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941.
The cost of inbreeding in Arabidopsis 总被引:16,自引:0,他引:16
Population geneticists have long sought to estimate the distribution of selection intensities among genes of diverse function across the genome. Only recently have DNA sequencing and analytical techniques converged to make this possible. Important advances have come from comparing genetic variation within species (polymorphism) with fixed differences between species (divergence). These approaches have been used to examine individual genes for evidence of selection. Here we use the fact that the time since species divergence allows combination of data across genes. In a comparison of amino-acid replacements among species of the mustard weed Arabidopsis with those among species of the fruitfly Drosophila, we find evidence for predominantly beneficial gene substitutions in Drosophila but predominantly detrimental substitutions in Arabidopsis. We attribute this difference to the Arabidopsis mating system of partial self-fertilization, which corroborates a prediction of population genetics theory that species with a high frequency of inbreeding are less efficient in eliminating deleterious mutations owing to their reduced effective population size. 相似文献
942.
Bentley SD Chater KF Cerdeño-Tárraga AM Challis GL Thomson NR James KD Harris DE Quail MA Kieser H Harper D Bateman A Brown S Chandra G Chen CW Collins M Cronin A Fraser A Goble A Hidalgo J Hornsby T Howarth S Huang CH Kieser T Larke L Murphy L Oliver K O'Neil S Rabbinowitsch E Rajandream MA Rutherford K Rutter S Seeger K Saunders D Sharp S Squares R Squares S Taylor K Warren T Wietzorrek A Woodward J Barrell BG Parkhill J Hopwood DA 《Nature》2002,417(6885):141-147
Streptomyces coelicolor is a representative of the group of soil-dwelling, filamentous bacteria responsible for producing most natural antibiotics used in human and veterinary medicine. Here we report the 8,667,507 base pair linear chromosome of this organism, containing the largest number of genes so far discovered in a bacterium. The 7,825 predicted genes include more than 20 clusters coding for known or predicted secondary metabolites. The genome contains an unprecedented proportion of regulatory genes, predominantly those likely to be involved in responses to external stimuli and stresses, and many duplicated gene sets that may represent 'tissue-specific' isoforms operating in different phases of colonial development, a unique situation for a bacterium. An ancient synteny was revealed between the central 'core' of the chromosome and the whole chromosome of pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae. The genome sequence will greatly increase our understanding of microbial life in the soil as well as aiding the generation of new drug candidates by genetic engineering. 相似文献
943.
Computational and evolutionary aspects of language 总被引:11,自引:0,他引:11
944.
945.
DiGeorge syndrome phenotype in mice mutant for the T-box gene, Tbx1 总被引:17,自引:0,他引:17
946.
Bejaoui K Wu C Scheffler MD Haan G Ashby P Wu L de Jong P Brown RH 《Nature genetics》2001,27(3):261-262
Hereditary sensory neuropathy type 1 (HSN1, MIM 162400; ref. 1) genetically maps to human chromosome 9q22 (refs. 2-4). We report here that the gene encoding a subunit of serine palmitoyltransferase is located within the HSN1 locus, expressed in dorsal root ganglia (DRG) and mutated in HSN1. 相似文献
947.
Boyartchuk VL Broman KW Mosher RE D'Orazio SE Starnbach MN Dietrich WF 《Nature genetics》2001,27(3):259-260
We have used a novel quantitative trait locus model to study the genetics of survival of F2 progeny of susceptible BALB/cByJ and resistant C57BL/6ByJ mice that have been infected with Listeria monocytogenes. This allowed us to map modifiers of L. monocytogenes susceptibility to chromosomes 5 and 13. 相似文献
948.
Embryonic stem cells offer unprecedented opportunities for random or targeted genome alterations in the mouse. We present here an efficient strategy to create chromosome-specific loss of heterozygosity in embryonic stem cells. The combination of this method with genome-wide mutagenesis in ES cells (using chemical mutagens or gene-trap vectors) opens up the possibility for in vitro or in vivo functional screening of recessive mutations in the mouse. 相似文献
949.
Failure to confirm NOTCH4 association with schizophrenia in a large population-based sample from Scotland 总被引:1,自引:0,他引:1
McGinnis RE Fox H Yates P Cameron LA Barnes MR Gray IC Spurr NK Hurko O St Clair D 《Nature genetics》2001,28(2):128-129
The NOTCH4 gene was recently reported to be associated with schizophrenia based on TDT analysis of 80 British trios. The strongest evidence for association derived from two microsatellites. We genotyped both loci in a large sample of unrelated Scottish schizophrenics and controls, but failed to replicate the reported association, finding instead that each putative schizophrenia-associated allele had a somewhat lower frequency in schizophrenics than in controls. 相似文献
950.