LECTURE 3

Question 1

S

Answer 1

strength of selection

Question 2

If a dominant trait is being selected for fitness values?

Answer 2

AA=1 Aa=1 aa=1-s

Question 3

Selection for a recessive trait effect on fitness

Answer 3

AA=1 Aa=1-s aa=1-s

Question 4

Selection for codominance effect on fitness of genotypes

Answer 4

AA=1 Aa=1-1/2s aa=1-s

Question 5

Overdominance selection effect on fitness if genotypes?

Answer 5

AA=1-s11 Aa=1 aa=1-s22

Question 6

Heritability is used to ?

Answer 6

Estimate the volume variation in a trait that is genetic

Question 7

Phenotypic variation?

Answer 7

total amount of variation for a trait among individuals

Question 8

Components of phenotypic variation?

Answer 8

• genetic variation
• environmental variation
• Genotype, environment, interaction variance (added all together)

Question 9

Components of genetic variation?

Answer 9

• additive genetic variation
• Dominant genetic variation
• gene interaction variation (added altogether)

Question 10

Heritability equation

Answer 10

h^2= phenotypic variance/ genotypic variance

Question 11

Narrow sense heritability definition and equation?

Answer 11

The proportion of the phenotype in which the parents contribute
Additive variance from parents / phenotypic variance

Question 12

Regression definition ?

Answer 12

-Predicting the value of one variable if given another

Question 13

recession coefficient?

Answer 13

gradient of the regression line, change in phenotypic variance on average
-Represented by the letter b

Question 14

Regression is usually a ?

Answer 14

Line of best fit

Question 15

Regression plotted against?

Answer 15

Phenotype of offspring (y) against “ parent (x)

Question 16

If there is a large regression coefficient value

Answer 16

Parental phenotype is strongly positively correlated with the offspring

Question 17

Genetic coronations can be due to?

Answer 17

Linkage disequilibrium or pleiotropy

Question 18

Linkage disequilibrium?

Answer 18

tends to be found when alleles at different loci within a chromosome are inherited together and are less effected by crossing over/ recombination.
-Over representation of either coupling gametes or repulsion gametes= linkage disequilibrium

Question 19

If there are just coupling gametes ?

Answer 19

genetic correlation

Question 20

Alleles completely linked?

Answer 20

No crossing over, have same genotype as parent, no new gamete combinations formed

Question 21

repulsion gamete is due to?

Answer 21

recombination occurring to produce new gamete combinations

Question 22

pleiotropy

Answer 22

formation of multiple traits from one single gene,

Question 23

Two techniques to identify loci which are impacting a complex trait

Answer 23

QTL’s and GWAS (gene wide association studies)

Question 24

QTL’s don’t necessarily detect ?

Answer 24

genes

- often not associated in proteins but gene expression

Question 25

QTL’s use ?

Answer 25

Genetic markers & identify causal relationships linked to a locus

Question 26

QTL’s graphs are bell curves but separate to each other

Answer 26

Genetic marker is strongly associated with trait value

Question 27

GWAS

Answer 27

testing whether groups with different phenotypes have different frequencies of alleles at a locus

Question 28

As LOD scores increase?

Answer 28

significance of loci increases too

Question 29

GWAS doesn’t necessarily need ?

Answer 29

markers, can detect in dense sequence data