Genone-wide mutation dynamic within a long-lived individual of Armillaria
J. B. ANDERSON (1). (1) University of Toronto, Missisauga, ON, Canada
Mutation is the ultimate source of all genetic variation in populations and yet the events themselves remain unobservable and buried in the past. Long-lived individuals of <i>Armillaria gallica</i>, a common opportunistic fungal pathogen of tree roots in temperate forests of the northern hemisphere, provide a spatial context for the mutational dynamic. Each individual of <i>A. gallica</i> arises in a single mating event between two haploid gametes and the resulting diploid of unique genotype then grows vegetatively to occupy a discrete spatial territory including many adjacent tree root systems. In effect, this leaves a spatial record of growth over time within which mutations can be pinpointed. To identify mutations, the entire genomes of three spatially separated samples of one individual of <i>A. gallica</i> approximately 200 by 60 m in size were sequenced and compared. In this comparison, mutations and regions of loss of heterozygosity (LOH) were identified and then assayed in another 22 isolates from the same individual.by conventional PCR and Sanger sequencing. The genotype network of all mutations and LOH events was without internal conflict. Further, the spatial pattern of genotypes was non-random and appeared to reflect the vegetative expansion leading to the present-day individual. I will discuss the implications of the whole-genome data in estimating mutation rates and cellular generation times.
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