10.5061/DRYAD.43HD6
Montecinos, Alejandro E.
Sorbonne University
University Austral de Chile
Guillemin, Marie L.
Agrocampus Ouest
Couceiro, Lucia
Sorbonne University
Peters, Akira F.
Evolutionary Biology and Ecology of Algae
Stoeckel, Solenn
Agrocampus Ouest
Valero, Myriam
Sorbonne University
Guillemin, Marie-Laure
Sorbonne University
University Austral de Chile
Data from: Hybridization between two cryptic filamentous brown seaweeds
along the shore: analysing pre- and post-zygotic barriers in populations
of individuals with varying ploidy levels
Dryad
dataset
2017
post-zygotic reproductive barrier
Meiosis
haploid-diploid life cycle
reproductive barriers
Ectocarpus
haploid diploid life cycle
gametophyte and sporophyte
shore gradient
gametophyte
sporophyte
2017-02-23T16:22:27Z
2017-02-23T16:22:27Z
en
https://doi.org/10.1111/mec.14098
146454 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
We aimed to study the importance of hybridization between two cryptic
species of the genus Ectocarpus, a group of filamentous algae with
haploid-diploid life cycles that include the principal genetic model
organism for the brown algae. In haploid-diploid species, the genetic
structure of the two phases of the life cycle can be analysed separately
in natural populations. Such life cycles provide a unique opportunity to
estimate the frequency of hybrid genotypes in diploid sporophytes and
meiotic recombinant genotypes in haploid gametophytes allowing the effects
of reproductive barriers preventing fertilization or preventing meiosis to
be untangle. The level of hybridization between E. siliculosus and E.
crouaniorum was quantified along the European coast. Clonal cultures (568
diploid, 336 haploid) isolated from field samples were genotyped using
cytoplasmic and nuclear markers to estimate the frequency of hybrid
genotypes in diploids and recombinant haploids. We identified admixed
individuals using microsatellite loci, classical assignment methods and a
newly developed Bayesian method (XPloidAssignment), which allows the
analysis of populations that exhibit variations in ploidy level. Over all
populations, the level of hybridization was estimated at 8.7%. Hybrids
were exclusively observed in sympatric populations. More than 98% of
hybrids were diploids (40% of which showed signs of aneuploidy) with a
high frequency of rare alleles. The near absence of haploid recombinant
hybrids demonstrates that the reproductive barriers are mostly
post-zygotic and suggests that abnormal chromosome segregation during
meiosis following hybridisation of species with different genome sizes
could be a major cause of interspecific incompatibility in this system.
Genotypes sporophytesGenotypes of sporophytes individuals identified
(based on diagnostic microsatellite, ITS1 and species-specific cytoplasmic
marker) as E. siliculosus (Esil, n = 338) and E. crouaniorum (Ecro, n =
151). This identification was used previous to the admixture analyses. The
number of samples in each population, name of the strain, ITS1 length (850
= Esil, >1000 = Ecro) and positive amplification in the cytoplasmic
marker (Esil = positive amplification Esil, Ecro = positive amplification
Ecro) are shown. In diagnostic loci, the non-amplification in one of the
parental species corresponds to a phylogenetic signal but should be
distinguished from a null allele. To solve this problem, these missing
data points were replaced by an artificial allele of an arbitrary size of
(800bp). In contrast, missing data or null alleles were noted as
0.Genotype Sporophyte.xlsxGenotype gametophyteGenotypes of gametophytes
individuals identified (based on diagnostic microsatellite, ITS1 and
species-specific cytoplasmic marker) as E. siliculosus (Esil, n = 158) and
E. crouaniorum (Ecro, n = 176). This identification was used previous to
the admixture analyses. The number of samples in each population, name of
the strain, ITS1 length (850 = Esil, >1000 = Ecro) and positive
amplification in the cytoplasmic marker (Esil = positive amplification
Esil, Ecro = positive amplification Ecro) are shown. In diagnostic loci,
the non-amplification in one of the parental species corresponds to a
phylogenetic signal but should be distinguished from a null allele. To
solve this problem, these missing data points were replaced by an
artificial allele of an arbitrary size of (800bp). In contrast, missing
data or null alleles were noted as 0.Genotype Gametophyte.xlsx