult tissues, but its expression varied significantly among human tumor cells and cell lines of several tissue types, regardless of the level of expression in the corresponding normal tissues. The highest levels of PCPH mRNA and protein were detected in kidney and liver. However, PCPH was not expressed in the majority of human neoplasms tested, including kidney tumors. These data provide suggestive evidence for a possible association of the lack of PCPH expression to the neoplastic phenotype of human tumor cells. Our results should prove instrumental in designing studies to define the cellular function of the human PCPH proto-oncogene.