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Flashcards in Heritability Deck (23):
1

Discrete Traits (Definition and list two examples)

Traits in which only one or a couple of genes determine the trait. An example is eye color and pea plant texture (wrinkled or smooth). Usually have two alleles determining trait within the gene.

2

Continuous Traits

Traits determined by numerous genes (and thus numerous alleles). Example include height, hair color, obesity

3

What two components make up the phenotype of an individual?

Genes and enviroment

4

Polygenic Traits

Traits determined by more than one gene (usually continuous)

5

What causes continuous variation?

The combination of the effects of genes and environment

6

In which case is it easier to predict genotype from phenotype in terms of genes and the environment?

Easiest to predict when environment is having very little effect on expression of the genes

7

Vp

Total phenotype variation

8

Vg

Variation from differences in genetic factors

9

Ve

Variation from environment

10

VgXe

Variation due to the interaction between genes and environment

11

Heritability Equations

Vp=Vg+Ve+Vgxe
h^2=Vg/Vp

12

Heritability in own words:

The genetic variation in a population accounted for by genes

13

What tests is used to discover heritability?

An ANOVA to compare differences in variation and regression to compare parents to offspring

14

How are regression lines used in twin studies?

To compare a trait in one twin to a trait in the other twin and analyze the slope

15

What does rMZA represent?

The correlation coefficient of a certain trait among monozygotic twins

16

Correlation equation for rMZA?

=Vg+Ves/ Vt

17

What is special about Ves in the correlation equation?

It is negligible because the twins are said to be reared in different locations with different enviroments

18

What does the Ves negligible assumption lead to?

Overestimate in heritability because although twins weren't reared together, they may have shared similar enviroments

19

4 Criticisms of Twin Studies

1)Ignored shared environment in identical twins or unshared environment in twins raised together
2) Mono-zygotic twins not genetically identical
3)Twins are NOT a random sample of population
4)Twins could seek out same niche based on SMALL number of genetic similarities

20

What is the misassumption regarding what heritability measures?

Not a measure of genetic control within an individual, but the extent to which genetic differences among individuals within the population influence the trait

21

Genome Wide Association Study

Measures the association between SNP's in population and phenotype and looks at the function of genes associated with those SNPS determining phenotype

22

What is the reason for missing heritability in the GWAS?

We do not have the entire genome for each patient so some of the variation is not captured in the SNP's

23

What kind of SNP's will you have if you have a common disease with a common variant?

Many small effect SNP's