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Caccone A; Moriyama EN; Gleason JM; Nigro L; Powell JR 《Molecular biology and evolution》1996,13(9):1224-1232
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.
相似文献
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INTRoDUCTIoNlYho1iumrePensL,whiteclover,isaneconomicallyimportantplantspeciesintemperatepastures.Asbrieflyreportedby[1],ithas16pairsofchromosomes(2n=32).Asyet,nodetailedcytologicalexaminationofthisspecies,suchasC-banding,hasbeenrep0rted.Inthelastdecade,thetechnique0fC-bandinghasbeenusedt0examinehighlyrepeatedsequencesinplantchrom0s0mesandhasprovidedausefultoolf0rtheanalysis0fcyt0geneticstructureincr0pplants[2-71.Inplants,thechr0m0s0mall0calizationofhighlyrepeatedDNAsequencesbyinsituhybr… 相似文献
76.
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The period (per) locus has received much attention in molecular evolution
studies because it is one of the best studied "behavioral genes" and
because it offers insight into the evolution of repetitive sequences. We
studied most of the coding region of per in Drosophila willistoni and
confirmed previously observed patterns of conservation and divergence among
distantly related species. Five regions are so highly diverged that they
cannot be aligned, whereas a region encompassing the PAS domain is very
conserved. Structural and nucleotide polymorphism patterns in the
willistoni group are not the same as those observed in previously studied
species. We sequenced the region homologous to the highly polymorphic
threonine-glycine repeat of D. melanogaster in multiple strains of D.
willistoni, as well as in other members of willistoni group, and found an
unusual amount of conservation in this region. However, the next
nonconserved region downstream in the sequence is quite variable and
polymorphic for the number of repeated glycines. The glycine codon usage is
significantly different in this glycine repeat as compared to other parts
of the gene. We were able to plot the directionality of change in the
glycine repeat region onto a phylogeny and find that the addition of
glycines is the general trend with the diversification of the willistoni
group.
相似文献
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M Hunzicker-Dunn N Lorenzini R E Cutler R C Ekstrom E T Maizels 《Biology of reproduction》1989,40(3):486-494
In a previous report on the ontogeny of the ovarian adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase activity during prepubertal development of the rat, we concluded that the 4-fold decline in cAMP-dependent protein kinase activity observed in ovaries of 21- to 23-day-old rats was due to the presence of a heat-labile inhibitor in the ovarian extracts (Hunzicker-Dunn et al., 1984). We developed an assay for this ovarian kinase inhibitor activity that was based on the observation that ovarian cytosol added to an exogenous catalytic subunit of cAMP-dependent protein kinase caused a time-dependent and ovarian cytosol protein concentration-dependent inhibition of exogenous catalytic subunit phosphotransferase activity. The present studies were conducted to evaluate the basis for this catalytic subunit inhibitor present in soluble rat ovarian extracts of prepubertal-aged rats. This inhibitor activity was absent from cytosol extracts of rat corpora lutea, rat liver, rabbit follicles, and rabbit corpora lutea. Inhibitor activity present in rat ovarian cytosol was not attributable to insufficient levels of the phosphorylation substrate Kemptide. Inhibitor activity was also not related to the presence of the large amount of catalytic subunit-free regulatory subunit of the cAMP-dependent protein kinase present in ovarian extracts of late juvenile-aged rats. Inhibitor activity, however, did correlate with an endogenous adenosine triphosphatase (ATPase) activity that reduced assay ATP concentrations below levels needed to accurately measure phosphotransferase activity, despite the presence of sodium fluoride (an ATPase inhibitor) and ATP concentrations 5- to 15-fold greater than the Km of the kinase for ATP.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
80.