Lecture 48. Complex Genetic Variation

Question 1

What is the main source of genetic variation used for research in experimental genetic models?

Answer 1

Artificial Mutation

Question 2

What is the main resource for translational genetics?

Answer 2

Natural Variation

Question 3

What are the names of the unusual traits in a species?

Answer 3

Discrete traits

Question 4

What is complete dominance?

Answer 4

Maximum expression in both AA and Aa with no expression in aa

Question 5

What is incomplete dominance?

Answer 5

Maximum expression in AA, intermediate expression in Aa and no expression in aa

Question 6

What is over dominance?

Answer 6

Intermediate expression in AA, maximum expression in Aa and no expression in aa

Question 7

What is full penetrance?

Answer 7

Maximum expression in both AA and Aa with no expression in aa

Question 8

What is partial penetrance?

Answer 8

Medium expression in AA, weak expression in Aa and no expression in aa

Question 9

What is the cause of primordial dwarfism?

Answer 9

Pericentrin gene mutations (PCNT)

Question 10

Are there any treatments for primordial dwarfism?

Answer 10

No

Question 11

What is the cause of genetic hypopituitary dwarfism?

Answer 11

Mutation in one of several genes (GHRHR, GH1)

Question 12

Are there any treatments for genetic hypopituitary dwarfism?

Answer 12

Yes, growth hormone therapy (somatotropin)

Question 13

What is the human growth hormone equivalent in plants?

Answer 13

Gibberellic acid (GA)

Question 14

How do dwarf mutants react to GA?

Answer 14

Some dwarf mutants are GA-responsive whilst others are not

Question 15

What is redundancy?

Answer 15

Duplicate genes that provide the same function

Question 16

What is the prediction if two pea varieties are bred together that share the same phenotype for flower colour and the first and second generation are all purple?

Answer 16

Both pea varieties share the same gene for flower colour

Question 17

What are complementary genes?

Answer 17

The phenotype depends on both genes being functional (e.g different steps in same biochemical pathway)

Question 18

What do Mendelian factors form the basis of?

Answer 18

The basis of quantitative (polygenic) traits

Question 19

What are the two methods used to map genes that underlie a phenotype on the basis of correlation with DNA sequence variation?

Answer 19

Linkage mapping population
Association mapping

Question 20

What is linkage mapping population?

Answer 20

Progeny derived from a controlled cross of known parents (chosen because they exhibit contrasting phenotypes and are polymorphic in many genome-wide DNA markers)

Question 21

What are the pros of recombinant inbred mapping population?

Answer 21

No questions of dominance
Immortal lines
Powerful data accumulation
Reproducibility
GxE experiment possible
Inter-mating inbreds, to test genetic models

Question 22

What are the cons of recombinant inbred mapping population?

Answer 22

Finite resource

Question 23

What does LOD stand for?

Answer 23

Logarithm Of the Odds

Question 24

What is an LOD score?

Answer 24

A statistical test for linkage

Question 25

What is the formula for LOD score?

Answer 25

log10(likelihood that two loci are linked/likelihood that two loci are unlinked)