18S rRNA data indicate that Aschelminthes are polyphyletic in origin and consist of at least three distinct clades

The Aschelminthes is a collection of at least eight animal phyla, historically grouped together because the absence of a true body cavity was perceived as a pseudocoelom. Analyses of 18S rRNA sequences from six Aschelminth phyla (including four previously unpublished sequences) support polyphyly for the Aschelminthes. At least three distinct groups of Aschelminthes were detected: the Priapulida among the protostomes, the Rotifera-Acanthocephala as a sister group to the protostomes, and the Nematoda as a basal group to the triploblastic Eumetazoa.      

Malic enzyme,phosphoglucomutase and phosphoglucose isomerase isozymes inTrichogramma [Hym.: Trichogrammatidae]

ME, PGM and PGI electrophoretic banding patterns in 20 laboratory cultures representing 14 species ofTrichogramma were studied. Variations in PGM were found inT. exiguum, T. marylandense, andT. pretiosum. PGI also showed variation inT. exiguum, T. marylandense, T. minutum, andT. parkeri. However, ME variations were found only inT. pretiosum. Based on progeny analyses, we concluded that ME is a tetramer inTrichogramma with fast and slow alleles at a single locus, and that both PGM and PGI have a single locus and each has four alleles. PGM is a monomer, but PGI is a dimer.

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Résumé Les bandes électrophorétiques de l'enzyme malique, de la P.G.M. et de la P.G.I. ont été étudiées chez 20 souches de laboratoire représentant 14 espèces deTrichogramma. Des variations de la P.G.M. ont été trouvées chezT. exiguum, T. marylandense etT. pretiosum. La. P.G.I. montre aussi des variations chezT. exiguum, T. marylandense, T. minutum etT. parkeri. Par contre, des variations de l'enzyme malique ne sont trouvées que chezT. pretiosum. En nous basant, sur l'analyse de progénitures, nous avons conclu que l'enzyme malique est un tétramère chezTrichogramma comprenant un allèle “lent” et un alléle “rapide”, à un seul locus, et que la P.G.M. et la P.G.I. ont chacune un seul locus à quatre allèles. La P.G.M. est un monomère mais la P.G.I. est un dimère.

     

A molecular phylogeny for the Drosophila melanogaster subgroup and the problem of polymorphism data

Drosophila melanogaster belongs to a closely related group of eight species collectively known as the melanogaster subgroup; all are native to sub-Saharan Africa and islands off the east coast of Africa. The phylogenetic relationships of most species in this subgroup have been well documented; however, the three most closely related species, D. simulans, D. sechellia, and D. mauritiana, have remained problematic from a phylogenetic standpoint as no data set has unambiguously resolved them. We present new DNA sequence data on the nullo and Serendipity-alpha genes and combine them with all available nuclear DNA sequence data; the total data encompass 12 genes and the ITS of rDNA. A methodological problem arose because nine of the genes had information on intraspecific polymorphisms in at least one species. We explored the effect of inclusion/exclusion of polymorphic sites and found that it had very little effect on phylogenetic inferences, due largely to the fact that 82% of polymorphisms are autapomorphies (unique to one species). We have also reanalyzed our previous DNA-DNA hybridization data with a bootstrap procedure. The combined sequence data set and the DNA-DNA hybridization data strongly support the sister status of the two island species, D. sechellia and D. mauritiana. This at least partially resolves what had been a paradox of parallel evolution in these two species.      

Chromosomal localization of a tandemly repeated DNA sequence in Trifolium repens L

INTRoDUCTIoNlYho1iumrePensL,whiteclover,isaneconomicallyimportantplantspeciesintemperatepastures.Asbrieflyreportedby[1],ithas16pairsofchromosomes(2n=32).Asyet,nodetailedcytologicalexaminationofthisspecies,suchasC-banding,hasbeenrep0rted.Inthelastdecade,thetechnique0fC-bandinghasbeenusedt0examinehighlyrepeatedsequencesinplantchrom0s0mesandhasprovidedausefultoolf0rtheanalysis0fcyt0geneticstructureincr0pplants[2-71.Inplants,thechr0m0s0mall0calizationofhighlyrepeatedDNAsequencesbyinsituhybr…