Lecture 21: Biotech and Modern Agriculture - 11/27

Question 1

What are the fixed locations on which genes are located called?

Answer 1

Locus (plural: loci)

Question 2

Mutation breeding

Answer 2

Exposing seeds to chemicals or radiation to induce new genetic mutations

Question 3

Somaclonal variation

Answer 3

Genetic changes that occur during in vitro tissue culture

Question 4

What are the three things plant breeding requires?

Answer 4

Fertile plant parents
Availability of populations with beneficial traits
Many generations of back-crossing

Question 5

Linkage drag

Answer 5

When genes that are linked to the gene of interest tag along during introgression

Question 6

Hybrid vigor

Answer 6

Some traits need to be heterozygous

Question 7

Introgression

Answer 7

The transfer of genetic information from one species to another as a result of hybridization between them and repeated backcrossing

Question 8

Biotechnology

Answer 8

Any process that involves the application of:

in vitro nucleic acid techniques (including recombinant DNA, for example)

fusion of cells (overcoming natural physiological reproductive barriers)

Question 9

“in vitro” meaning

Answer 9

A procedure performed outside of a living organism and in an artificial environment

For example, performing gene modification on a cell inside a test tube would be considered in vitro

Question 10

Genetic engineering

Answer 10

Allows for the modification of the plant’s genome by means other than conventional breeding, genetic mutations, or tissue culture

Question 11

Transgenic organisms

Answer 11

Plants containing the DNA of another organism

Question 12

How has the cost of DNA sequencing changed over the past 20 years?

Answer 12

It has decreased significantly

Question 13

What are the three main methods used to introduce DNA fragments into a plant’s genome?

Answer 13

Chemically-mediated transfer
Physically-mediated transfer
Vectors

Question 14

Protoplasts

Answer 14

Cells without a cell wall

Question 15

Chemically-mediated transfer

Answer 15

Make protoplasts (cells w/o cell wall) by degrading cells’ cell walls with a mixture of polysaccharide-degrading enzymes

DNA uptake is enhanced by chemical treatments which reversibly stabilize the plasma membrane so it’s permeable to DNA

A whole plant is regenerated from that protoplast

Question 16

What are the three methods of physically-mediated transfer?

Answer 16

Biolistic transformation
Microinjection
Electroporation

Question 17

Biolistic transformation

Answer 17

Using a gene gun to shoot gold/tungsten particles coated with DNA fragments into a plant tissue

Cons: inefficient

Question 18

Microinjection

Answer 18

Transfer of a gene through a micropipette into the cytoplasm or nucleus of a plant protoplast

Cons: this method is slow, expensive, and highly skilled

Question 19

Electroporation

Answer 19

Using a pulse of electricity to temporarily create pores in the plant membrane, through which DNA can be introduced

Cons: can damage cells, resulting in death

Question 20

Agrobacterium-mediated transfer (vector)

Answer 20

Transferring a gene of interest without causing disease

Cons: not all plants are susceptible to agrobacterium infection, and not all agro-susceptible plants can be regenerated from a single cell

Question 21

What are the challenges of commercializing GM crops?

Answer 21

They take a lot of money and time to commercialize

Question 22

What new technology can be considered the future of plant biotechnology?

Answer 22

Using “molecular scissors” (CRISPR/Cas) that can create double-stranded breaks at precise locations