Genetics back issues from August 2007:
What Did Sutton See?: Thirty Years of Confusion Over the Chromosomal Basis of Mendelism
Aug 01, 2007; ... IN December 1902, 2 years after the rediscovery of Mendel's 1865 article, America's leading cytologist, Edmund Beecher Wilson, announced to the readers of Science that a graduate student of his at Columbia University had discovered the physical basis of the "Mendelian principle," by which Wilson ...
Cytotype Regulation by Telomeric P Elements in Drosophila melanogaster: Evidence for Involvement of an RNA Interference Gene
Aug 01, 2007; ... ABSTRACT P elements inserted at the left telomere of the X chromosome evoke the P cytotype, a maternally inherited condition that regulates the P-element family in the Drosophila germline. This regulation is completely disrupted in stocks heterozygous for mutations in aubergine, a gene ...
Cytotype Regulation by Telomeric P Elements in Drosophila melanogaster: Interactions With P Elements From M' Strains
Aug 01, 2007; ... ABSTRACT P strains of Drosophila are distinguished from M strains by having P elements in their genomes and also by having the P cytotype, a maternally inherited condition that strongly represses P-element-induced hybrid dysgenesis. The P cytotype is associated with P elements inserted ...
A Maternal Screen for Genes Regulating Drosophila Oocyte Polarity Uncovers New Steps in Meiotic Progression
Aug 01, 2007; ... ABSTRACT Meiotic checkpoints monitor chromosome status to ensure correct homologous recombination, genomic integrity, and chromosome segregation. In Drosophila, the persistent presence of double-strand DNA breaks (DSB) activates the ATR/Mei-41 checkpoint, delays progression through ...
Multiple Functions of Drosophila BLM Helicase in Maintenance of Genome Stability
Aug 01, 2007; ... ABSTRACT Bloom Syndrome, a rare human disorder characterized by genomic instability and predisposition to cancer, is caused by mutation of BLM, which encodes a RecQ-family DNA helicase. The Drosophila melanogaster ortholog of BLM, DmBlm, is encoded by mus309. Mutations in mus309 cause ...
Synthetic Lethality of Drosophila in the Absence of the MUS81 Endonuclease and the DmBlm Helicase Is Associated With Elevated Apoptosis
Aug 01, 2007; ... ABSTRACT Mus81-Mms4 (Mus81-Eme1 in some species) is a heterodimeric DNA structure-specific endonuclease that has been implicated in meiotic recombination and processing of damaged replication forks in fungi. We generated and characterized mutations in Drosophila melanogaster mus81 and ...
Saccharomyces cerevisiae Sae2- and Tel1-Dependent Single-Strand DNA Formation at DNA Break Promotes Microhomology-Mediated End Joining
Aug 01, 2007; ... ABSTRACT Microhomology-mediated end joining (MMEJ) joins DNA ends via short stretches [5-20 nucleotides (nt)] of direct repeat sequences, yielding deletions of intervening sequences. Non-homologous end joining (NHEJ) and single-strand annealing (SSA) are other error prone processes that ...
SYP-3 Restricts Synaptonemal Complex Assembly to Bridge Paired Chromosome Axes During Meiosis in Caenorhabditis elegans
Aug 01, 2007; ... ABSTRACT Synaptonemal complex (SC) formation must be regulated to occur only between aligned pairs of homologous chromosomes, ultimately ensuring proper chromosome segregation in meiosis. Here we identify SYP-3, a coiled-coil protein that is required for assembly of the central region of ...
Synapsis-Defective Mutants Reveal a Correlation Between Chromosome Conformation and the Mode of Double-Strand Break Repair During Caenorhabditis elegans Meiosis
Aug 01, 2007; ... ABSTRACT SYP-3 is a new structural component of the synaptonemal complex (SC) required for the regulation of chromosome synapsis. Both chromosome morphogenesis and nuclear organization are altered throughout the germlines of syp-3 mutants. Here, our analysis of syp-3 mutants provides ...
Predicting the Size of the Progeny Mapping Population Required to Positionally Clone a Gene
Aug 01, 2007; ... ABSTRACT A key frustration during positional gene cloning (map-based cloning) is that the size of the progeny mapping population is difficult to predict, because the meiotic recombination frequency varies along chromosomes. We describe a detailed methodology to improve this prediction ...
Phenotypic and Transcriptomic Changes Associated With Potato Autopolyploidization
Aug 01, 2007; ... ABSTRACT Polyploidy is remarkably common in the plant kingdom and polyploidization is a major driving force for plant genome evolution. Polyploids may contain genomes from different parental species (allopolyploidy) or include multiple sets of the same genome (autopolyploidy). Genetic ...
Using Reporter Gene Assays to Identify cis Regulatory Differences Between Humans and Chimpanzees
Aug 01, 2007; ... ABSTRACT Most phenotypic differences between human and chimpanzee are likely to result from differences in gene regulation, rather than changes to protein-coding regions. To date, however, only a handful of human-chimpanzee nucleotide differences leading to changes in gene regulation ...
Silencing of the Aflatoxin Gene Cluster in a Diploid Strain of Aspergillus flavus Is Suppressed by Ectopic aflR Expression
Aug 01, 2007; ... ABSTRACT Aflatoxins are toxic secondary metabolites produced by a 70-kb cluster of genes in Aspergillus flavus. The cluster genes are coordinately regulated and reside as a single copy within the genome. Diploids between a wild-type strain and a mutant (649) lacking the aflatoxin gene ...
Dal81 Enhances Stp1- and Stp2-Dependent Transcription Necessitating Negative Modulation by Inner Nuclear Membrane Protein Asi1 in Saccharomyces cerevisiae
Aug 01, 2007; ... ABSTRACT The yeast transcription factors Stp1 and Stp2 are synthesized as latent cytoplasmic precursors. In response to extracellular amino acids, the plasma membrane SPS sensor endoproteolytically excises the N-terminal domains that mediate cytoplasmic retention, enabling the processed ...
A Genetic Screen Identifies Novel Polycomb Group Genes in Drosophila
Aug 01, 2007; ... ABSTRACT Polycomb group (PcG) genes encode evolutionarily conserved transcriptional repressors that are required for the long-term silencing of particular developmental control genes in animals and plants. PcG genes were first identified in Drosophila as regulators that keep HOX genes ...
Genetic Screens for Caenorhabditis elegans Mutants Defective in Left/Right Asymmetric Neuronal Fate Specification
Aug 01, 2007; ... ABSTRACT We describe here the results of genetic screens for Caenorhabditis elegans mutants in which a single neuronal fate decision is inappropriately executed. In wild-type animals, the two morphologically bilaterally symmetric gustatory neurons ASE left (ASEL) and ASE right (ASER) ...
Predicting and Testing Physical Locations of Genetically Mapped Loci on Tomato Pachytene Chromosome 1
Aug 01, 2007; ... ABSTRACT Predicting the chromosomal location of mapped markers has been difficult because linkage maps do not reveal differences in crossover frequencies along the physical structure of chromosomes. Here we combine a physical crossover map based on the distribution of recombination ...
Efficient Tor Signaling Requires a Functional Class C Vps Protein Complex in Saccharomyces cerevisiae
Aug 01, 2007; ... ABSTRACT The Tor kinases regulate responses to nutrients and control cell growth. Unlike most organisms that only contain one Tor protein, Saccharomyces cerevisiae expresses two, Tor1 and Tor2, which are thought to share all of the rapamycin-sensitive functions attributable to Tor ...
A Genetic Analysis of the Drosophila mcm5 Gene Defines a Domain Specifically Required for Meiotic Recombination
Aug 01, 2007; ... ABSTRACT Members of the minichromosome maintenance (MCM) family have pivotal roles in many biological processes. Although originally studied for their role in DNA replication, it is becoming increasingly apparent that certain members of this family are multifunctional and also play roles ...
Genetic Analysis of the Histidine Utilization (hut) Genes in Pseudomonas fluorescens SBW25
Aug 01, 2007; ... ABSTRACT The histidine utilization (hut) locus of Pseudomonas fluorescens SBW25 confers the ability to utilize histidine as a sole carbon and nitrogen source. Genetic analysis using a combination of site-directed mutagenesis and chromosomally integrated lacZ fusions showed the hut locus ...
A Genetic Mosaic Analysis With a Repressible Cell Marker Screen to Identify Genes Involved in Tracheal Cell Migration During Drosophila Air Sac Morphogenesis
Aug 01, 2007; ... ABSTRACT Branching morphogenesis of the Drosophila tracheal system relies on the fibroblast growth factor receptor (FGFR) signaling pathway. The Drosophila FGF ligand Branchless (Bnl) and the FGFR Breathless (Btl/FGFR) are required for cell migration during the establishment of the ...
Unraveling the Genetic Complexity of Drosophila stardust During Photoreceptor Morphogenesis and Prevention of Light-Induced Degeneration
Aug 01, 2007; ... ABSTRACT Drosophila Stardust, a membrane-associated guanylate kinase (MAGUK), recruits the transmembrane protein Crumbs and the cytoplasmic proteins DPATJ and DLin-7 into an apically localized protein scaffold. This evolutionarily conserved complex is required for epithelial cell ...
A Rho-Binding Protein Kinase C-Like Activity Is Required for the Function of Protein Kinase N in Drosophila Development
Aug 01, 2007; ... ABSTRACT The Rho GTPases interact with multiple downstream effectors to exert their biological functions, which include important roles in tissue morphogenesis during the development of multicellular organisms. Among the Rho effectors are the protein kinase N (PKN) proteins, which are ...
The Molecular Chaperone Hsp90 Is Required for mRNA Localization in Drosophila melanogaster Embryos
Aug 01, 2007; ... ABSTRACT Localization of maternal nanos mRNA to the posterior pole is essential for development of both the abdominal segments and primordial germ cells in the Drosophila embryo. Unlike maternal mRNAs such as bicoid and oskar that are localized by directed transport along microtubules, ...
The flare Gene, Which Encodes the AIP1 Protein of Drosophila, Functions to Regulate F-Actin Disassembly in Pupal Epidermal Cells
Aug 01, 2007; ... ABSTRACT Adult Drosophila are decorated with several types of polarized cuticular structures, such as hairs and bristles. The morphogenesis of these takes place in pupal cells and is mediated by the actin and microtubule cytoskeletons. Mutations in flare (flr) result in grossly abnormal ...
Regulation of Axon Guidance by Slit and Netrin Signaling in the Drosophila Ventral Nerve Cord
Aug 01, 2007; ... ABSTRACT Netrin and Slit signaling systems play opposing roles during the positioning of longitudinal tracts along the midline in the ventral nerve cord of Drosophila embryo. It has been hypothesized that a gradient of Slit from the midline interacts with three different Robo receptors ...
The Bro1-Domain Protein, EGO-2, Promotes Notch Signaling in Caenorhabditis elegans
Aug 01, 2007; ... ABSTRACT In Caenorhabditis elegans, as in other animals, Notch-type signaling mediates numerous inductive events during development. The mechanism of Notch-type signaling involves proteolytic cleavage of the receptor and subsequent transport of the receptor intracellular domain to the ...
A Clonal Genetic Screen for Mutants Causing Defects in Larval Tracheal Morphogenesis in Drosophila
Aug 01, 2007; ... ABSTRACT The initial establishment of the tracheal network in the Drosophila embryo is beginning to be understood in great detail, both in its genetic control cascades and in its cell biological events. By contrast, the vast expansion of the system during larval growth, with its ...
Patterns of Molecular Variation and Evolution in Drosophila americana and Its Relatives
Aug 01, 2007; ... ABSTRACT We present the results of a survey of DNA sequence variability at X-linked and autosomal loci in Drosophila americana and of patterns of DNA sequence evolution among D. americana and four other related species in the virilis group of Drosophila. D. americana shows a typical ...
Prediction of Multilocus Identity-by-Descent
Aug 01, 2007; ... ABSTRACT Previous studies have enabled exact prediction of probabilities of identity-by-descent (IBD) in randommating populations for a few loci (up to four or so), with extension to more using approximate regression methods. Here we present a precise predictor of multiple-locus IBD ...
Intraspecific Genetic Variations, Fitness Cost and Benefit of RPW8, A Disease Resistance Locus in Arabidopsis thaliana
Aug 01, 2007; ... ABSTRACT The RPW8 locus of Arabidopsis thaliana confers broad-spectrum resistance to powdery mildew pathogens. In many A. thaliana accessions, this locus contains two homologous genes, RPW8.1 and RPW8.2. In some susceptible accessions, however, these two genes are replaced by HR4, a ...
Incorporating Experimental Design and Error Into Coalescent/Mutation Models of Population History
Aug 01, 2007; ... ABSTRACT Coalescent theory provides a powerful framework for estimating the evolutionary, demographic, and genetic parameters of a population from a small sample of individuals. Current coalescent models have largely focused on population genetic factors (e.g., mutation, population ...
Molecular Differentiation at Nuclear Loci in French Host Races of the European Corn Borer (Ostrinia nubilalis)
Aug 01, 2007; ... ABSTRACT French populations of the European corn borer consist of two sympatric and genetically differentiated host races. As such, they are well suited to study processes that could be involved in sympatric speciation, but the initial conditions of host-race divergence need to be ...
Linkage Disequilibrium and Recombination Rate Estimates in the Self-Incompatibility Region of Arabidopsis lyrata
Aug 01, 2007; ... ABSTRACT Genetic diversity is unusually high at loci in the S-locus region of the self-incompatible species of the flowering plant, Arabidopsis lyrata, not just in the S loci themselves, but also at two nearby loci. In a previous study of a single natural population from Iceland, we ...
On the Utility of Linkage Disequilibrium as a Statistic for Identifying Targets of Positive Selection in Nonequilibrium Populations
Aug 01, 2007; ... ABSTRACT A critically important challenge in empirical population genetics is distinguishing neutral nonequilibrium processes from selective forces that produce similar patterns of variation. We here examine the extent to which linkage disequilibrium (i.e., nonrandom associations between ...
A Fitness Cost Associated With the Antibiotic Resistance Enzyme SME-1 ß-Lactamase
Aug 01, 2007; ... ABSTRACT The bla^sub TEM-1^ β-lactamase gene has become widespread due to the selective pressure of β-lactam use and its stable maintenance on transferable DNA elements. In contrast, bla^sub SME-1^ is rarely isolated and is confined to the chromosome of carbapenem-resistant ...
Genome Scan to Detect Genetic Structure and Adaptive Genes of Natural Populations of Cryptomeria japonica
Aug 01, 2007; ... ABSTRACT We investigated 29 natural populations of Cryptomeria japonica using 148 cleaved amplified polymorphic sequence markers to elucidate their genetic structure and identify candidate adaptive genes of this species. In accordance with the inferred evolutionary history of the species ...
A Covariance Structure Model for the Admixture of Binary Genetic Variation
Aug 01, 2007; ... ABSTRACT I derive a covariance structure model for pairwise linkage disequilibrium (LD) between binary markers in a recently admixed population and use a generalized least-squares method to fit the model to two different data sets. Both linked and unlinked marker pairs are incorporated ...
Hybridization in Large-Bodied New World Primates
Aug 01, 2007; ... ABSTRACT Well-documented cases of natural hybridization among primates are not common. In New World primates, natural hybridization has been reported only for small-bodied species, but no genotypic data have ever been gathered that confirm these reports. Here we present genetic evidence ...
Estimating Differential Reproductive Success From Nests of Related Individuals, With Application to a Study of the Mottled Sculpin, Cottus bairdi
Aug 01, 2007; ... ABSTRACT Understanding how variation in reproductive success is related to demography is a critical component in understanding the life history of an organism. Parentage analysis using molecular markers can be used to estimate the reproductive success of different groups of individuals ...
Testing the Extreme Value Domain of Attraction for Distributions of Beneficial Fitness Effects
Aug 01, 2007; ... ABSTRACT In modeling evolutionary genetics, it is often assumed that mutational effects are assigned according to a continuous probability distribution, and multiple distributions have been used with varying degrees of justification. For mutations with beneficial effects, the ...
Rapid Detection of Positive Selection in Genes and Genomes Through Variation Clusters
Aug 01, 2007; ... ABSTRACT Positive selection in genes and genomes can point to the evolutionary basis for differences among species and among races within a species. The detection of positive selection can also help identify functionally important protein regions and thus guide protein engineering. Many ...
Sex-Ratio Evolution in Nuclear-Cytoplasmic Gynodioecy When Restoration Is a Threshold Trait
Aug 01, 2007; ... ABSTRACT Gynodioecious plant species, which have populations consisting of female and hermaphrodite individuals, usually have complex sex determination involving cytoplasmic male sterility (CMS) alleles interacting with nuclear restorers of fertility. In response to recent evidence, we ...
Transposable Element Dynamics of the hAT Element Herves in the Human Malaria Vector Anopheles gambiae s.s.
Aug 01, 2007; ... ABSTRACT Transposable elements are being considered as genetic drive agents for introducing phenotype-altering genes into populations of vectors of human disease. The dynamics of endogenous elements will assist in predicting the behavior of introduced elements. Transposable element ...
A Linkage Map Reveals a Complex Basis for Segregation Distortion in an Interpopulation Cross in the Moss Ceratodon purpureus
Aug 01, 2007; ... ABSTRACT We report the construction of a linkage map for the moss Ceratodon purpureus (n = 13), based on a cross between geographically distant populations, and provide the first experimental confirmation of maternal chloroplast inheritance in bryophytes. From a mapping population of 288 ...
Major Histocompatibility Complex Heterozygosity Reduces Fitness in Experimentally Infected Mice
Aug 01, 2007; ... ABSTRACT It is often suggested that heterozygosity at major histocompatibility complex (MHC) loci confers enhanced resistance to infectious diseases (heterozygote advantage, HA, hypothesis), and overdominant selection should contribute to the evolution of these highly polymorphic genes ....
Concerted Evolution of rDNA in Recently Formed Tragopogon Allotetraploids Is Typically Associated With an Inverse Correlation Between Gene Copy Number and Expression
Aug 01, 2007; ... ABSTRACT We analyzed nuclear ribosomal DNA (rDNA) transcription and chromatin condensation in individuals from several populations of Tragopogon mirus and T. miscellus, allotetraploids that have formed repeatedly within only the last 80 years from T. dubius and T. porrifolius and T ....
Genetic Mapping in the Presence of Genotyping Errors
Aug 01, 2007; ... ABSTRACT Genetic maps are built using the genotypes of many related individuals. Genotyping errors in these data sets can distort genetic maps, especially by inflating the distances. We have extended the traditional likelihood model used for genetic mapping to include the possibility of ...
Bayesian Multiple Quantitative Trait Loci Mapping for Complex Traits Using Markers of the Entire Genome
Aug 01, 2007; ... ABSTRACT A Bayesian methodology has been developed for multiple quantitative trait loci (QTL) mapping of complex binary traits that follow liability threshold models. Unlike most QTL mapping methods where only one or a few markers are used at a time, the proposed method utilizes all ...
The in Silico Map-Based Cloning of Pi36, a Rice Coiled-Coil-Nucleotide-Binding Site-Leucine-Rich Repeat Gene That Confers Race-Specific Resistance to the Blast Fungus
Aug 01, 2007; ... ABSTRACT The indica rice variety Kasalath carries Pi36, a gene that determines resistance to Chinese isolates of rice blast and that has been located to a 17-kb interval on chromosome 8. The genomic sequence of the reference japonica variety Nipponbare was used for an in silico ...
Multipoint Identity-by-Descent Prediction Using Dense Markers to Map Quantitative Trait Loci and Estimate Effective Population Size
Aug 01, 2007; ... ABSTRACT A novel multipoint method, based on an approximate coalescence approach, to analyze multiple linked markers is presented. Unlike other approximate coalescence methods, it considers all markers simultaneously but only two haplotypes at a time.We demonstrate the use of this method ...
New Candidate Genes for Sex-Comb Divergence Between Drosophila mauritiana and Drosophila simulans
Aug 01, 2007; ... ABSTRACT A large-effect QTL for divergence in sex-comb tooth number between Drosophila simulans and D. mauritiana was previously mapped to 73A-84AB. Here we identify genes that are likely contributors to this divergence. We first improved the mapping resolution in the 73A-84AB region ...
Meta-analysis of Polyploid Cotton QTL Shows Unequal Contributions of Subgenomes to a Complex Network of Genes and Gene Clusters Implicated in Lint Fiber Development
Aug 01, 2007; ... ABSTRACT QTL mapping experiments yield heterogeneous results due to the use of different genotypes, environments, and sampling variation. Compilation of QTL mapping results yields a more complete picture of the genetic control of a trait and reveals patterns in organization of trait ...
Quantitative Trait Locus Analysis of the Early Domestication of Sunflower
Aug 01, 2007; ... ABSTRACT Genetic analyses of the domestication syndrome have revealed that domestication-related traits typically have a very similar genetic architecture across most crops, being conditioned by a small number of quantitative trait loci (QTL), each with a relatively large effect on the ...
Epistasis Between Calpain 1 and Its Inhibitor Calpastatin Within Breeds of Cattle
Aug 01, 2007; ... ABSTRACT The calpain gene family and its inhibitors have diverse effects, many related to protein turnover, which appear to affect a range of phenotypes such as diabetes, exercise-induced muscle injury, and pathological events associated with degenerative neural diseases in humans, ...
Fractioned DNA Pooling: A New Cost-Effective Strategy for Fine Mapping of Quantitative Trait Loci
Aug 01, 2007; ... ABSTRACT Selective DNA pooling (SDP) is a cost-effective means for an initial scan for linkage between marker and quantitative trait loci (QTL) in suitable populations. The method is based on scoring marker allele frequencies in DNA pools from the tails of the population trait ...
Multiple-Copy Cluster-Type Organization and Evolution of Genes Encoding O-Methyltransferases in the Apple
Aug 01, 2007; ... ABSTRACT Plant O-methyltransferases (OMTs) play important roles in secondary metabolism. Two clusters of genes coding for caffeic acid OMT (COMT) have been identified in the apple genome. Three genes from one cluster and two genes from another cluster were isolated. These five genes ...
A Dense Single-Nucleotide Polymorphism-Based Genetic Linkage Map of Grapevine (Vitis vinifera L.) Anchoring Pinot Noir Bacterial Artificial Chromosome Contigs
Aug 01, 2007; ... ABSTRACT The construction of a dense genetic map for Vitis vinifera and its anchoring to a BAC-based physical map is described: it includes 994 loci mapped onto 19 linkage groups, corresponding to the basic chromosome number of Vitis. Spanning 1245 cM with an average distance of 1.3 cM ...
Temporal Control of Cell-Specific Transgene Expression in Caenorhabditis elegans
Aug 01, 2007; ... ABSTRACT Cell-specific promoters allow only spatial control of transgene expression in Caenorhabditis elegans. We describe a method, using cell-specific rescue of heat-shock factor-1 (hsf-1) mutants, that allows spatial and temporal regulation of transgene expression. We demonstrate the ...
A Gain-of-Function Screen for Genes That Influence Axon Guidance Identifies the NF-[kappa]B Protein Dorsal and Reveals a Requirement for the Kinase Pelle in Drosophila Photoreceptor Axon Targeting
Aug 01, 2007; ... ABSTRACT To identify novel regulators of nervous system development, we used the GAL4-UAS misexpression system in Drosophila to screen for genes that influence axon guidance in developing embryos. We mobilized the Gene Search (GS) P element and identified 42 lines with insertions in ...