How To Read A Phylogenetic Tree

Question

[User 0063]

Hi, I'm a newbie. Could you kindly help me to read the tree below?

[Thaman]

It's really hard to understand what you mean by just reading phylogenetic tree. Can you be more specific like reading their distance or how evolutionary they are related?

[Pierre Lindenbaum]

sounds like a homework question

[User 0063]

I mean how the sequence are related evolutionary

Answer 1

[Thaman]

Phylogenetic tree is the potray of the evolutionary relationship between the organisms which helps in understanding biodiversity. Taxonomy is the classification of the organisms. Tree consists of taxa which can be basically a rooted (known common ancestor) and unrooted (typical with unknown common ancestor). Tree can be rooted by outgrouping them. You can understand basic tree terminilogy from below figure.

Analysis

• Multiple Sequence Alignment either nucleotides, DNA or Protein
• DNA may change but protein remains the same during the course of evolution

Method of analyzing tree

• Distance Methods
  
• Parsimony Methods
• Maximum Likelihood
  
• Bayesian Approaches
• Reliability Tests

For detail understanding please go through the given link :- http://www.ncbi.nlm.nih.gov/Class/NAWBIS/Modules/Phylogenetics/phylo2.html

Answer 2

[Michael Schubert]

Please show us that you have taken some effort to find the answer yourself before posting a question here.

For instance, have you read the Wikipedia article on phylogenetic trees? Especially the first couple of lines are often tremendously useful if you don't understand the topic at all.

In a rooted phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of the descendants, and the edge lengths in some trees may be interpreted as time estimates.

So basically, the shorter the path between two nodes is, the more closely they are related. The one thing you have keep in mind is that usually only the horizontal axis is interpreted as time, the vertical is only there to make the trees readable.

Answer 3

[Dave Lunt]

Dear "unknown (Google)", I agree with the others that you need to put more effort into asking questions clearly and specifically. In all areas of science asking good questions is difficult, but is a major step in clarifying the problem for yourself and finding the answer. Whatever it is exactly you're looking for this publication might help.

TR Gregory (2008) Understanding Evolutionary Trees. EVOLUTION: EDUCATION AND OUTREACH Volume 1, Number 2, 121-137, DOI: 10.1007/s12052-008-0035-x