Chapter 6: Exploring Evolution and Bioinformatics

Question 1

Molecular evolution

Answer 1

study of how proteins, nucleic acids and other molecules have changed through time.

Question 2

What makes a molecule homologous ?

Answer 2

If they are derived from a common ancestor and later diverged from this ancestral sequence.

Question 3

What are the two types of homology ?

Answer 3

Paralogs: homologs that are present within one species

Orthologs- Homologs that are present within different species and have very similar functions

Question 4

In How can Homology be detected ?

Answer 4

It can be detected by significant sequence similarity resulting in a common 3D structure.

Question 5

What are examples of a ortholog?

Answer 5

Bovine and Human ribonuclease

Question 6

What are examples of a paralogs?

Answer 6

Human ribonuclease and angiogenin

Question 7

In what regions of similarities are sequences aligned ?

Answer 7

In the specific amino acid sequence or in the physical character of the amino acids.

Question 8

Why is a Gap needed in sequence alignments?

Answer 8

allows all regions of similarity to be included

in the alignment and because one protein has evolved to either gain or lose an amino acid.

Question 9

Convergent Evolution

Answer 9

When two unrelated proteins (not descended from a common ancestor) evolve to form the same structure and/ or function

Question 10

Evolution can be done in a test tube using RNA as a model system. Why is RNA used as a selectable traits ?

Answer 10

It has both catalytic and binding affinities

Question 11

What are the process of Evolution in a Test Tube ?

Answer 11

1. Mutagenic PCR in the presence of manganese ions will generate mutant DNA molecules.
2. In vitro transcription using T7 RNA polymerase to generate the pool of mutant RNAs
3. Select for binding affinity or catalysis (ATP)
4. Reverse transcription of selected members back into DNA.