Quantitative Genetics

Question 1

Complex trait

Answer 1

= trait that results from interplay of multiple factors (each with a small effect)

Question 2

Complex quantitative trait and examples

Answer 2

= metric or continuous heritable trait

Height, BP

Question 3

Do Quantitative traits follow Mendel’s law? Why?

Answer 3

Yes

individuals genes segregate according to mendelian ratios

effects are additive

Question 4

What is the formula for phenotypic variance?

Answer 4

Variation in your trait = Variation in genetic inheritance + Variation in environment

Vp = VG + VE

Question 5

What three components affect Genetic Variance and what are these?

Answer 5

Additive Variance (VA) = variation caused by particular allele

Dominance variance (VD) = caused by interactions between alternative alleles at locus

Epistatic/ interactive variation (VI) = caused by interactions between different alleles at different loci

Question 6

What is the formula for Genetic Variance?

Answer 6

VG = VA + VD + VI

Question 7

Heritability

Answer 7

proportion of phenotypic variation due to genetic variation

Question 8

Broad sense vs narrow sense heritability

Answer 8

B
all 3 sources of genetic variation ( all genetic factors)

N
only additive variation

Question 9

Concordance:

Answer 9

2 individuals how same trait/ disease

Question 10

What are identical and fraternal twins refereed to scientifically and how much of there genes do they share?

Answer 10

Identical = Monozygotic = share 100% of genes and same environment

Fraternal = Dizygoitic = share 50% of genes and same environment

Question 11

Regression

Answer 11

the tendency for offspring of parents with extreme differences in phenotype, to exhibit a phenotype that is the avg of 2 parental phenotypes

Question 12

Breeders Equation

Answer 12

H2 = R/S

R= response variable (difference of offsping to mean)

S= selection variable (difference of parents to the mean)

Question 13

differentiate between polygenic traits and multifactorial traits

Answer 13

polygenic = multiple genes cause the trait

multifactorial = environmental influences + one or more gene influences trait

Question 14

continuous complex variation

Answer 14

complex quantitative traits show much more variation, with a continuous range of phenotypes that cannot be easily classified into distinct categories)

Question 15

What percentage of people are within:
1 Standard Deviation
2 standard deviations
3 standard deviations

Answer 15

1- 68.26%
2- 95.44%
3- 99.73%

Question 16

In terms of correlation, what does a high r indicate?

Answer 16

a strong underlying relationship and a low variance

Question 17

What is the formula for heritability in twins?

Answer 17

h^2= 2(4mz - rdz)