Complications with mutant hunts

Question 1

What are 5 complications with mutant hunts?

Answer 1

Incomplete pentrance, variable expressivity, pleiotropy, lethal mutations, lack of phenotype

Question 2

What is incomplete penetrance?

Answer 2

An individual with a given genotype doesn’t display the corresponding phenotype

Question 3

How does incomplete penetrance complicate a mutant hunt?

Answer 3

The individual isn’t showing the mutant phenotype, so it doesn’t end up getting chosen in a screen

Question 4

What is variable expressivity?

Answer 4

Individuals with a given genotype show a phenotype, but the severity is along a spectrum

Question 5

What is pleiotropy?

Answer 5

A mutation affects more than one characteristic

Question 6

What might cause a lack of phenotype?

Answer 6

Multigene families, genetic networks, not seen under tested conditions, barely noticeable, functions are only required every few generations

Question 7

How do multi-gene families cause a lack of phenotype?

Answer 7

A mutation might knock out one gene, but it gets compensated for by the rest of the family. We need to knock out the entire family to get a phenotype

Question 8

How do genetic networks cause a lack of phenotype?

Answer 8

Other pathways can be rerouted to compensate for a mutation by bypassing a blocked step through another pathway