Genetic diversity of beech in Greece


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Genetic diversity of beech in Greece

  1. 1. Genetic diversity of beech in Greece A.C. Papageorgiou (1) , I. Tsiripidis (2) , S. Hatziskakis (1) Democritus University of Thrace (1) Forest Genetics Laboratory Orestiada, Greece (2) Aristotle University of Thessaloniki Biology Faculty, Laboratory of Plant Systematics and Plant Geography
  2. 2. Outline• Presentation of diversity studies about beech in Greece – cpDNA SSR markers – Leaf morphology• Detailed diversity patterns in two areas – Southern Rodopi – Paggeo
  3. 3. Beech distribution in Greece Moulopoulos, 1965 Tsiripidis, 2001
  4. 4. Beech in Greece• Mountainous “island” populations• Broad range of ecological conditions• One species, with two interfertile subspecies – Fagus sylvatica var. sylvatica – Fagus sylvatica var. orientalis• At least two glacial refugia (pollen data)
  5. 5. Pollen dataHuntley & Birks 1983
  6. 6. Genetic diversity of beech in Europe• High nuclear DNA diversity within populations• Low cpDNA diversity and differentiation• Diversity higher in the Balkans• More cpDNA haplotypes in Italy and the Balkans
  7. 7. Latest theory about beech origin• European beech derives mainly from migration out of refugia in Istria and S. France• Italian lineages were blocked• Balkan lineages did not expand much after the last glaciation period• Beech did not migrate from the Balkans to the north – The opposite is rather assumed
  8. 8. SSR cpDNA haplotypes
  9. 9. cpDNA haplotypes in Greece• 40 populations sampled covering the whole geographical range – 38 in Greece – 2 in East Thrace (Turkey)• 5 trees / population• 3 polymorphic SSR primers• 13 haplotypes
  10. 10. Hatziskakis et al. 2009
  11. 11. Beech cpDNA patterns in Greece• High overall variation• Very high differentiation among populations – Low spatial geographic structure• Explanation – At least 3 refugial areas • Pindos, Rodopi, Paggeo – Distant and close-by lineages • North and Rodopi haplotypes migration – Introgression between two subspecies • “orientalis” influence in eastern and central Greece
  12. 12. TCS haplotype network• Mutational steps• Western and northern haplotypes group together• Eastern haplotypes have common origin with the Rodopi ones• Possible common origin during past glacial periods
  13. 13. Leaf morphology• Same 40 populations• 25 trees / population and 20 leaves / tree• Leaves scanned and stored digitally• More than 30 characters measured – Systematically important• Multivariate statistics – PCA – Clustering – Grouping defined by genetic results
  14. 14. Results• High diversity• Four PCA axes – First two PCA axes explain 80% of variation • Size and shape – Next two only 10% • Petiole and leaf perimeter• Leaf morphology follows geographical and environmental parameters• Lineages defined by cpDNA haplotypes also show some influence
  15. 15. Beech in Rodopi• Morphology changes from east to west – Indicating an introgression zone• Genetic diversity increases in the eastern part of the mountain – In cpDNA (SSR) and genomic DNA (AFLPs)• Eastern haplotypes located in eastern part of the mountain• Eastern lineage occupies lower altitudes, while a western lineage occupies higher altitudes – Adaptation (?) – Migration history – Both in gene markers and morphology
  16. 16. Gene diversity in Rodopi
  17. 17. Beech in Paggeo mt.• NE Greece• Isolated massif• Near a refugial area• Beech coverage over different altitudes (600 – 1700m)• Different beech ecotypes – Described by plant communities
  18. 18. Paggeo mt.
  19. 19. Beech diversity in Paggeo• Eastern cpDNA haplotypes cover the higher altitudes while western haplotypes the lower ones – The opposite trend than Rodopi• Leaf morphology indicated the opposite – Environmentally influenced in small scale• Complex post glacial movement in time and space resulted in this pattern – Eastern haplotypes climbed the north slope to the top – Local refugial haplotype remained in the central part of the mountain – Western haplotypes remained in low elevations
  20. 20. In conclusion• Beech in Greece has a complex diversity pattern deriving from different lineages from close-by or distant refugia• Introgression of the two subspecies is evident, especially in the north-east• Morphological traits follow both environmental and genetic grouping• Mountains contain complex structures in a small scale, indicating complex migration events
  21. 21. Thank you for your attention