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Genetic characterization of Zostera noltii in the Berre Lagoon

Genetic characterization of Zostera noltii in the Berre Lagoon Caractérisation génétique des Zostera noltii de l'étang de Berre Gabriele Procaccini 1 , Ilia Serra 2 , Guillaume Bernard 3. 1 Stazione Zoologica Anton Dohrn, Napoli, Italy

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Genetic characterization of Zostera noltii in the Berre Lagoon

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  1. 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, Italy 2 Dipartimento di Ecologia, Università della Calabria, (CS) Italy 3Groupement d’Intérêt Public pour la Réhabilitation de l’étang de Berre - Berre l’étang, France

  2. Seagrasses Subclass Alismatidae (Class Liliopsida) • 4 lineages of ‘marine’ angiosperms • More independent origins of hydrophyly Ecological services Exporting organic material Protecting the coastline raising the sediment level Hosting a diversified animal and plant community (nursery role and importance for fishery)

  3. Seagrasses reproduce both sexually and asexually Sexual reproduction Vegetative reproduction

  4. Above sediment Sediment level Seagrasses vegetative spread The identification of the individual can become very difficult, do to the mode of vegetative spreading The number of genetically different individuals (genotypes) in a populations depends from the relative importance of sexual and vegetative reproduction.

  5. Seagrass Clonal Forms

  6. Environmental conditions Environmental change ? ? ? …be plastic …move …disappear Low clonal diversity High clonal diversity Population connectivity Importance of genetic diversity Understanding the genetic diversity of populations and their connectivity can shed light on the effects of environmental pressures on species distribution and evolution

  7. Z. noltii Zostera noltii Distribution and geographic structure

  8. Aims: understanding genetic diversity and isolation of Z. noltii meadows within l’étang de Berre Sampling sites Two sites within l’étang de Berre: Delta de l’Arc (Arc) and Pointe de Berre (Ber) One site in the Gulf of Carteau One site within the Brusc lagoon Genetic structure has been evaluated in relation to three Tyrrenhian sites: Livorno, Civitavecchia and Ischia Island

  9. Polimorphic Codominant Heterozygous allele 1 GAGAGAGAGAGAGAGAGAG Individual/specific genotyping minus GA allele 2 GAGAGAGAGAGAGAGAG Species-specific Microsatellites Molecular markers: nuclear DNA microsatellite Homozygous

  10. Genetic diversity

  11. H. exp. H. n.b. H. obs. P(0.95) P(0.99) Car 0.4722 0.4783 0.4834 0.7778 0.7778 Ber 0.5156 0.5237 0.4790 0.8889 0.8889 Arc 0.4425 0.4519 0.5507 0.8889 0.8889 Bru 0.4195 0.4252 0.4614 0.8889 0.8889 Heterozygosity and inbreeding High values in all four populations. No significant differences between observed and expected heterozygosity Low inbreeding High population differentiation

  12. Genetic diversity Advantage of heterozygotes?

  13. Pairwise Population Fst Car Ber Arc Bru 0,000 Car 0,112 0,000 Ber 0,140 0,063 0,000 Arc 0,196 0,172 0,159 0,000 Bru Lowest gene flow values Gene flow

  14. Principle Coordinates (1 vs 2) Car Ber Axis 2 Arc Bru Axis 1 Genetic structure Berre populations

  15. Genetic structure AFC Berre Lagoon Brusc Carteau

  16. 100% 80% 60% 40% 20% 0% Car Ber Arc Bru Assignment test Only the two populations from the Berre lagoon exchange genotyes

  17. Principal Coordinates Car Ber Arc Coord. 2 Bru IS Liv Civ Liv Civ Is Coord. 1 Latitudinal cline Clustering reflects geographic positions French populations Liv Civ Italian populations

  18. Environmental conditions • 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. Low clonal diversity High clonal diversity 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.

  19. Aknowlegements & collaborations Thank you for your attention The work has been made possible thank to a collaboration between the Stazione Zoologica Anton Dohrn and Gipreb Hans von Marées, 1873 – Fresco room, Stazione Zoologica Anton Dohrn Thanks to the SZN Molecular Biology Service for the microsatellite analysis • Funding agencies • Stazione Zoologica Anton Dohrn • Gipreb

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