Systematics/Phytogeography / Taxonomie/ Section
Crawford, Daniel J. , Archibald, Jenny K. , Stoermer, Danielle , Mort, Mark E. , Santos-Guerra, Arnoldo .
Breeding Relationships Among Species and Populations of Tolpis (Asteraceae) Endemic to the Canary Islands.
Tolpis (Asteraceae) is a small genus of fewer than 20 species; the clade containing all Canary Island endemics comprises over half the taxa. There are several morphologically distinct species in the Canaries and a variable complex of morphologically-intergrading species (T. laciniata-T. lagopoda complex). Despite divergence in several ecological-life history features during radiation in the Canaries, extensive sequencing of nuclear and plastid regions has not resolved relationships in Tolpis; hypervariable ISSR markers were used to produce a tree. Pollen fertility of synthetic F1 hybrids was used to examine breeding relationships among species and within the T. laciniata-T. lagopoda complex. One of two significant findings is that certain hybrids show very low fertilities, being almost completely sterile. Another finding is that hybrid fertility does not match well with expectations based on morphological and genetic distinctiveness (the latter assessed via allozymes and ISSR markers). That is, hybrids between easily-distinguishable species are in some cases very fertile whereas hybrids between some populations within the variable complex are highly sterile. Tolpis does not fit the general model of uniformly high fertility among elements of island lineages, nor do breeding relationships reflect the current taxonomic treatment or view of relationships in Canarian Tolpis. The factors responsible for hybrid sterility are not known and are being investigated; prior work by Jarvis implicates chromosomal rearrangements as one contributing factor.
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1 - University of Kansas, Department of Ecology & Evolutionary Biology, Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
2 - University of Kansas, Department of Ecology & Evolutionary Biology, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
3 - St. Olaf College, Department of Biology, Northfield, Minnesota, 55057, USA
4 - Jardín de Aclimatación de La Orotava, Puerto de la Cruz, Canary Islands, Tenerife, Spain
Presentation Type: Oral Paper:Papers for Sections
Location: Room 5/Woodward
Date: Tuesday, July 29th, 2008
Time: 3:00 PM