A.C. Papageorgiou (1), I. Tsiripidis (2), S. Hatziskakis (1)

(1)Democritus University of ThraceForest Genetics Laboratory

Orestiada, Greece(2)Aristotle University of Thessaloniki

Biology Faculty, Laboratory of Plant Systematics and Plant Geography

Genetic diversity of beech in Greece

Outline

• Presentation of diversity studies about beech in Greece– cpDNA SSR markers– Leaf morphology

• Detailed diversity patterns in two areas– Southern Rodopi– Paggeo

Beech distribution in Greece

Moulopoulos, 1965

Tsiripidis, 2001

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)

Pollen data

Huntley & Birks 1983

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

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

SSR cpDNA haplotypes

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

Hatziskakis et al. 2009

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

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

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

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

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

Gene diversity in Rodopi

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

Paggeo mt.

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

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

Thank you for your attention