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ADAPTIVE RADIATION AND GENETIC DIFFERENTIATION IN THE HAWAIIAN SILVERSWORD ALLIANCE (COMPOSITAE: MADIINAE)
Author(s) -
Witter Martha S.,
Carr Gerald D.
Publication year - 1988
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1988.tb04187.x
Subject(s) - biology , adaptive radiation , evolutionary biology , range (aeronautics) , genetic variation , interspecific competition , genetic distance , taxon , genetic variability , ecology , genetics , phylogenetics , gene , materials science , genotype , composite material
The Hawaiian silversword alliance consists of the three genera Dubautia, Argyroxiphium , and Wilkesia , and is a classic example of adaptive radiation in an insular setting. Genetic variation and interspecific genetic differentiation based on ten enzyme loci are described for Dubautia and Wilkesia . Genetic identities among species span the range of values expected from interpopulation comparisons within a single species ( I = 0.90–1.00) to those typical of interspecific comparisons ( I → = 0.67 ) . Genetic‐identity values correspond to biogeographic distribution and morphological distinctiveness, supporting a correlation of increasing genetic distance associated with the time of separation among lineages. It may be inferred that the high genetic identities observed within the Hawaiian Madiinae and other island plant groups are due to limited time spans available for taxa to accumulate new genetic variation through mutation. It appears that species may remain genetically similar ( I > 0.90) even after time spans on the order of magnitude of 1,000,000 years.