Flashcards in Lecture 2: Quantitative Genetics 1 Deck (11):

1

## Define 'quantitative genetics'.

### The study of the genetic and environmental components of traits that vary continuously.

2

## Define 'qualitative traits' and give examples.

### Difference between phenotypes of two individuals can be explained by the difference in genotype at a small number of loci i.e. 1 or two e.g. blood groups, cat coat colour, colour vision.

3

## Define 'quantitative traits' and give examples.

### Phenotypic difference between individuals is due to difference in genotype at a large number of loci e.g. weight, height.

4

## What is the phenotypic variance dependent on?

### Phenotypic variance = genetic variance + environmental variance.

5

## What is genetic variance dependent on?

### Genetic variance = additive genetic variance + dominance genetic variance + epistatic genetic variation.

6

## What are the problems with predicting the evolution of quantitative traits?

###
- Dominance

- epistasis

- environmental effects.

7

## Define 'heritability' and give its equation.

### A measure of the degree of resemblance between relatives. H squared = additive genetic variance/ phenotypic variance. OR H squared = additive genetic variance/ (genetic variance + environmental variance).

8

## What is the 'breeder's equation'?

###
R = h(squared) x S

R = response to selection

h = heritability

S = selection differential.

9

## What is epistatic genetic variance?

### Variation due to interactions among loci.

10

## Define 'polygenetic inheritance'.

### A trait is determined by a large number of different genes (resulting in high variation).

11