Lecture 25

Question 1

How do we get information about the function of a gene from its phenotype?

Answer 1

• study organisms with natural variant
• when no natural variant, can make own

Question 2

How do we use genetic techniques to find out
what a gene does?

Answer 2

• study natural variant
• increase rate of mutation

Question 3

What is transgenesis?

Answer 3

Taking gene of interest, copying, then inserting into another organism

Question 4

What is targeted
mutation/gene knockout/reverse genetics?

Answer 4

Deliberately breaking a gene.

Question 5

What are the three main model organisms used to make into mutants? Why are they used?

Answer 5

• mice
• zebrafish
• drosophila (fly)
• used as easy to manipulate + raised in controlled environment

Question 6

What are the components of a Cas-9 guide RNA complex?

Answer 6

• Cas-9 protein which has active sites that can cut DNA
• guide RNA with complementary sequence for target gene

Question 7

How does CRISPR-Cas9 work?

Answer 7

• get Cas-9 guide RNA complex in target cell
• Cas9 enters nucleus and finds target sequence
• Cas9 breaks double stranded DNA at target site
• in absence of template, DNA repair enzymes try to fix (often leads to errors)
• if repair template available, can make gene edit

Question 8

What are three parent babies?

Answer 8

• mother has disease related to mitochondrial DNA
• take her eggs nucleus and put in donor egg