Isozymes of the Isoetes riparia Complex, I. Genetic Variation and Relatedness of Diploid Species

Isozymes were examined in the six aquatic (including amphibious) diploid species of Isoetes of eastern North America in order to quantify their levels and patterns of genetic variation, to determine their genetic distinctness, and to evaluate the utility of allozymes in addressing ancestry in the I....

Full description

Saved in:
Bibliographic Details
Published in:Systematic botany 2000-04, Vol.25 (2), p.235-259
Main Authors: Caplen, Cynthia A, Werth, Charles R
Format: Article
Language:English
Subjects:
Alleles
Diploidy
Enzymes
Gene frequency
Genetic loci
Genetic variation
Phenotypes
Plants
Population genetics
Population mean
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Isozymes were examined in the six aquatic (including amphibious) diploid species of Isoetes of eastern North America in order to quantify their levels and patterns of genetic variation, to determine their genetic distinctness, and to evaluate the utility of allozymes in addressing ancestry in the I. riparia complex. Twenty-six populations representing diploid species, I. echinospora, I. engelmannii, I. flaccida, I. mattaponi, I. prototypus, and I. valida were compared for eleven enzymes coded by 16 interpretable loci. Levels of genetic variation in populations tended to be low ranging from none (means: P = 0.0, A = 1.0, H = 0.0) in I. echinospora to moderate (means: P = 22.9, A = 1.4, H = 0.093) in I. flaccida. Genetic variation in polymorphic species tended to be distributed more among than within populations, as indicated by high Fst values (Fst > 0.607 in all polymorphic species except I.mattaponi, for which Fst = 0.272). The genetic identities of conspecific populations were high, with mean values ranging from I = 0.779/S = 0.733 in I. flaccida to I = 1.000/S = 1.000 in I. echinospora. Interspecific genetic identities were lower, with means ranging from I = 0.438/S = 0.429 between I. mattaponi and I. prototypus to I = 0.736 between I. valida and I. flaccida, and S = 0.699 between I. valida and I. prototypus. Thus the six diploids were found to be genetically distinct, corroborating their recognition based on morphology. Evidence from this study indicates that isozymes may be informative in diagnosing ancestry of allopolyploids in the Isoetes riparia complex. Communicating Editor: Anita Cholewa
ISSN:0363-6445
1548-2324
DOI:10.2307/2666641