dc.contributor.author | Marquardt, Jeannine | |
dc.date.accessioned | 2017-09-26T13:17:29Z | |
dc.date.available | 2017-09-26T13:17:29Z | |
dc.date.issued | 2017-05-11 | |
dc.date.submitted | 2017-09-26T13:32:07.465Z | |
dc.identifier.citation | Marquardt, J. 2017. Hybridisation in bluebells (Hyacinthoides spec.) Using next-generation sequencing to reconstruct a natural hybrid zone in Spain. Queen Mary University of London | en_US |
dc.identifier.uri | http://qmro.qmul.ac.uk/xmlui/handle/123456789/25908 | |
dc.description | PhD | en_US |
dc.description.abstract | Hybridisation is a common evolutionary process that can arise in primary or secondary
contact. Gene
ow and/or reproductive isolation between hybridising taxa can be explored
in hybrid zones. Therefore, a (homoploid) hybrid zone in north-west Spain between
Hyacinthoides non-scripta and H. hispanica was studied. The centre occurs west
to east across the Galicio-Duero Mountains with H. non-scripta distributed north, and
H. hispanica south of the centre. The hybrids' genome sizes and phenotypes represented a
range of intermediate states between their parents. Crossing and seed germination experiments
revealed a low inter-speci c barrier, and the hybrids showed similarly good tness.
Genome wide markers for large genome species were designed from transcriptomes. Diagnostic
SNPs between H. non-scripta and H. hispanica were targeted and re-sequenced with
multiplexing PCR. Coalescence analyses suggested a Pleistocene origin of parapatric speciation
between H. non-scripta and H. hispanica. These results are supported by shared
inter-speci c polymorphisms, the lack of recent hybrid generations and of parental individuals
in sympatry. Di erential introgression patterns between the organellar and nuclear
genomes revealed that formerly H. hispanica ranged further north but was swamped by
H. non-scripta alleles. Asymmetric hybridisation was reasoned by absence of backcrosses
between northern hybrids to H. non-scripta, but presence between southern hybrids and
H. hispanica. Combining these results, a southwards movement of the hybrid zone centre
caused by climate change (and adaptive introgression), or inter-speci c di erences in
owering
time was suggested. Cline patterns revealed cyto-nuclear incompatibilities, which
could evolve through divergent adaptation of the organelle to climate and a delayed selection
on nuclear inter-acting loci. Both species are in secondary contact in the UK due to
recent introduction(s) of H. hispanica and garden variants, which is considered to cause
genetic pollution of native H. non-scripta. Therefore, a conservation study is in progress,
in which this diagnostic marker system for bluebells is applied. | en_US |
dc.description.sponsorship | QMUL Doctoral College and the European Marie Curie Initial Training Network `INTERCROSSING' [PITN-GA-2011-289974]. | en_US |
dc.language.iso | en | en_US |
dc.publisher | Queen Mary University of London | en_US |
dc.rights | The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author | |
dc.subject | Bluebells | en_US |
dc.subject | Hybridisation | en_US |
dc.subject | Plant biology | en_US |
dc.title | Hybridisation in bluebells (Hyacinthoides spec.) Using next-generation sequencing to reconstruct a natural hybrid zone in Spain | en_US |
dc.type | Thesis | en_US |