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Phylogenetic analysis To infer and study evolutionary history of homologous gene families Manuel Ruiz (CIRAD, Data Integration team) Alexis Dereeper (IRD)

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Presentation on theme: "Phylogenetic analysis To infer and study evolutionary history of homologous gene families Manuel Ruiz (CIRAD, Data Integration team) Alexis Dereeper (IRD)"— Presentation transcript:

1 Phylogenetic analysis To infer and study evolutionary history of homologous gene families Manuel Ruiz (CIRAD, Data Integration team) Alexis Dereeper (IRD) Nathalie Chantret (INRA) Jean-François Dufayard (CIRAD, Data Integration team)

2 Species evolutionary history Species phylogeny, and molecular phylogeny Species phylogeny

3 Species evolutionary history Species phylogeny Species phylogeny, and molecular phylogeny Molecular evolutionary history Molecular phylogeny

4 Species evolutionary history Species phylogeny Species phylogeny, and molecular phylogeny Molecular evolutionary history Molecular phylogeny Modeling (trees) Modeling (sequences, trees)

5 Species phylogeny, and molecular phylogeny Wheat Rice Tomato Sequence 1 (wheat) Sequence 2 (rice) Sequence 3 (tomato) To infer evolutionary gene history... Permits to infer evolutionary species history ? What signal is supported by sequences ? Are speciations the only important events ?

6 Species phylogeny, and molecular phylogeny Wheat Rice Tomato Duplication Sequence 1 (wheat) Sequence 2 (rice) Sequence 3 (tomato) Sequence 4 (wheat) Sequence 5 (rice) Sequence 6 (tomato)

7 Species phylogeny, and molecular phylogeny Wheat Rice Tomato Gene losses Sequence 1 (wheat) Loss (rice) Sequence 3 (tomato) Loss (wheat) Sequence 5 (rice) Loss (tomato)

8 Species phylogeny, and molecular phylogeny Wheat Rice Tomato Losses Sequence 1 (wheat) Sequence 3 (tomato) Sequence 5 (rice)

9 Species phylogeny, and molecular phylogeny Wheat Rice Tomato Tree reconciliation Sequence 1 (wheat) Loss (rice) Sequence 3 (tomato) Loss (wheat) Sequence 5 (rice) Loss (tomato) Sequence 1 (wheat) Sequence 3 (tomato) Sequence 5 (rice)

10 Definitions Sequence 1 (wheat) Sequence 2 (rice) Sequence 3 (tomato) Sequence 4 (wheat) Sequence 5 (rice) Sequence 6 (tomato) Similarity: mathematical measure of similarity between two sequences (quantitative concept). Coverage: relative or absolute length along which two sequences are comparable. Homology: two molecules are homologous if they have derived from a common ancestral molecule (qualitative concept). Orthologous genes : genes derived from a common ancestor and diverged after a speciation event, they belong to different species. Paralogous genes : genes derived from a common ancestor and diverged after a duplication event, they can belong to the same species. In silico In vivo

11 Starting data 4 sequences from the reference transcriptome of Oryza sativa 1 mapped consensus sequence, for each individual (10 crop african rice et 1 wild african rice). Os2g25612Os3g52163Os4g66669 RC1 RC2 RC3... RS7

12 Alignment and cleaning: Align similar portions between sequences, and select conserved bloc in order to support the homology hypothesis. Workflows Clustering: Retrieve homologous gene families Spot paralogies anterior to the Oryza sativa / Oryza glaberima divergence. Oryza sativa transcriptome: Sequence1_SATIVA Sequence2_SATIVA... Consensus Oryza glaberima / Oryza barthii: Sequence1_RC1 Sequence2_RS1... Phylogenetic reconstruction: Find a tree likely to explain the alignment in a given model of evolution. Analyse: Display, rooting, reconciliation Interspecifique / inter-genderIntraspecifique / intra-gender

13 Alignment and cleaning: Align similar portions between sequences, and select conserved bloc in order to support the homology hypothesis. Workflows Clustering: Retrieve homologous gene families Spot paralogies anterior to the Oryza sativa / Oryza glaberima divergence. Oryza sativa transcriptome: Sequence1_SATIVA Sequence2_SATIVA... Consensus Oryza glaberima / Oryza barthii: Sequence1_RC1 Sequence2_RS1... Phylogenetic reconstruction: Find a tree likely to explain the alignment in a given model of evolution. Analyse: Display, rooting, reconciliation Interspecifique / inter-genderIntraspecifique / intra-gender Similar sequences from distant species: Sequence1_MAIZE Sequence2_SORBI... BLAST on public databanks: Search homologous genes from several distant species Clarify the dates for duplication events

14 Homologous search in public databanks BLAST :


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