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The allopolyploid Arabidopsis kamchatica originated from multiple individuals of Arabidopsis lyrata and Arabidopsis halleri

Type of publication Not peer-reviewed
Publikationsform Original article (non peer-reviewed)
Publication date 2009
Author SHIMIZU-INATSUGI RIE, LIHOVÁ JUDITA, IWANAGA HIROKO, KUDOH HIROSHI, MARHOLD KAROL, SAVOLAINEN OUTI, WATANABE KUNIAKI, YAKUBOV VALENTIN V., SHIMIZU KENTARO K.,
Project Adaptation and speciation: evolutionary genomic analysis using arabidopsis relatives
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Original article (non peer-reviewed)

Journal Molecular Ecology
Volume (Issue) 18(19)
Page(s) 4024 - 4048
Title of proceedings Molecular Ecology
DOI 10.1111/mec.2009.18.issue-19

Abstract

Polyploidization, or genome duplication, has played a critical role in the diversification of animals, fungi and plants. Little is known about the population structure and multiple origins of polyploid species because of the difficulty in identifying multiple homeologous nuclear genes. The allotetraploid species Arabidopsis kamchatica is closely related to the model species Arabidopsis thaliana and is distributed in a broader climatic niche than its parental species. Here, we performed direct sequencing of homeologous pairs of the low-copy nuclear genes WER and CHS by designing homeolog-specific primers, and obtained also chloroplast and ribosomal internal transcribed spacer sequences. Phylogenetic analysis showed that 50 individuals covering the distribution range including North America are allopolyploids derived from Arabidopsis lyrata and Arabidopsis halleri. Three major clusters within A. kamchatica were detected using Bayesian clustering. One cluster has widespread distribution. The other two are restricted to the southern part of the distribution range including Japan, where the parent A. lyrata is not currently distributed. This suggests that the mountains in Central Honshu and surrounding areas in Japan served as refugia during glacial–interglacial cycles and retained this diversity. We also found that multiple haplotypes of nuclear and chloroplast sequences of A. kamchatica are identical to those of their parental species. This indicates that multiple diploid individuals contributed to the origin of A. kamchatica. The haplotypes of low-copy nuclear genes in Japan suggest independent polyploidization events rather than introgression. Our findings suggest that self-compatibility and gene silencing occurred independently in different origins.
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