Molecular evidence for repeated hybridization events involved in the origin of the genus × Crepidiastrixeris (Asteraceae) using RAPDs and ITS data |
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Authors: | YUKIKO SAITO MICHAEL MÖLLER GORO KOKUBUGATA TERUO KATSUYAMA WATARU MARUBASHI † TSUKASA IWASHINA |
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Institution: | School of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan; Tsukuba Botanical Garden, National Science Museum, Tokyo, Tsukuba, Ibaraki 305-0005, Japan; Royal Botanic Garden Edinburgh, 20 A Inverleith Row, Edinburgh EH3 5LR, Scotland, UK; Kanagawa Prefectural Museum of Natural History, 499 Iryuda, Odawara, Kanagawa 250–0031, Japan |
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Abstract: | We investigated the hybrid origin of × Crepidiastrixeris denticulato-platyphylla using RAPDs and ITS sequence data. The putative parents Paraixeris denticulata and Crepidiastrum platyphyllum represent separate species, irrespective of geographical origin. The occurrence of species specific RAPD markers from P. denticulata and C. platyphyllum in × C. denticulato-platyphylla established unambiguously a hybrid origin between the two taxa. This was in line with the occurrence of a combination of morphological characters such as plant habit and floret numbers. The parent taxa differed from each other by 7 nucleotide substitutions and 2 indel events in the ITS region. The hybrids showed sequence additivity and most likely represent F1 plants, with the exception of two plants which were of possible F2 origin, possessing either the ITS sequences of one parent only, or one predominant ITS type. The hybrids occurred in two out of three localities where the parents occurred sympatrically. This fact, together with the short life-span of the plants, suggests that × C. denticulato-platyphylla exists as a result of repeated, frequent hybridization between the parent species. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 333–343. |
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Keywords: | C platyphyllum intergeneric hybrid Paraixeris denticulata PCO |
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