Chloroplast DNA and Allozymic Variation in Diploid and Autotetraploid Heuchera grossulariifolia (Saxifgragaceae)

Document Type

Article

Journal/Book Title/Conference

American Journal of Botany

Volume

77

Publication Date

1-1-1990

First Page

232

Last Page

244

Abstract

Diploid and autotetraploid populations of Heuchera grossulariifolia occur throughout mountainous regions of the Pacific Northwest. Controlled greenhouse crosses indicated that the two cytotypes are largely reproductively isolated. Fourteen diploid and 11 tetraploid populations were analyzed electrophoretically. Individual tetraploid plants expressed up to four alleles per isozyme locus, and tetraploid populations had significantly higher levels of heterozygosity than diploids. Mean observed heterozygosity was 0.159 for tetraploid populations and 0.058 for diploid populations. The patterns of allelic distribution betwecn cytotypes suggested multiple origins of autotetraploids. This hypothesis was supported by restriction-site analysis of chloroplast-DNA (cpDNA) variation which indicated that there had been at least three independent origins of tetraploids. Electrophoretic data, in conjunction with a cpDNA-based phylogeny and geographic distribution of populations, suggest that autopolyploid populations evolved several times as migration of diploids occurred down river systems. This study further supports the contention that autopolyploidy can be a common and successful speciation process in some groups of plants.

This document is currently not available here.

Share

COinS