241 - 39 & 40, Quantitative Genetics

Question 1

______ traits are traits determined by several genes acting together

Answer 1

complex

Question 2

Complex traits are often ______ and influenced by environmental factors

Answer 2

polygenic (traits influenced by multiple genes)

Question 3

complex traits are _______, meaning having many factors, not only genetic ones

Answer 3

multifactorial

Question 4

Complex traits can be _______ (continuously varying) or _____ (all-or- nothing)

Answer 4

quantitative (continuously varying) or threshold (all-or- nothing)

Question 5

In complex traits, individual genes are called _______ ______ ____ (___)

Answer 5

quantitative trait loci (QTL)

Question 6

In quantitative traits, the relative role of environment and genetics can be determined by looking at the variation in phenotype between genetically _____ organisms as compared to genetically more ______ organisms

Answer 6

pure; diverse

Question 7

In determining role of env. and genetics, any variation in genetically pure organisms is due to ________

Answer 7

environment

Question 8

In determining role of env. and genetics, the extra variation in genetically ______ organisms is due to the variability in the genes

Answer 8

diverse

Question 9

st dev is related to variance how

Answer 9

v^2 = variance
v = st dev
(a.k.a., st dev is square root of variance)

Question 10

broad-sense heritability equation

Answer 10

H^2 = V_g / V_P

Question 11

narrow-sense heritability equation

Answer 11

h^2 = V_a / V_P = R / S

Question 12

difference between broad-sense and narrow-sense

Answer 12

broad is - genetic diff. / total variance

narrow is - additive variance / total variance

Question 13

total genetic variation equation

Answer 13

V_g = V_d + V_i + V_a

Question 14

V_g, V_d, V_i, V_a stand for . . .

Answer 14

V_g - total genetic variance
V_d - dominance variance
V_i - epistatic variance
V_a - additive genetic variance

Question 15

R, S stand for

Answer 15

response, selection

Question 16

________ traits are polygenic traits in which the phenotype is recorded by counting whole numbers. They are quantitative traits but do not have an infinite range of phenotypes.

Answer 16

Meristic

Question 17

_______ traits are polygenic and often multifactorial but have a small number of discrete phenotypic classes

Answer 17

Threshold

Question 18

example of meristic trait

Answer 18

of peas in a pod

Question 19

example of threshold traits

Answer 19

of predisposing alleles in genotype of clinical diabetes

Question 20

_______ ______ contribute to a single quantitative character, and the phenotypic contribution of each additive allele is approximately equa

Answer 20

additive alleles

Question 21

number of genes (n) contributing to a quantitative trait can be estimated based on the ratio of ___ individuals resembling either of the two extreme P1 phenotypes

Answer 21

F2

Question 22

equation for determining # of genes contributing to a quant. trait

Answer 22

1 / 4^n = ratio of F2 individuals expressing either extreme phenotype

Question 23

1 / 4^n = ratio of F2 individuals expressing . . .

Answer 23

other extreme phenotype

Question 24

total phenotypic variance

Answer 24

V_p = V_g + V_e + V_eg

Question 25

Meaning of:
V_p
V_g
V_e
V_i

Answer 25

V_p - phenotypic
V_g - genetic
V_e - environmental
V_eg - envi./genetic