L18 - quantitative genetics + multifactorial traits

Question 1

what are polygenic traits

Answer 1

traits influenced by many genes

eg eye colour / hair

Question 2

what is quantitative inheritance

Answer 2

quantifying continuous variation

from polygenic traits

Question 3

when is correlation coefficient used?

Answer 3

to calculate how one trait affects another

Question 4

what does a +ve correlation coefficient tell us

Answer 4

that an increase in 1 trait causes an increase in the other

Question 5

what do we use heritability equation for

Answer 5

to calculate how much of phenotype variation is due to genetic/environment

Question 6

what does a heritability value close to 1 tell us?

Answer 6

environment has little effect on phenotype

Question 7

what does a heritability value close to 0 tell us?

Answer 7

genes have little effect on the phenotype

Question 8

what does concordant mean in twin studies

Answer 8

both twins have trait

Question 9

what does discordant mean in twin studies

Answer 9

only 1 twin has trait

Question 10

what does it mean if concordance in a twin study is greater in MZ twins than DZ twins?

Answer 10

strong genetic influence

Question 11

limitations of twin studies

Answer 11

1. MZ may not be 100% identical as genotypes can diverge slightly after split
2. gene expression patterns can change with age