in this ppt i has explained about phylogenetic tree

1. PATNA SCIENCE COLLEGE
DEPARTMENT OF ENVIRONMENTAL SCIENCE
SUBMITTED
BY
SAMIKSHA
ROLL NO -16
CC12
ORGANISM AND
EVOLUTIONARY
BIOLOGY

2. PHYLOGENETIC TREE
1. INTRODCTION
2. PHYLOGENY APPLICATION
3. TYPES OF PHYLOGENETIC TREE
4. CONSTRUCTING PHYLOGENETIC TREE
5. DISTANCE BASED METHODS
6. REFERENCES

3. INTRODUCTION
 A phylogenetic tree or evolutionary tree is a branching
diagram or ‘tree showing the evolutionary relationships
among various biological species based upon similarities and
differences in their physical and genetic characteristics.
 It also is called a cladogram.

4. PHYLOGENY APPLICATIONS
 Tree of life:- Analyzing changes that have occurred
in evolution of different organisms.
 Phylogenetic relationships among genes can help
predict which ones might have similar functions.
 Follow changes occurring in rapidly changing
species.(eg,-HIV Virus)

5. TYPES OF PHYLOGENETIC TREE
 Rooted trees: a single node is designated as a common
ancestor ,a unique path leads from it through evolutionary
time to any node.
 Unrooted tree: only specify the relationship between nodes
say nothing about the direction in which evolution occured.

7. Constructing Phylogenetic Trees
There are three main methods of constructing phylogenetic trees:
* distance-based methods such as
UPGMA and neighbour-joining,
* parsimony-based methods such as maximum
parsimony, and
* character-based methods such as maximum likelihood
or Bayesian inference.

8. DISTANCE BASED METHODS
 Calculate evolutionary distances between sequences.
 Build a tree based on those distances.
 Calculate evolutionary distance between sequences and
make a matrix.
 So the evolutionary
Distances between the
Two sequences= 4

9. LIMITATIONS TO THE USE OF
TREES
 it is importance to remember that trees do have
limitations.for example, trees are meant to provide insight
into a research question and not intended to represented
an entire species history.
 several factors,like gene transfers,may affect the output
placed into a tree.
 all knowledge of limitations related to DNA degradation.

10. REFERENCES
 http:/www.natural.com/scitable/topicpage/reading-a-phyologenetic-tree-the-
meaning-meaning of-41956
 O’Hara , R. J Population thinking in tree thinking in systemstics.
 SlideServe.com ppt phylogenetic tree

11. Thank you