L29 Quantitative traits to fitness

Question 1

Gene-environment interactions

Answer 1

see onenote

Occur when genetic differences depend on the environment

In QG typically detected through “crossing” pattern in strain

Question 2

Crossing pattern

Answer 2

common for fitness traits and can indicate local adaptation

reciprocal transplant experiment

Question 3

Interactions among genes

Answer 3

• affects multiple traits
• result of pleiotropy = one gene, effects more than one trait
• pleiotropy norm rather than exception

Measured by traits being genetically correlated
-1 = negatively associated
+1 = positively associated

Genetic correlation = statistic equivalent of pleiotropy

Question 4

Genetic correlations lead to correlated selection responses

Answer 4

e. g. selection for longevity
- negative correlation between lifespan and early reproduction
- evolutionary explanation for why aging occurs based on pleiotropy

• Why we don’t live forever due to genetic correlation, due to pleiotropy
• Aging occurs because of pleiotropy, genetic correlation

Question 5

Evolution in the lab

Answer 5

see onenote

“old flies”

Question 6

Genetic correlations commonly detected for traits that are under selection

Answer 6

e.g. reproduction, predator avoidance, competition often show correlations with each other and other traits

• means an understanding of selection depends on considering multiple traits
• based on concept of fitness depending on multiple traits
• genetic correlations and heritabilities combine to dictate the extent to which traits in these surfaces change under directional selection

Question 7

Trait correlations often shown as matrix with heritabilities

Answer 7

see onenote

Question 8

Quantitative traits and fitness

Answer 8

see onenote

single trait vs multiple traits

How does the value of the trait change with fitness?

Question 9

Single trait and fitness

Answer 9

see onenote

Question 10

Multiple traits and fitness

Answer 10

see onenote

complicated prediction

e.g. weight vs beak wdith