Chapter 17.1: Creating Transgenic Organisms

Question 1

What are 3 ways to introduce transgenes?

Answer 1

 Subjected to treatments that disrupt the cell wall, and DNA can enter the cells in a fashion similar to the artificial transformation of E. coli
 Injection of a DNA directly into a cell or embryo
 Transgenic DNA can be incorporated into a virus particle or even a bacterium that can then infect a cell

Question 2

What does o Cell that contain the transgene must have the ability to develop into gametes mean for animals and plants?

Answer 2

 In animals, this requirement means that the transgene must be incorporated into a germ-line cell
 In plants, almost any cell can carry the transgene because entire plants can be regenerated from isolated cells

Question 3

What is o A vector derived from the tumor-inducing (Ti) plasmid of the bacterium Agrobacterium tumefaciens is the basis for an efficient method for introducing transgenes into plants?

Answer 3

agrobacterium-mediated T-DNA transfer

Question 4

What are P elements?

Answer 4

o	P elements are a class of DNA transposon in Drosophila
	Autonomous P elements contain a gene for transposase protein, and the transposon ends are inverted repeats
	Transposase binds the inverted repeats, cuts the transposon out of the genome, and “pastes” it into a new location

Question 5

Describe the method of pronuclear injection to generate transgenic mice

Answer 5

 Several zygotes are recovered from sacrificed female. Zygotes transferred to a depression slide containing culture medium. DNA is injected into the pronucleus of the zygote. Several tandem copies of injected DNA integrate into a random location on a chromosome. Several injected embryos are placed into oviduct of receptive female. Mice that were injected as embryos are born. Their tail cells are tested for the presence of injected DNA

Question 6

Describe how agrobacterium-mediated T-DNA transfer accomplish plant transgenesis

Answer 6

 Researchers infect plants with Agrobacterium tumefaciens bacteria containing two plasmid constructs. A T-DNA plasmid contains a transgene and marker gene that confers resistance to a herbicide, both within the T-DNA ends of LB and RB. A helper plasmid contains the vir genes, required for T-DNA transfer to a plant cell. Upon infection, the recombinant T-DNA integrates into the host plant genome. Investigators select from single cells with a transgene insertion by growing cells in the presence of herbicide. They then grow the selected cell into a whole transgenic plant.

Question 7

o Cell that contain the transgene must have the ability to develop into what?

Answer 7

gametes

Question 8

Describe P element transformation in Drosophila

Answer 8

 A transgene is first ligated into a vector containing the white+ gene (w+; marker gene) located between P element inverted repeats. Researches inject this plasmid, along with a helper plasmid containing the P element transposase gene into w- host embryos where transposition occurs in some germ-line cells. When adults with these germ cells are mated with w- flies, some progeny will have red eyes and an integrated transgene
• The marker gene enables detection of transgenic flies

Question 9

Define agrobacterium-mediated T-DNA transfer

Answer 9

o A vector derived from the tumor-inducing (Ti) plasmid of the bacterium Agrobacterium tumefaciens is the basis for an efficient method for introducing transgenes into plants

Question 10

What is a transgenic organism?

Answer 10

• A transgenic organism is one whose genome contains a gene from another individual of the same species or a different one