Genetic characterization of Zostera noltii in the Berre Lagoon Caractérisation génétique des...
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Transcript of Genetic characterization of Zostera noltii in the Berre Lagoon Caractérisation génétique des...
Genetic characterization of Zostera noltii in the Berre Lagoon
Caractérisation génétique des Zostera noltii de l'étang de Berre
Gabriele Procaccini1, Ilia Serra2, Guillaume Bernard3
1 Stazione Zoologica Anton Dohrn, Napoli, Italy2 Dipartimento di Ecologia, Università della Calabria, (CS) Italy3 Groupement d’Intérêt Public pour la Réhabilitation de l’étang de Berre - Berre l’étang, France
Subclass Alismatidae(Class Liliopsida)
• 4 lineages of ‘marine’ angiosperms
• More independent origins of hydrophyly
Seagrasses
Ecological services
Exporting organic materialProtecting the coastline raising the sediment levelHosting a diversified animal and plant community(nursery role and importance for fishery)
Vegetative reproduction Sexual reproduction
Seagrasses reproduce both sexually and asexually
The number of genetically different individuals (genotypes) in a populations depends from the relative
importance of sexual and vegetative reproduction.
Above sediment
Sediment level
Seagrasses vegetative spread
The identification of the individual can become very difficult, do to the mode of vegetative spreading
Seagrass Clonal Forms
Environmental conditions
High clonal diversityLow clonal diversity
Population connectivity
Understanding the genetic diversity of populations and their connectivity can shed light on the effects of environmental pressures on species
distribution and evolution
…disappear
?
…move
?…be plastic
?
Environmental change
Importance of genetic diversity
Z. noltii
Zostera noltii
Distribution and geographic structure
Sampling sitesTwo sites within l’étang de Berre: Delta de l’Arc (Arc) and Pointe de Berre (Ber) One site in the Gulf of CarteauOne site within the Brusc lagoonGenetic structure has been evaluated in relation to three Tyrrenhian sites:Livorno, Civitavecchia and Ischia Island
Aims: understanding genetic diversity and isolation of Z. noltii meadows within l’étang de Berre
Molecular markers: nuclear DNA microsatellite
Microsatellites
GAGAGAGAGAGAGAGAGAG
GAGAGAGAGAGAGAGAG
minus GA
allele 1
allele 2
Polimorphic
Codominant
Individual/specific genotyping
Species-specific
HeterozygousHomozygous
N G G/N A/locusPrivate alleles
Car 40 39 0.975 4.111 11
Ber 40 32 0.8 4.000 7
Arc 40 23 0.575 2.889 2
Bru 40 37 0.925 2.778 6
Genetic diversity
0.88890.88890.46140.42520.4195Bru
0.88890.88890.55070.45190.4425Arc
0.88890.88890.47900.52370.5156Ber
0.77780.77780.48340.47830.4722Car
P(0.99)P(0.95)H. obs.H. n.b.H. exp.
Heterozygosity and inbreeding
High values in all four populations. No significant differences between observed and expected heterozygosity
Weir & Cockerham FIS= -0.04266 FIT= 0.22787 FST= 0.25946
Low inbreeding High population differentiation
Genetic diversity
N G G/N A/locus Ho He
Car 40 39 0.975 4.111 0.4834 0.4722
Ber 40 32 0.8 4.000 0.4790 0.5156
Arc 40 23 0.575 2.889 0.5507 0.4425
Bru 40 37 0.925 2.778 0.4614 0.4195
N G G/N A/locus Ho He
Liv 25 20 0.80 5.25 0.4878 0.6027
Civ 31 25 0.80 4.65 0.5150 0.5697
Advantage of heterozygotes?
Bru0,0000,1590,1720,196
Arc0,0000,0630,140
Ber0,0000,112
Car0,000
BruArcBerCar
Pairwise Population Fst
Lowest gene flow values
Gene flow
Principal Coordinates
Bru
Arc
Ber
Car
Coord. 1C
oo
rd.
2
Principle Coordinates (1 vs 2)
Axis 1
Axi
s 2
Car
Ber
Arc
Bru
Berre populations
Genetic structure
Berre Lagoon
Carteau
Brusc
AFC
Genetic structure
0%
20%
40%
60%
80%
100%
Car Ber Arc Bru
Assignment test
Only the two populations from the Berre lagoon exchange genotyes
Principal Coordinates
Coord. 1
Co
ord
. 2
Car
Ber
Arc
Bru
Liv
Civ
French populations
Italian populations
LivCiv
Principal Coordinates
Coord. 1
Co
ord
. 2
CarBerArcBruISLivCiv
Latitudinal cline
LivCivIs
Clustering reflects geographic positions
Conclusions
• Populations within the Berre lagoon, particularly Arc, have lower number of alleles and lower genotypic diversity in respect to the others. This is a potential problem for the persistence of the meadows.
• Heterozygosis is high in all populations. There are not signs of inbreeding suggesting that sexual reproduction is active within the lagoon.
Environmental conditions
High clonal diversityLow clonal diversity
• Populations within the Berre lagoon are isolated from the ones in the open sea, but closer to the Carteau population.
• A cline seems to be present between Brusc and the other three French populations, reflecting patterns of gene flow and suggesting preferencial sites for collection of genotypes in transplanting strategies
• Clustering among all populations reflects geographic positions.
Funding agencies
• Stazione Zoologica Anton Dohrn• Gipreb
Thanks to the SZN Molecular Biology Service for
the microsatellite analysis
Hans von Marées, 1873 – Fresco room, Stazione Zoologica Anton Dohrn
The work has been made possible thank to a collaboration between the Stazione Zoologica Anton Dohrn and
Gipreb
Thank you for your attention
Aknowlegements & collaborations