W8L2 Gene drive

Question 1

How does mouse t haplotype work

Answer 1

-in the t-haplotype contain antidote and toxin.
-the toxin are able to diffuse to other cell causing WT spree to die
-furthermore, found o chromosome 17, inverted region so suppressed recombination

Question 2

Homing endonucleases

Answer 2

-enzyme that induce double stranded DNA breaks at specific, long (and rare) target sequences in the genome

Question 3

Cas9

Answer 3

DsDNA break induced by Cas9 is directed by a 20 base guide RNA(gRNA) that matches the target sequences

Question 4

Laboratory gene drive demonstration

Answer 4

-Targeting a female fertility gene results in bias toward male offspring that carry the gene drive
-initial pop of 300 equal sex ratio. Population crash start at the eight generation

Question 5

Zebra fish split gene drive for optimizing gene drive design

Answer 5

-Aromatase enzyme converts testosterone to estrogen
-cyp19a1a -/- cause female to male sex reversal
-as bio security precaution, essential elements of the gene drive are split into unlinked part of the genome

Question 6

Inserting gene drive into non-model species

Answer 6

-for European carp and cane toad: direct injection of CRISPR reagent into egg
-for mammals: nuclear transfer of CIRSPER edited cell

Question 7

Problem of spatial heterogeneity

Answer 7

-gene drive chasing the Wildtype alleles

Question 8

The problem with generation time

Answer 8

-different animal have different generation time, the longer the generation time is, the longer gene drive fixation process will be (time to eradicate )

Question 9

Solution to the risk of introducing gene drive to a non target population

Answer 9

-simple to engineer a gene drive resistant allele compare to the gene drive itself
-this resistance can cause the gene drive allel to extinction

Question 10

Risk of gene drive resistance

Answer 10

-resistance can be induced, de novo or preexisting in the population
-solution: incorporate multiple gRNA modules into the gene drive

Question 11

example of gene editing wildlife

Answer 11

-American chestnut tree with transgene for chestnut blight resistance- (not approved)
-northern quolls with small gene edit for resistance to cane toad toxin- inprogress
-frog with transgene for skin secreted neutralizing antibody against chytrid funguses-in progress
-thylacine de-extinction in progress