Hybrid zones in Rhododendron subsection Taliensia
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Date
27/06/2011Author
Marczewski, Tobias
Metadata
Abstract
The investigation of hybrid zones has proven to be one of the most promising
approaches to advance our understanding of species barriers, and to elucidate
evolutionary processes involved in speciation. Due to the improvement of molecular
techniques it will soon be possible to investigate the genetic composition
of non-model species in much greater detail, and also include species that defy
investigation using controlled laboratory conditions. To be able to draw further
reaching conclusions about the generality of certain evolutionary factors, it is
crucial to investigate a wide spectrum of organisms differing in traits, life histories
and relatedness. This study investigates patterns of hybridisation between two
pairs of closely related species in the genus Rhododendron. AFLP data for
346 loci, from twelve populations in total comprising 390 individuals, were
obtained. Additionally, the abundance of three alkane components in the leaf
waxes of 115 individuals was determined. For the species pair R. clementinae
and R. roxieanum low levels of recent hybridisation were found, however, the wax
composition of R. roxieanum var. cucullatum suggests historical introgression.
Two types of hybrid zones were found for R. aganniphum and R. phaeochrysum,
one mainly comprising F1 individuals, and the other frequent backcrosses to
R. aganniphum. Furthermore, evidence for genomic incompatibilities at several
loci for the two species will be presented, and hybrid identity of R. aganniphum
var.
avorufum and R. phaeochrysum var. agglutinatum is suggested.
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