Assignment

Evolution, Unit 2Mechanisms of Evolution

A. MutationB. Natural SelectionC. Genetic Drift

Three of the "architects" of the evolutionary synthesis:G. Ledyard Stebbins, Jr., George Gaylord Simpson, and Theodosius Dobzhansky, early 1970s.http://ucjeps.berkeley.edu/bryolab/babs/AJBarchitects.html

Mutation

Genetics Review:

1. Most of our genes provide instructions for building proteins.

2. The shape of the protein determines how it will function.

Genetics Review:

1. Most of our genes provide instructions for building proteins.2. The shape of the protein determines how it will function.

3. The amount of protein produced for a gene is about as important as the shape of the protein.

The amount of protein produced is critical to function…

A. The kinds of effects mutations can have on genes:

1. Silent mutations

2. LOF mutations

e.g., convergent loss of pigment in cave fish populations is caused by independently derived mutations that prevents the Oca2 gene from producing a functional protein (LOF mutations)

Protas et al., 2006, Nature Genetics

3. GOF mutations

e.g., sickling hemoglobin provides immunity to malaria parasiteOne nucleotide, one amino acid, very different proteins

4. Some mutations simply change the amount, timing, or location of protein produced.

Regulatory sequences and promoters (“switches”) control timing, location, and

quantity of transcription/protein production