title: Nuclear dynamics in a fungal chimera.
abstract: A fungal colony is a syncytium composed of a branched and interconnected network of cells. Chimerism endows colonies with increased virulence and ability to exploit nutritionally complex substrates. Moreover, chimera formation may be a driver for diversification at the species level by allowing lateral gene transfer between strains that are too distantly related to hybridize sexually. However, the processes by which genomic diversity develops and is maintained within a single colony are little understood. In particular, both theory and experiments show that genetically diverse colonies may be unstable and spontaneously segregate into genetically homogenous sectors. By directly measuring patterns of nuclear movement in the model ascomycete fungus Neurospora crassa, we show that genetic diversity is maintained by complex mixing flows of nuclei at all length scales within the hyphal network. Mathematical modeling and experiments in a morphological mutant reveal some of the exquisite hydraulic engineering necessary to create the mixing flows. In addition to illuminating multinucleate and multigenomic lifestyles, the adaptation of a hyphal network for mixing nuclear material provides a previously unexamined organizing principle for understanding morphological diversity in the more-than-a-million species of filamentous fungi.
authors.affiliation: Department of Mathematics, University of California, Los Angeles, CA 90095, USA. mroper@math.ucla.edu
authors.forename: Marcus
authors.initials: M
authors.lastname: Roper
authors.forename: Anna
authors.initials: A
authors.lastname: Simonin
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Hickey
authors.forename: Abby
authors.initials: A
authors.lastname: Leeder
authors.forename: N Louise
authors.initials: NL
authors.lastname: Glass
mesh_terms: D000465:Algorithms; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002468:Cell Physiological Phenomena; D003593:Cytoplasm / Q000378:metabolism / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism; D025301:Hyphae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008954:Models, Biological; D009492:Neurospora crassa / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D005656:Fungal Proteins; D006657:Histones; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins
keywords: biological networks; heterokaryon; hydrodynamics