摘要:

AbstractWe have used a PCR assay to screen 404 insects and related arthropods formarinerelements using primers corresponding to amino acids conserved between themarinerelements ofDrosophila mauritianaand a moth,Hyalophora cecropia.Potentialmarinerelements were detected in sixty‐three species, representing ten insect orders as well as a centipede and a mite. Phylogenetic analysis of the PCR fragment sequences from thirty species identifies five major subfamilies ofmariners.Many species have representatives of multiple subfamilies in their genomes, and the Medfly is an extreme example with representatives of four subfamilies. Two instances of recent horizontal transfer ofmarinerelements include at least three species each. The widespread but sporadic distribution ofmarinerelements suggests they are excellent candidates for development as transformation vectors for non‐drosophil

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00132.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn the parthenogeneticBacillus atticus atticus, widespread over most of the Mediterranean basin, a highly repeated satellite DNA (BaB300) has been detected and analysed. Bgl II, Taq I and Alu I restriction enzymes cut 316 bp long repeating units from the BaB300 family. These are non‐coding, AT rich and well conserved in the three isolated populations studied. Byin situhybridization, the satellite has been located in the centromeric heterochromatin of a subset of medium‐and small‐sized chromosomes, including the Xs. Related sequences have been found in the bisexualB. grandii grandiiand in its specific hybridB. whitei (=B. rossius/grandii grandii), while they are absent fromB. rossius redtenbacheri.These data support the genetic affinity relationships within the genusBacillusinferred from morphological, allozymic and karyological data. They also encourage further comparisons amongBacillushybrids, in order to trace their parental genomes in the hybrid nuclei, and within theB. atticuscomplex (i.e. additional samples ofB. a. atticusand diploid/triploid cytotypes ofB. a. carius)to study repetitive DNA turnover in unisexual orga

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00133.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractCyclodiene insecticide resistance has accounted for over 60% of reported cases of insecticide resistance. inDrosophila melanogasterresistance is associated with a single base pair substitution in the GABA receptor/chloride ion channel geneRdl.This substitution predicts the replacement of an alanine with a serine in the second membrane spanning domain, the region thought to line the chloride ion channel pore. Here we report, via the use of degenerate primers in the polymerase chain reaction, that precisely the same substitution is present in three pests from three different insect orders: the house fiy (Diptera), red flour beetle (Coleoptera) and American cockroach (Dicty‐optera). This finding suggests that there are a limited number of mutations that can confer resistance to cyclodienes, putative channel blockers, while still maintaining adequate chloride ion channel function. The conservation of the resistance‐associated mutation betweenDrosophilaand pest insects directly validates the approach of using this insect as a model system for isolating and studying resistance genes. The importance of single base pair substitutions in the evolution of pesticide resistance and in the design of molecular monitoring techniques is discus

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00134.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe dihydrofolate reductase ampiicon in metho‐trexate‐resistant mosquito cells provides an amplified gene in insects that can be compared directly to the corresponding amplified locus in mammalian cells. A clonedAedes albopictusdihydrofolate reductase gene was used as a probe to examine the structure of dihydrofolate reductase alleles in sensitive and resistant cells. In wild type cells, two distinct alleles could be distinguished by restriction fragment length polymorphisms, one of which was amplified in methotrexate‐resistant cells. Subsequent to amplification, an additional polymorphism at a ten base‐pairXmrArecognition site indicated that the amplified mosquito gene is subject to genetic changes similar to those that have been described in amplified genes from mammalian cells. Pulsed‐field gel electrophoresis was used to determine that the minimum size of the mosquito dihydrofolate reductase ampiicon was 140 kilobases; ethidium bromide staining patterns suggested a size of at least 233 kilobases. Dihydrofolate reductase probes hybridized to distinct locations in five of the thirteen chromosomes in Mtx‐5011‐128 cells, indicating that the amplified DNA probably occurs as tandem direct or inv

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00135.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe ribosomal DNA (rDNA) ofRhagoletis pomonellawas localized within both salivary gland polytene chromosomes and somatic cell mitotic chromosomes byin situhybridization using the heterospecificDrosophila melanogasterrDNA clone, Dm238.In situhybridization analysis of polytene nuclei showed that RpomonellarDNA is located in the nucleolus and adjacent granular network of chromosome 1. The site of origin of rDNA is within this isomorphic granular network. The preservation of nucleolar ultrastructure in some polytene chromosome preparations allowed light microscope localization ofR. pomonellarDNA to the apparent periphery of fibrillar centres within fibrillar complexes. In somatic cell nuclei, DM238 hybridized to the nucleolus organizing region (NOR) located on chromosome 1 at the site of the secondary constriction. The frequency distribution of heteromorphisms for rDNA content, differential appearance of secondary constrictions, non‐pairing of the NOR and differences in homologue lengths suggests that the structural differentiation of this region in chromosome 1 is sex linked. This the first published description of the salivary gland polytene chromosomes fromR. pomonella, and we include a tentative karyotype description, polytene chromosome maps and comments on their suitability for banding and molecular analysi

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00136.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA cytoplasmic actin gene fromBombyx moriintroduced intoDrosophila melanogasterby P‐element mediated transformation, is efficiently transcribed in larvae, pupae and adults of the host. The exogenous mRNA has the same size as the one observed in theBombyxcells and the intron located within the coding region is properly excised, indicating a correct recognition of the exogenous sequences by theDrosophilatranscriptional and splicing machineries. The expression of theBombyxgene inDrosophilatissues was determined by transforming flies with a hybrid gene in which a large part of theBombyxactin coding sequences was replaced by those of the bacterial lac Z gene. This chimaeric gene is specifically and highly expressed, from the embryo to the adult of the transgenic lines, in tissues of endodermal origin, the midgut and its derivatives, i.e. gastric caeca, the outer layer of the proventriculus, and in the Malpighian tubules. This gene is also expressed, at a lower level, in germ cells but restricted to the sixteen cell cysts during previtel‐logenesis. The expression of theBombyxgene during development of transgenic flies was compared to that of the twoDrosophilaendogenous cytoplasmic actin genes and the results are discus

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00137.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractSequence data from a non‐coding nuclear DNA segment (CpnI‐1) was used to investigate the divergence between Spanish and French subspecies of the grasshopperChorthippuspara/us which form a hybrid zone in the Pyrenees. The spatial distribution of eighteen Cpnl‐1 sequence haplotypes from eighteen French and fifteen Spanish populations and phylogenetic analyses using both distance and parsimony procedures provide strong evidence that the Py renean hybrid zone was formed by postglacial secondary contact and that the French subspecies arose by range expansion from a Balkan or Italian refugium. In addition, the data provide evidence for subdivision between grasshoppers from Northern Spain and those from Central and Pyrenean Spanish popula

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00138.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY