Module 2: Lecture 7

Question 1

What does the source population become after transmission?

Answer 1

The source population becomes paraphyletic

Question 2

What does a paraphyletic tree or a nested tree with 2 different populations indicate?

Answer 2

This indicates a transmission event. If population 2 is nested within population 1, this indicates population 1 was the source and transmitted it to population 2

Question 3

Is transmission always directly from one patient to another?

Answer 3

No, there could be intermediates

Question 4

True or false: Paraphyly of the source population tends to be lost over time and become monophyletic

Answer 4

True

Question 5

Name 2 reasons why different genes have different phylogenies?

Answer 5

1. Phylogenies can differ between different samples
2. Recombination

Question 6

True or false: when the true relationship between populations is paraphyletic, it may appear monophyletic

Answer 6

True

Question 7

True or false: when the true relationship between populations is monophyletic, it may appear paraphyletic in the sample

Answer 7

False

Question 8

What does a nested relationship between 2 populations indicate?

Answer 8

Migration/transmission event

Question 9

What does the out group of a nested tree mean

Answer 9

The source

Question 10

What 2 things are important when trying to prove transmission between 1 population to another in a phylogenetic tree

Answer 10

1. At least 2 relatives in the source population
2. The 2+ relatives cannot be more closely related to each other, than one of them is to the other population