Phylogéographie et voies de recolonisation

Transcription

1 Phylogéographie et voies de recolonisation Atelier Banyuls Juin 2006 R. Petit

2 Project UE Fairoak Chloroplast DNA diversity of oaks in Europe

3 D après Petit et al. 2002

4 D après Petit et al. 2002

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7 7 Etude phylogéographique d une invasion Cas du Quercus ilex et virus de la grippe Valoriser l information sur l anagenèse et pas seulement la cladogenèse (nestedness)

8 25 haplotypes / 5 restr. enz.. / 698 trees / 174 populations 6

9 5 22 mutations 20 mutations 16 mutations 14 mutations 9 mutations 2 mutations

10 Evolutionary rates are not constant 26 but depend on many factors: Mutation rate

11 Rate variation due to differences in 25 mutation rates Mutation rates (DNA replication or repair)

12 Evolutionary rates are not constant 24 but depend on many factors: Mutation rate Generation time

13 Rate variation due to differences in 23 generation time Mechanism remains unclear

14 Evolutionary rates are not constant 22 but depend on many factors: Mutation rate Generation time Diversification rate

15 Rate variation due to differences in 21 diversification rates Type of trap Pinguicula Utricularia The rationale is that random drift acting within the bottleneck period for the founder population involved in the speciation event might increase the rate of substitution throughout the affected genomes

16 Evolutionary rates are not constant 20 but depend on many factors: Mutation rate Generation time Diversification rate Colonization? Affects the tempo of evolution? If so: use branch length information to study colonization history of lineages, a major goal of biogeography

17 Accumulation de mutations durant 19 une invasion? Populations ou espèces Petit et al. Taxon, 2005

18 Accumulation of differences during 18 invasion? Mean branch length of haplotypes for populations (species)

19 Increased number of repeats at 17 microsatellites during invasion? Average number of repeats per population (species) -AGAGAGAGAGAG- -AGAGAGAGAG- -AGAGAGAG- -AGAGAG- -AGAG- cf. the upward mutation bias at many microsatellites

20 Alternative mode of data 16 presentation Number of repeats > mean Number of repeats < mean -AGAGAGAGAGAG- -AGAGAGAGAG- -AGAGAGAG- -AGAGAG- -AGAG-

21 SSR allele size as a measure of the accumulation of derived mutations 15 Average SSR allele size Ancestral population Derived populations SSR 99 loci

22 Accumulation of differences 14 through time Influenza virus Influenza evolution Continuous replacement of circulating strains with new variants results in a particular phylogeny with a slender trunk that develops across the years (Ferguson et al. Nature 2003)

23 No change without movement Pierre Bourdieu Bourdieu, P., (1999), No Change without Movement, Le Monde Diplomatique, 5 June, pp.1-3.

24 7 haplotypes / 6 ssr loci / 248 trees / 26 populations cp microsatellite variation in hazelnut (Corylus avellana) 13

25 Mean cp microsatellites length in hazelnut (Corylus avellana) 12 Long cpssrs Short cpssrs

26 Chloroplast microsatellite variation in the common beech (Fagus sylvatica) Long cpssrs Short cpssrs 26 haplotypes / 6 ssr loci / 2815 trees / 468 populations Magri et al. in press New Phytol

27 15 isozyme loci / trees / 389 populations 10 Trends in allelic richness in the beech Allelic Richness 500 km

28 the presence of some taxa in the Middle East and in Europe (F. excelsior, F. oxyphylla, F. pallisae, and F. syriaca) is more likely due to progressive dispersal from eastern Asia to Europe than to a quite recent intercontinental migration from North America to Europe. 4

29 12 haplotypes / 6 ssr loci / 1280 trees / 201 populations Mean cp microsatellites length in the common ash (Fraxinus excelsior) Long cpssrs Short cpssrs 3

30 Longueur des microsatellites cp pour les arbres européens 11 Long cpssrs Short cpssrs

31 Phylogeographie du hêtre en Europe billion mature individuals 0.5 billion (im)mature individuals

32 Chloroplast microsatellite variation in the common beech (Fagus sylvatica) Long cpssrs Short cpssrs 26 haplotypes / 6 ssr loci / 2815 trees / 468 populations Magri et al. in press New Phytol

33 15 isozyme loci / trees / 389 populations Trends in allelic richness in the beech Allelic Richness km

34 Premières conclusions (fausses!) Refuges en Italie et surtout dans les Balkans Invasion vers l ouest à l Holocène, suggérée par les données ADNcp et les patrons de richesse allélique et les données palynologiques Mais

35 Données macrofossiles Magri et al. New Phytol 2006

36 Genetic structure based on isozymes SAMOVA: 387 pops, 12 loci (7 groups) Magri et al. New Phytol 2006

37 Numerous LGM refugia, including at rather high latitudes, including in the west Mediterranean refugia not the source of northward migration A single strong refugium near Slovenia has been a major source of colonization Magri et al. New Phytol in press

38 Current cpdna genetic structure + Magri et al. New Phytol in press

39 Magri et al. New Phytol in press

40 Magri et al. New Phytol in press

41 Magri et al. New Phytol in press

42 Magri et al. New Phytol in press

43 Magri et al. New Phytol in press

44 Magri et al. New Phytol in press

45 Magri et al. New Phytol in press

46 Magri et al. New Phytol in press

47 Magri et al. New Phytol in press

48 Magri et al. New Phytol 2006

49 Several non-mediterranean refugia characterized by the same cpdna variant Despite isolation >one glacial/interglacial (more likely >400 kyrs), no mutation accumulated (and no new isozyme alleles) The assumed westward migration took place but much earlier, not during the Holocene Current Magri et al. New Phytol in press

50 2 Genetic architecture of a species range LEADING EDGE ~10 4 yrs ago Refugial (=source) populations REAR EDGE Relict populations >10 6 yrs ago

51 Genetic structure based on isozymes SAMOVA: 387 pops, 12 loci (7 groupes) Magri et al. New Phytol 2006

52 Genetic structure based on isozymes SAMOVA: 387 pops, 12 loci (4 groupes) Magri et al. New Phytol 2006