title: Origins of multicellular evolvability in snowflake yeast.
abstract: Complex life has arisen through a series of 'major transitions' in which collectives of formerly autonomous individuals evolve into a single, integrated organism. A key step in this process is the origin of higher-level evolvability, but little is known about how higher-level entities originate and gain the capacity to evolve as an individual. Here we report a single mutation that not only creates a new level of biological organization, but also potentiates higher-level evolvability. Disrupting the transcription factor ACE2 in Saccharomyces cerevisiae prevents mother-daughter cell separation, generating multicellular 'snowflake' yeast. Snowflake yeast develop through deterministic rules that produce geometrically defined clusters that preclude genetic conflict and display a high broad-sense heritability for multicellular traits; as a result they are preadapted to multicellular adaptation. This work demonstrates that simple microevolutionary changes can have profound macroevolutionary consequences, and suggests that the formation of clonally developing clusters may often be the first step to multicellularity.
authors.affiliation: School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0230, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Ratcliff
authors.affiliation: Plant Biology, University of Minnesota, St Paul, Minnesota 55108, USA.
authors.forename: Johnathon D
authors.initials: JD
authors.lastname: Fankhauser
authors.affiliation: Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany.
authors.forename: David W
authors.initials: DW
authors.lastname: Rogers
authors.affiliation: 1] Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany [2] Department of Genetics, Evolution, and Environment, University College London, London WC1N 6BT, UK.
authors.forename: Duncan
authors.initials: D
authors.lastname: Greig
authors.affiliation: 1] Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, Minnesota 55108, USA [2] The BioTechnology Institute, University of Minnesota, St Paul, Minnesota 55108, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Travisano
mesh_terms: D000085962:Angiotensin-Converting Enzyme 2; D009154:Mutation; D007703:Peptidyl-Dipeptidase A / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics* / Q000502:physiology
chemical_list: D007703:Peptidyl-Dipeptidase A; D000085962:Angiotensin-Converting Enzyme 2