Topic 9: Deextinction

Question 1

What are the goals of de-extinction? Why do we do it?

Answer 1

• Because we can do it scientifically
• increase genetic diversity if we have lost a population
• fill a niche in an environment
• moral obligation

Question 2

What are the three types of de-extinction techniques

Answer 2

1. back-breeding
2. cloning
3. genetic engineering

Question 3

What is back breeding

Answer 3

• type of de-extinction technique
• takes traits in populations and selectively breeds to try and bring back a species
• selects individuals by phenotype or genotype, controlled crosses.

Question 4

What are the benefits and limitations of back-breeding?

Answer 4

benefits:
- no special technology needed
- long history of quantitative genetics, have done this for a long time

Limitations:
- still need the traits/phenotypes to exist in the population
- no guarantee that traits will be maintained if breeding control stops/ random mating begins
- small populations could lead to inbreeding, increase in drift, ect.

Question 5

What is cloning?

Answer 5

• type of de-extinction technique
• somatic cell nuclear transfer, taking a tissue sample from an organism, extracting nucleus, taking denucleated egg from a donor species and putting the nucleus in this egg, develops ect.

Question 6

What are the benefits and limitations of cloning?

Answer 6

Benefits:
- creates an exact copy of DNA
- faster than back-breeding
- recent history of applying the method

Limitations:
- no guarantee of success
- no genetic variation
- genetic damage/baggage of OG sample copied into clone, causing decreased lifespan
- doesn’t work for all species (no egg laying species)
- needs living nucleus cells
- need closely related donor species for surrogate

Question 7

What is genetic engineering?

Answer 7

• type of de-extinction method
• genome of extinct species is sequenced, differences between extinct species and living relatives are found, ‘edit’ genome of living species to match the extinct one, and finally implant edited genome into donor egg

Question 8

What are the benefits and limitations to genetic engineering?

Answer 8

benefits:
- creates more genetic diversity than cloning
- builds onto methods for somatic cell nucleus transfer
- doesn’t require living/viable cells of extinct species

Limitations:
- need subfossil to genome sequence, which is location dependent
- need a living relative
- very hard to edit multiple genome sequences, and to determine which areas are important to edit

Question 9

what are some biological considerations for de-extinction?

Answer 9

• genotype/phenotype may not be controlled entirely by genetics, they have environmental influence. This would effect back-breeding
• founder effects. If we de-extinct a species, we are intentionally bottlenecking it, with so few starter founders.
• the need for ongoing management

Question 10

What are major ethical considerations for de-extinction?

Answer 10

• has the natural environment changed since the species lived?
• has the underlying problem that led to extinction been addressed?
• is it ethical to have small populations? socially and genetically?
• could the money be better spent elsewhere, as cloning/genetic engineering is expensive?
• who is making these decisions? who is being consulted?

Question 11

What makes mammoths a good cloning species?

Answer 11

• many mammoths preserved- because of the colder locations they lived in
• many samples, so prevention of bottleneck occurring
• b/c we have so many mammoths, we can look at the genetic diversity of them at many different time periods
• current living relative species