Diversification o f Mediterranean Cystoseira (Fucales, Phaeophyceae)
using a RAD-Seq approach
Zervas D im itrios, Kyung Min Lee, Sofie D’Hondt and O livier de Clerck
Phycology Research Group, Ghent University, Krijgslaan 2 81 -S8, 9000 Ghent, Belgium
E-mail: dim itriszer@ vahoo.qr
The brown algal genus Cystoseira represents a very im p o rta n t com ponent o f shallow w ater coastal
environm ents in the Mediterranean Sea. The plants typ ically fo rm dense vegetations, creating a
habitat fo r a m ultitu de o f vertebrate and invertebrate species. A b o u t 29 d iffe re n t taxa (species and
intraspecific taxa) have been recognized. Resolving th e ir e volutionary relationship however proves
very d iffic u lt, due to the recency o f th e ir origin and m ost probably ongoing hybridisation between
closely related taxa. In th is study we aim to investigate the e volutionary h istory o f the Cystoseira
(clade-5 sensu Draimsa et al. 2010) and disentangle the roles o f geography versus and ecology in
the d iversification process. Seven species have been selected: C. am entacea var. stricta,
C. brachycarpa, C. c rin ita , C. funki, C. m editerranea, C. ta m a ris c ifo lia and C. zostertoides. Most o f
the individuals sampled were located across the M editerranean Sea, w ith few o f them collected from
the A tla n tic coasts o f Spain and France.
Restriction site Associated DNA (RAD) tags, were used, as a cost-effective polym orphism
ide ntifica tion m ethod, to be up to par w ith the evolving Next Generation Sequencing Techniques
(Davey e t al., 2011). RAD tags are genome wide, short DNA sequences, associated w ith a specific
restriction enzyme. We used S b f\to generate thousands o f markers fro m which gene and species
w ill be constructed under a m ultispecies coalescent fram ew ork.
Our study presents the firs t RAD-Seq approach fo r algal species. Results are expected to provide
new insights on C ystoseira’s phylogeny and d iversification in the M editteranean basin fo llo w in g the
end o f the Messinian salinity crisis (5 mya).
References
DaveyJ.W., P.A. Hohenlohe, P.D. Etter, J.Q. B ooneJ.M . Catchen and M.L. Blaxter. 2011 Genome-wide
genetic m arker discovery and genotyping using next-generation sequencing. Nature Reviews
Genetics 12:499-510.
Draisma S.G.A., e. Ballesteros, F. Rousseau and T. T hibaut. 2010. DNA sequence data dem onstrate
the polyphyly o f the genus cystoseira and o the r Sargassaceae genera (Phaeophyceae). Journal
o f Phycology 46:1329-1345.
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