Biological techniques articles within Nature

Featured

  • Letter |

    An extensive genome-wide survey of over 48,000 single nucleotide polymorphisms in dogs and their wild progenitor, the grey wolf, was conducted to shed light on the process of dog diversification. The results reveal that much of genome diversity came from Middle Eastern progenitors, combined with interbreeding with local wolf populations, and that recent evolution involved limited genetic variation to create the phenotypic diversity of modern dogs.

    • Bridgett M. vonHoldt
    • , John P. Pollinger
    •  & Robert K. Wayne
  • Letter |

    Variation in the regulation of gene transcription between individuals is thought to be a major cause of phenotypic diversity. Here, individual differences in the binding of transcription-factor proteins are studied. A well-known transcription factor in the yeast pheromone pathway is used as an example, and the underlying genetic loci responsible for variation in its binding are mapped. The study reveals new insights into the mechanisms of gene regulation, and new regulators of the yeast pheromone pathway.

    • Wei Zheng
    • , Hongyu Zhao
    •  & Michael Snyder
  • Letter
    | Open Access

    The freshwater cnidarian Hydra is a significant model for studies of axial patterning, stem cell biology and regeneration. Its (A+T)-rich genome has now been sequenced. Comparison of this genome with those of other animals provides insights into the evolution of epithelia, contractile tissues, developmentally regulated transcription factors, pluripotency genes and more.

    • Jarrod A. Chapman
    • , Ewen F. Kirkness
    •  & Robert E. Steele
  • Article |

    Snakes are notoriously apt at generating 'thermal images' of predators or prey. The underlying physiology has been unclear, although in snakes such as pythons, vipers and boas, infrared signals are initially received by the pit organ. Here it is shown that pit-bearing snakes rely on heat detection by the ion channel TRPA1. This extends the sensory repertoire of the TRPA1 family of proteins, which detect chemical irritants in mammals and thermal variations in insects.

    • Elena O. Gracheva
    • , Nicholas T. Ingolia
    •  & David Julius
  • Letter |

    A genome-wide RNA interference screen to systematically test the genetic basis for formation and function of the Drosophila muscle is described. A role in muscle for 2,785 genes is identified; many of these genes are phylogenetically conserved.

    • Frank Schnorrer
    • , Cornelia Schönbauer
    •  & Barry J. Dickson
  • Article |

    In mammals, embryos are considered to be sexually indifferent until the action of a sex-determining gene initiates gonadal differentiation. Here it is demonstrated that this situation is different for birds. Using rare, naturally occurring chimaeric chickens where one side of the animal appears male and the other female, it is shown that avian somatic cells possess an inherent sex identity and that, in birds, sexual differentiation is cell autonomous.

    • D. Zhao
    • , D. McBride
    •  & M. Clinton
  • Letter
    | Open Access

    Here, the genomes of birds representing eight populations of domestic chickens are compared with the genome of their wild ancestor, the red jungle fowl. The results reveal selective sweeps of favourable alleles and mutations that may have contributed to domestication. One selective sweep, for instance, occurred at the locus encoding the thyroid stimulating hormone receptor, which is important in metabolism and in the timing of vertebrate reproduction.

    • Carl-Johan Rubin
    • , Michael C. Zody
    •  & Leif Andersson
  • Letter |

    Female gametes in flowering plants develop from a meiotic division of a precursor cell followed by mitotic divisions of one of the resulting haploid cells to yield the gametophyte. Here, ARGONAUTE 9 (AGO9) — a protein involved in RNA interference — is identified as a factor required for specification of the gametophyte. AGO9 is found not in the cell destined to be the gametophyte, but in the neighbouring companion cells, suggesting that it functions in a non-cell-autonomous manner.

    • Vianey Olmedo-Monfil
    • , Noé Durán-Figueroa
    •  & Jean-Philippe Vielle-Calzada
  • News & Views |

    A neat mode of operation of the atomic force microscope has been used to probe the interface between mica and water. The results help to settle a long-standing debate about the nature of this interface.

    • Joost W. M. Frenken
    •  & Tjerk H. Oosterkamp
  • Article |

    A new strategy is presented to accurately profile the activity of human genes in endocytosis by combining genome-wide RNAi, automated high-resolution confocal microscopy and quantitative multi-parametric image analysis. Several novel components of endocytosis and endosome trafficking were uncovered; a systems analysis further revealed that the cell regulates the number, size and concentration of cargo within endosomes.

    • Claudio Collinet
    • , Martin Stöter
    •  & Marino Zerial
  • Letter |

    The existence of all-female species of whiptail lizard, formed as a hybrid between sexual species, has been known since 1962; however, how the meiotic program is altered to produce diploid eggs while maintaining heterozygosity has remained unclear. Here it is shown in parthenogenetic species that meiosis initiates with twice the number of chromosomes compared to sexual species, and that pairing and recombination takes place between genetically identical sister chromosomes instead of between homologues.

    • Aracely A. Lutes
    • , William B. Neaves
    •  & Peter Baumann
  • Technology Feature |

    As the techniques for imaging whole animals become more sophisticated, researchers are able to get a clearer picture of what is going on inside. Monya Baker looks at the options available.

    • Monya Baker
  • Letter |

    One of two papers showing the generation of haematopoietic stem cells (HSCs) from the ventral wall of the dorsal aorta in live zebrafish embryos. Here, combined fluorescent reporter transgenes, confocal time-lapse microscopy and flow cytometry identify and isolate the stepwise intermediates as aortic haemogenic endothelium transitions to nascent HSCs. HSCs generated from this haemogenic endothelium are the lineal founders of virtually all of the adult haematopoietic system.

    • Julien Y. Bertrand
    • , Neil C. Chi
    •  & David Traver
  • Letter |

    De novo emergence of phenotypically defined haematopoietic stem cells (Sca1+, c kit+, CD41+) directly from ventral aortic haemogenic endothelial cells is shown in mice. Although the study did not visualize live embryos, it instead developed a dissection procedure to visualize the deeply located aorta.

    • Jean-Charles Boisset
    • , Wiggert van Cappellen
    •  & Catherine Robin
  • Article |

    Insect vectors of diseases locate their animal hosts through olfaction via largely unknown molecular processes. Here the 'empty neuron' system of genetically engineered Drosophila is used to assign specific odorants to the entire repertoire of olfactory receptors of the malaria vector Anopheles gambiae. The results illuminate ecological and neurobiological differences between mosquitoes and fruitflies and provide new potential molecular targets to boost the struggle against insect–borne diseases.

    • Allison F. Carey
    • , Guirong Wang
    •  & John R. Carlson
  • Letter |

    Mammals are repelled by large concentrations of salts but attracted to low concentrations of sodium. In mice, the latter behaviour can be blocked by the ion channel inhibitor amiloride. Here, mice have been produced lacking the drug's target sodium channel, ENaC, specifically in taste receptor neurons. It is confirmed that sodium sensing, like the four other taste modalities (sweet, sour, bitter and umami), is mediated by a dedicated 'labelled line'.

    • Jayaram Chandrashekar
    • , Christina Kuhn
    •  & Charles S. Zuker
  • Letter |

    Although cyclin D1 is frequently overexpressed in human cancers, the full range of its functions in normal development and oncogenesis is unclear. Here, tagged cyclin D1 knock-in mouse strains are developed to allow a search for cyclin D1-binding proteins in different mouse organs using high-throughput mass spectrometry. The results show that, in addition to its established cell cycle roles, cyclin D1 has an in vivo transcriptional function in mouse development.

    • Frédéric Bienvenu
    • , Siwanon Jirawatnotai
    •  & Piotr Sicinski
  • News Feature |

    Can engineering approaches tame the complexity of living systems? Roberta Kwok explores five challenges for the field and how they might be resolved.

    • Roberta Kwok
  • Letter |

    High mutation rates in the influenza A virus facilitate the generation of viral escape mutants, rendering vaccines and drugs potentially ineffective, but targeting host cell determinants could prevent viral escape. Here, 287 human host cell genes influencing influenza A virus replication are found using a genome-wide RNA interference screen. An independent assay is then used to investigate overlap between genes necessary for different viral strains.

    • Alexander Karlas
    • , Nikolaus Machuy
    •  & Thomas F. Meyer
  • Letter |

    If the activity of genetically specified neurons is silenced in a temporally precise fashion, the roles of different cell classes in neural processes can be studied. Members of the class of light-driven outward proton pumps are now shown to mediate powerful, safe, multiple-colour silencing of neural activity. The gene archaerhodopsin-3 (Arch) enables near 100% silencing of neurons in the awake brain when virally expressed in the mouse cortex and illuminated with yellow light.

    • Brian Y. Chow
    • , Xue Han
    •  & Edward S. Boyden