Transgenesis

Question 1

Transgenic animal:

Answer 1

An animal whose genome has been stably altered in ALL cells, including the germline

Question 2

Germ cells:

Answer 2

Egg and sperm. Transgenesis will result in ALL cells of the body having the edited gene

Question 3

Embryonic stem cells: (ES)

Answer 3

Undifferentiated cells of the early embryo (blastocyte). Have the ability to differentiate into any type of cell

Question 4

Induced pluripotent stem cells: (IPS)

Answer 4

Somatic cells that have been programmed to be like ES cells

Question 5

Chimera:

Answer 5

An animal containing cells from two different individuals

Question 6

Transgenesis vs. gene therapy

Answer 6

germ cells vs somatic cells
Permanent alteration vs stable or transient
Inheritable vs not
Not dine in humans vs done in humans

Question 7

When do we have access to the germline

Answer 7

The fertilized egg
Day 3.5 blastocyte

Question 8

What are the methods for producing transgenic animals

Answer 8

-Microinjection of DNA into fertilized egg or random insertion into ES (pronuclear injection)
-Gene targeting in ES or IPCs followed by injection into developing embryo
-Nuclear transfer from genetically altered cells (cloning)
-DNA editing w/ specific nucleases (CRISPR/CAS)

Question 9

Pronuclear injection-how to:

Answer 9

Transgene injected into fertilized egg
Embryos implanted in pseudopregnant animal

Question 10

How exact is pronuclear injection

Answer 10

Not very–the transgene is randomly inserted and expression level will vary based on the site of integration

Question 11

What are some drawbacks of pronuclear injection

Answer 11

Can disrupt endogenous genes
Can produce a loss of function phenotype

Question 12

What are some pros of pronuclear injection

Answer 12

can examine overexpression of a particular gene
Can examine in-vivo expression of a gene