L16 Quantitative Genetics

Question 1

Mendel’s principles of heredity

Answer 1

1. segregation of genes
2. independent assortment
3. dominance

Question 2

Quantitative variation

Answer 2

continuous

Question 3

Genetic basis of continuous traits

Answer 3

• segregation of multiple genes
• assortment depends on allele frequency
• dominance is not complete: difference in effect size

Question 4

Quantitative trait variation allows for a population of organisms a flexible response to

Answer 4

1. environmental variation e.g. temperature

2. change in selection regime e.g. disease, competition

Question 5

What does this mean in the context of genetic research?

Answer 5

• infer genotype from phenotype
• focuses on gene inducing variation rather than those fundamental to function
• natural variation in natural population

Question 6

Genetic effect

Answer 6

each genetic factor controlling a trait can be seen as independent elementary block: genetic effect

Question 7

Genetic value

Answer 7

All genetic effects add up to build the genetic value of a genotype which is an additive model of decomposition of the genetic effects

The genetic effects a genotype transmits to the next generation is called genetic value which factors allele frequency together with genetic effect

Question 8

Genetic variance

Answer 8

The amount of trait variation explained by genetic factors is called genetic variance

Question 9

Model for the linear decomposition of a trait

Answer 9

P = mu + G + E

P = mu + A + D + E

the effects are assumed independent

Question 10

Additive and dominance genetic effects

Answer 10

See onenote

Question 11

Variation induced by the environment

Answer 11

See onenote

Question 12

Variation induced by the genetic background

Answer 12

see onenote

• epistasis
• genetic x environment interactions

Question 13

Continuous traits are the result of multifactorial inheritance

Answer 13

1. involvement of multiple genes/loci
2. model for the linear decomposition of a trait
3. additive and dominant genetic effects
4. variation induced by the environment
5. variation introduced by genetic background

Question 14

The genetic value of a population

Answer 14

see onenote

• use values of genetic effects and frequencies of alleles
• the genetic value is the expected (average) value of a genotype relative to the mean of the population

Question 15

Genetic variance of a population

Answer 15

see onenote

• measures the proportion of a specific trait that is genetically determined for a specific population in a specific environment