Title page for ETD etd-10242005-124126


Type of Document Dissertation
Author Flynn, Timothy M.
URN etd-10242005-124126
Title Evolutionary biology of the Armillaria mellea species complex
Degree PhD
Department Botany
Advisory Committee
Advisor Name Title
Falkinham, Joseph O. III Committee Co-Chair
Vilgalys, Rytas J. Committee Co-Chair
Johnson, John S. Committee Member
Niehaus, Walter G. Jr. Committee Member
Stipes, R. Jay Committee Member
West, David A. Committee Member
Keywords
  • Armillaria mellea
Date of Defense 1994-12-15
Availability restricted
Abstract

DNA-DNA hybridization experiments were used to examine the genetic variation that has accumulated with the North American Biological Species (NABS) of Armillaria. Forty strains including nine of the ten NABS and A. tabescens were used in this study. The normalized percent hybridization values ranged from 80%-100% similarity within a given biological species and ranged from 30%-85% among the biological species, The NPH data was summarized with UPGMA clustering analysis to give four main clustering groups, two were homogeneous and two were heterogeneous, The first included A. tabescens; the second included A. mellea; the third included A. calvescens, A. gallica, A. sinapina, NABS IX, and NABS X; the fourth included A. gemina and A. ostoyae. One cluster of two A. gallica strains shared greater similarity with NABS X than it had to four other conspecific strains, The NPH data and estimates of genome size (genetic complexity) was analyzed using a stoichiometric approach to calculate equivalents of homologous DNA and low copy repetition frequencies. Reciprocal NPH values did not predict relative genome size as expected, However, as the relative genome size increases, the equivalents of homologous DNA increases in the same proportion. This suggests that as an Armillaria genome increases in total complexity (novel sequences), certain ancestral sequences are duplicated in proportion the increase in total genetic complexity, This interpretation of the data is discussed with respect to interspecific hybridization, diploidy, and chromosomal evolution including alloploidy, aneuploidy, and chromosomal length polymorphisms.

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