Lecture 5: Prelude to lab II: Allelism File

Question 1

What do recessive mutations in humman voltage controlled sodium channel genes cause ?

Answer 1

Inducible and reversible muscle paralysis, are triggered by cold, high/low blood potassium and rest after exercise

Question 2

Recessive mutations in OCA2 gene can cause….

Answer 2

Blue eyes or albanism

Question 3

What is special about zellweger’s syndrome

Answer 3

Recessive mutations in any one of the 12 genes causes the same phenotype (genes encode subunits of peroxisome)

Question 4

Do mutations that result in the same phenotype always affect the same gene ?

Answer 4

Nope

Question 5

Do mutations that result in different phenotypes always affect different genes

Answer 5

Still nope

Question 6

Complementation test only works if…..

Answer 6

both mutations being tested are recessive

Question 7

What are the three steps to complementation testing

Answer 7

1. check if mutants are recessive
2. cross only the homozygous mutants
3. Look at F1 phenotype

Question 8

What does F1 phenotype results show us ?

Answer 8

If mutant = mutations DO NOT complement, therefore its the same gene

If WT= mutations DO complement, must be different genes

Question 9

What happens when a dominant mutation is involved in testing ?

Answer 9

Test fails, as all F1 will show mutant

Question 10

What type of medium can yeast grow on ? why?

Answer 10

minimal medium, they only need source of C,N,P, trace metals and vitamins. They are able to manufacture all complex building blocks (amino acids, nucleosides)

Question 11

What type of medium can auxotrophs grow on ? why?

Answer 11

Supplemented medium (e.g. MM + histidine), need C,N,P, trace metals and vitamins but cannot form end product of metabolic pathway without added supplement

Question 12

What medium does a His- auxotroph need ?

Answer 12

MM + histidine

Question 13

What medium does a Ade- auxotroph need ?

Answer 13

MM + Adenine

Question 14

What are the steps for plating out a culture ?

Answer 14

1. organisms are grown in liquid nutrient medium
2. Diluted and spread on agar
3. each organism grows into colony

Question 15

What do colonies represent ?

Answer 15

A colony contains progeny (passed down info) derived from a single original cell

Question 16

What is a complete medium ?

Answer 16

MM with every known useful additive

Question 17

If you are unable to do complementation test (dominant mutation), what do you do?

Answer 17

Work out an inheritance pattern (Mendels stuff ugh)

Question 18

If mutations are in different genes what cross must be used ?

Answer 18

Dihybrid cross

Question 19

How do you analyse F2 progeny ?

Answer 19

NO WT in F2= mutations in the same gene

Some WT in F2= Mutations in different genes