pi_lec4 - 20.181 Lecture 4 Contents 1 Review of Homework #1...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
20.181 Lecture 4 Contents 1 Review of Homework #1 2 Parsimony Continued o 2.1 Down-Pass Algorithm 3 Sankoff Downpass Algorithm Review of Homework #1 1. Fibonacci question o Using recursion is good with Fibonacci if you're returning (and passing) a list. 2. Parsimony: o Review of how to assess the most parsimonious explanation of nodes' states. o Solution/notes on the Parsimony question. Parsimony Continued Why parsimony? o we can suggest infinite alternative explanations involving increasing numbers of mutations but they become less and less plausible o this algorithm is sometimes called "model-free" because the model is implicit o is parsimony better than just an extreme case of maximum likelihood? This is still debated. One not -optimal way to look for the most parsimonious tree: try all four possibilities at every node. But that would require looking at 4^n possibilities! Using recursion in this problem, we can avoid that.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

pi_lec4 - 20.181 Lecture 4 Contents 1 Review of Homework #1...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online