Assuntos
Cães/genética , Mapeamento de Híbridos Radioativos , Animais , Linhagem Celular , Cricetinae , Marcadores Genéticos , Humanos , SinteniaAssuntos
Cães/genética , Proteínas do Tecido Nervoso/genética , Polimorfismo Genético , Mapeamento de Híbridos Radioativos , Animais , Sequência de Bases , Primers do DNA , Eletroforese em Gel de Ágar , Frequência do Gene , Humanos , Dados de Sequência Molecular , Análise de Sequência de DNA , Homologia de SequênciaAssuntos
Doenças do Cão/genética , Displasia Ectodérmica/veterinária , Proteínas de Membrana/genética , Fenótipo , Polimorfismo Genético , Mapeamento de Híbridos Radioativos , Animais , Sequência de Bases , Análise Mutacional de DNA , Primers do DNA , Cães , Displasia Ectodérmica/genética , Ectodisplasinas , Genes Dominantes/genética , Linhagem , Especificidade da EspécieRESUMO
Radiation hybrid (RH) map construction allows investigators to locate both type I and type II markers on a given genome map. The process is composed of two steps. The first consists of determining the pattern distribution of a set of markers within the different cell lines of an RH panel. This is mainly done by polymerase chain reaction (PCR) amplification and gel electrophoresis, and results in a series of numbers indicating the presence or the absence of each marker in each cell line. The second step consists of a comparison of these numbers, using various algorithms, to group and then order markers. Because different algorithms may provide (slightly) different orders, we have compared the merits of the MultiMap and TSP/CONCORDE packages using a data set of information currently under analysis for construction of the canine genome RH map.
Assuntos
Mapeamento de Híbridos Radioativos/métodos , Software , Animais , CãesRESUMO
Sinorhizobium meliloti is an alpha-proteobacterium that forms agronomically important N(2)-fixing root nodules in legumes. We report here the complete sequence of the largest constituent of its genome, a 62.7% GC-rich 3,654,135-bp circular chromosome. Annotation allowed assignment of a function to 59% of the 3,341 predicted protein-coding ORFs, the rest exhibiting partial, weak, or no similarity with any known sequence. Unexpectedly, the level of reiteration within this replicon is low, with only two genes duplicated with more than 90% nucleotide sequence identity, transposon elements accounting for 2.2% of the sequence, and a few hundred short repeated palindromic motifs (RIME1, RIME2, and C) widespread over the chromosome. Three regions with a significantly lower GC content are most likely of external origin. Detailed annotation revealed that this replicon contains all housekeeping genes except two essential genes that are located on pSymB. Amino acid/peptide transport and degradation and sugar metabolism appear as two major features of the S. meliloti chromosome. The presence in this replicon of a large number of nucleotide cyclases with a peculiar structure, as well as of genes homologous to virulence determinants of animal and plant pathogens, opens perspectives in the study of this bacterium both as a free-living soil microorganism and as a plant symbiont.
Assuntos
Cromossomos Bacterianos/genética , Sinorhizobium meliloti/genética , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Divisão Celular/genética , Movimento Celular/genética , Cromossomos Artificiais Bacterianos/genética , Reparo do DNA/genética , Replicação do DNA/genética , DNA Bacteriano/genética , DNA Circular/genética , Metabolismo Energético/genética , Fabaceae/microbiologia , Duplicação Gênica , Genes Bacterianos , Dados de Sequência Molecular , Plantas Medicinais , Replicon/genética , Análise de Sequência de DNA , Transdução de Sinais/genética , Simbiose , Transcrição Gênica/genética , Virulência/genéticaRESUMO
The scarcity of usable nitrogen frequently limits plant growth. A tight metabolic association with rhizobial bacteria allows legumes to obtain nitrogen compounds by bacterial reduction of dinitrogen (N2) to ammonium (NH4+). We present here the annotated DNA sequence of the alpha-proteobacterium Sinorhizobium meliloti, the symbiont of alfalfa. The tripartite 6.7-megabase (Mb) genome comprises a 3.65-Mb chromosome, and 1.35-Mb pSymA and 1.68-Mb pSymB megaplasmids. Genome sequence analysis indicates that all three elements contribute, in varying degrees, to symbiosis and reveals how this genome may have emerged during evolution. The genome sequence will be useful in understanding the dynamics of interkingdom associations and of life in soil environments.
Assuntos
Genoma Bacteriano , Análise de Sequência de DNA , Sinorhizobium meliloti/genética , Simbiose/genética , Aderência Bacteriana , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Cromossomos Bacterianos/genética , Biologia Computacional , Elementos de DNA Transponíveis , Metabolismo Energético/genética , Evolução Molecular , Duplicação Gênica , Genes Bacterianos , Genes Essenciais , Genes Reguladores , Medicago sativa/microbiologia , Nitrogênio/metabolismo , Fixação de Nitrogênio/genética , Plasmídeos , Polissacarídeos Bacterianos/genética , Replicon , Rhizobiaceae/genética , Sinorhizobium meliloti/fisiologiaRESUMO
We present the sequence of a contiguous 2.63 Mb of DNA extending from the tip of the X chromosome of Drosophila melanogaster. Within this sequence, we predict 277 protein coding genes, of which 94 had been sequenced already in the course of studying the biology of their gene products, and examples of 12 different transposable elements. We show that an interval between bands 3A2 and 3C2, believed in the 1970s to show a correlation between the number of bands on the polytene chromosomes and the 20 genes identified by conventional genetics, is predicted to contain 45 genes from its DNA sequence. We have determined the insertion sites of P-elements from 111 mutant lines, about half of which are in a position likely to affect the expression of novel predicted genes, thus representing a resource for subsequent functional genomic analysis. We compare the European Drosophila Genome Project sequence with the corresponding part of the independently assembled and annotated Joint Sequence determined through "shotgun" sequencing. Discounting differences in the distribution of known transposable elements between the strains sequenced in the two projects, we detected three major sequence differences, two of which are probably explained by errors in assembly; the origin of the third major difference is unclear. In addition there are eight sequence gaps within the Joint Sequence. At least six of these eight gaps are likely to be sites of transposable elements; the other two are complex. Of the 275 genes in common to both projects, 60% are identical within 1% of their predicted amino-acid sequence and 31% show minor differences such as in choice of translation initiation or termination codons; the remaining 9% show major differences in interpretation.
Assuntos
Proteínas de Drosophila , Drosophila melanogaster/genética , Genes de Insetos/genética , Análise de Sequência de DNA/métodos , Cromossomo X/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Biologia Computacional , Elementos de DNA Transponíveis/genética , Proteínas de Ligação a DNA/genética , Feminino , Ordem dos Genes/genética , Masculino , Dados de Sequência Molecular , Mapeamento Físico do Cromossomo/métodos , Fatores de Transcrição/genéticaRESUMO
One of the rewards of having a Drosophila melanogaster whole-genome sequence will be the potential to understand the molecular bases for structural features of chromosomes that have been a long-standing puzzle. Analysis of 2.6 megabases of sequence from the tip of the X chromosome of Drosophila identifies 273 genes. Cloned DNAs from the characteristic bulbous structure at the tip of the X chromosome in the region of the broad complex display an unusual pattern of in situ hybridization. Sequence analysis revealed that this region comprises 154 kilobases of DNA flanked by 1.2-kilobases of inverted repeats, each composed of a 350-base pair satellite related element. Thus, some aspects of chromosome structure appear to be revealed directly within the DNA sequence itself.
Assuntos
Drosophila melanogaster/genética , Cromossomo X/genética , Animais , Bandeamento Cromossômico , Biologia Computacional , Cosmídeos , Elementos de DNA Transponíveis , DNA Satélite , Genes de Insetos , Hibridização In Situ , Sequências Repetitivas de Ácido Nucleico , Análise de Sequência de DNA , Cromossomo X/ultraestruturaRESUMO
We describe here the construction of six deletion mutants and their basic phenotypic analysis. Six open reading frames (ORFs) from chromosome X, YJR039w, YJR041c, YJR043c, YJR046w, YJR053w and YJR065c, were disrupted by deletion cassettes with long (LFH) or short (SFH) flanking regions homologous to the target locus. The LFH deletion cassette was made by introducing into the kanMX4 marker module two polymerase chain reaction (PCR) fragments several hundred base pairs (bp) in size homologous to the promoter and terminator regions of a given ORF. The SFH gene disruption construct was obtained by PCR amplification of the kanMX4 marker with primers providing homology to the target gene. The region of homology to mediate homologous recombination was about 70 bp. Sporulation and tetrad analysis revealed that ORFs YJR041c, YJR046w and YJR065c are essential genes. Complementation tests by corresponding cognate gene clones confirmed this observation. The non-growing haploid segregants were observed under the microscope. The yjr041c delta haploid cells gave rise to microcolonies comprising about 20 to 50 cells. Most yjr046w delta cells were blocked after one or two cell cycles with heterogeneous bud sizes. The yjr065c delta cells displayed an unbudded spore or were arrested before completion of the first cell division cycle with a bud of variable size. The deduced protein of ORF YJR065c, that we named Act4, belongs to the Arp3 family of actin-related proteins. Three other ORFs, YJR039w, YJR043c and YJR053w are non-essential genes. The yjr043c delta cells hardly grew at 15 degrees C, indicating that this gene is required for growth at low temperature. Complementation tests confirmed that the disruption of YJR043c is responsible for this growth defect. In addition, the mating efficiency of yjr043c delta and yjr053w delta cells appear to be moderately affected.
