Genetic Variation betweenBiomphalaria alexandrinaSnails Susceptible and Resistant toSchistosoma mansoniInfection

Much effort has been made to control schistosomiasis infection in Egypt. However, enduring effects from such strategies have not yet been achieved. In this study, we sought to determine the genetic variability related to the interaction betweenBiomphalaria alexandrinasnails andSchistosoma mansoni. Using RAPD-PCR with eight (10 mers) random primers, we were able to determine the polymorphic markers that differed between snails susceptible and resistant toSchistosoma mansoniinfection using five primers out of the eight. Our results suggest that the RAPD-PCR technique is an efficient means by which to compare genomes and to detect genetic variations between schistosomiasis intermediate hosts. The RAPD technique with the above-noted primers can identify genomic markers that are specifically related to theBiomphalaria alexandrina/Schistosoma mansonirelationship in the absence of specific nucleotide sequence information. This approach could be used in epidemiologic surveys to investigate genetic diversity amongBiomphalaria alexandrinasnails. The ability to determine resistant markers inBiomphalaria alexandrinasnails could potentially lead to further studies that use refractory snails as agents to control the spread of schistosomiasis.

Revision of Australian jumping spider genus Servaea Simon 1887 (Aranaea: Salticidae) including use of DNA sequence data and predicted distributions

The genus Servaea Simon 1887 is revised and redefined. Descriptions and identification keys are provided to the following sixspecies, of which three are described as new: Servaea incana (Karsch 1878), Servaea narraweena n. sp., Servaea melaina n.sp., Servaea spinibarbis Simon 1909, Servaea villosa (Keyserling 1881) and Servaea zabkai n. sp. The type species of thegenus, Servaea vestita (L. Koch 1879), is proposed here to be a junior synonym of Servaea incana. In addition to the diagnosesand descriptions, distributional and nucleotide sequence information are provided. DNA sequence data for the segment of COIused in other salticid studies was obtained for the five species for which suitable material was available. Intraspecific variationin S. villosa and S. incana were studied in more detail. Within-species divergence was S. melaina and S spinibarbis, had adjacent predicted distributions, one coastal on sandy soils and one inland on other soil types.

Imbroglios of Viral Taxonomy: Genetic Exchange and Failings of Phenetic Approaches

ABSTRACT The practice of classifying organisms into hierarchical groups originated with Aristotle and was codified into nearly immutable biological law by Linnaeus. The heart of taxonomy is the biological species, which forms the foundation for higher levels of classification. Whereas species have long been established among sexual eukaryotes, achieving a meaningful species concept for prokaryotes has been an onerous task and has proven exceedingly difficult for describing viruses and bacteriophages. Moreover, the assembly of viral “species” into higher-order taxonomic groupings has been even more tenuous, since these groupings were based initially on limited numbers of morphological features and more recently on overall genomic similarities. The wealth of nucleotide sequence information that catalyzed a revolution in the taxonomy of free-living organisms necessitates a reevaluation of the concept of viral species, genera, families, and higher levels of classification. Just as microbiologists discarded dubious morphological traits in favor of more accurate molecular yardsticks of evolutionary change, virologists can gain new insight into viral evolution through the rigorous analyses afforded by the molecular phylogenetics of viral genes. For bacteriophages, such dissections of genomic sequences reveal fundamental flaws in the Linnaean paradigm that necessitate a new view of viral evolution, classification, and taxonomy.

Characterization of genomic PIG-A gene: a gene for glycosylphosphatidylinositol-anchor biosynthesis and paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia characterized by the presence of abnormal subpopulations of blood cells that are deficient in surface expression of glycosylphosphatidylinositol (GPI)-anchored proteins. Recent studies showed that the gene termed PIG-A, which participates in the first step of GPI-anchor biosynthesis, is mutated in the abnormal blood cells from patients with PNH. In this study the genomic PIG-A gene was cloned and characterized to obtain nucleotide sequence information for analyzing somatic mutations of PIG-A in patients with PNH. The PIG-A gene is at least 17 kb long and has six exons. The exon-intron boundaries and 583 bp of the 5′ flanking region were sequenced. The 5′ flanking region has no TATA-like sequence, but includes four CAAT boxes, two AP-2 sequences, and a CRE sequence, some of which are present in regions necessary for the promoter activity. We report pairs of oligonucleotide primers for polymerase chain reaction that should be useful to amplify and analyze various regions of the PIG-A gene in patients with PNH.

Characterization of genomic PIG-A gene: a gene for glycosylphosphatidylinositol-anchor biosynthesis and paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia characterized by the presence of abnormal subpopulations of blood cells that are deficient in surface expression of glycosylphosphatidylinositol (GPI)-anchored proteins. Recent studies showed that the gene termed PIG-A, which participates in the first step of GPI-anchor biosynthesis, is mutated in the abnormal blood cells from patients with PNH. In this study the genomic PIG-A gene was cloned and characterized to obtain nucleotide sequence information for analyzing somatic mutations of PIG-A in patients with PNH. The PIG-A gene is at least 17 kb long and has six exons. The exon-intron boundaries and 583 bp of the 5′ flanking region were sequenced. The 5′ flanking region has no TATA-like sequence, but includes four CAAT boxes, two AP-2 sequences, and a CRE sequence, some of which are present in regions necessary for the promoter activity. We report pairs of oligonucleotide primers for polymerase chain reaction that should be useful to amplify and analyze various regions of the PIG-A gene in patients with PNH.