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Phylogenetic Trees  Importance of phylogenetic trees  What is the phylogenetic analysis  Example of cladistics  Assumptions in cladistics  Frequently.

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Presentation on theme: "Phylogenetic Trees  Importance of phylogenetic trees  What is the phylogenetic analysis  Example of cladistics  Assumptions in cladistics  Frequently."— Presentation transcript:

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2 Phylogenetic Trees  Importance of phylogenetic trees  What is the phylogenetic analysis  Example of cladistics  Assumptions in cladistics  Frequently used terms  Fundamentals of Phylogenetc models  Phylogenetic software

3 Importance of Phylogenetic Tree Classification is important to understand Evolutionary history of an Organism Study of Biological Diversity Organization Progressive Multiple Sequence Alignment

4 What is Phylogenetic Analysis Study of evolutionary relationship Inferring or estimating relationship Usually presented as branching, tree Gene Tree: Inherited relatioships It is also called cladistics clade means branch in Greek Member of group/clade share a common rel.

5 Example of Cladistics

6 Assumptions in Cladistics Any group of oragnisms is related by descent from a common ancestor Members of a group or clade share common evolutionary history A group sharing a unique feature, different from other groups There is bifurrcating pattern of cladogenesis Change in charterstics occurs in lineages over time

7 Frequently Used Terms Clade: A monophyletic taxon. Clades are group of organisms Taxon: Named group or organisms but not necessarily a clade Branch Length: In some case it repersent divergence Node: A bifurcating branch point

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9 Fundamentals of Phylogenetic Models Sequence alignment (AMPS,Clustal-W) Substitution model (weight model) –Rates between Bases –Site Substitution(overall compositional change) Tree building Tree Evaluation

10 Tree Building Distance Based Methods –UPGMA: Unweighted Pair Group Method It is a Clustring algorithm, it cluster tree branches based on greatest similarity among pairs and averages of joined pairs –NJ: Neighbor Joining First, it join nearest pair in start and then continue till one remain Character-Based –Maximum Parismony (MP) –Maximum Likelihood (ML)

11 Tree Evaluation Randomize Tree Randomize Character Data Bootstrap Likelihood Test

12 PHYLIP PAUP PUZZLE TreeDraw MACCLAD Web Based –webphylip, PhyloBlast


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