module 14

Question 1

complex traits

Answer 1

characteristics that are determined by several genes and are significantly influenced by environmental factors

Question 2

meristic traits

Answer 2

can be expressed in whole numbers

Question 3

threshold traits

Answer 3

traits that are inherited due to the contributions of many genes

Question 4

frequency distribution

Answer 4

trait is divided arbitrarily into a number of discrete phyenotypic categories

Question 5

normal distribution

Answer 5

traits of interest varies ina symmetrical way around an average value

Question 6

covariance

Answer 6

the degree of variation between two variables within a group

Question 7

correlation coefficient (r)

Answer 7

the strength of associations between two variables

Question 8

polygenic

Answer 8

influenced by two or more genes

Question 9

polygenic inheritance

Answer 9

the transmission of traits that are governed by two or more genes

Question 10

quantitative trait locus (QTL)

Answer 10

the location on a chromosome that harbors one or more genes that affect the outcome of a quantitative trait

Question 11

Vg

Answer 11

Genetic variance

Question 12

Ve

Answer 12

environmental variance

Question 13

Vp = Vg + Ve

Answer 13

1. genetic and environmental factors are the only two components that determine a trait
2. these factors are independent of one another

Question 14

if Vg is high and Ve is low then

Answer 14

genetics is more important in promoting phenotypic variation in a population

Question 15

if Ve is high and Vg is low then

Answer 15

the environment causes much of the phenotypic variation in a population

Question 16

genotype-environmental interaction

Answer 16

genetics and environment interact to affect a trait

Question 17

genotype-environment association

Answer 17

when certain genotypes are preferentially found in a particular environment

Question 18

heritability

Answer 18

the amount of phenotypic variation within a group of individuals that is due to genetic variation

Question 19

when heritability = 1

Answer 19

all the phenotypic variation in a group is due to genetic variation

Question 20

when heritability = 0

Answer 20

all the phenotypic variation is due to environmental factors

Question 21

hb^2

Answer 21

= Vg/Vp

Question 22

Vg (equation)

Answer 22

= Va(additive) + Vd(dominant/recessive) + Vi(interact)

Question 23

narrow sense heritability

Answer 23

the heritability of a trait due to the additive effects of alleles

Question 24

hn^2 =

Answer 24

Va/Vp and robs/rexp

Question 25

realized heritability

Answer 25

the response to selection, hn^2 = R/S, mean of the offspring divided by the mean of the starting population (parents)

Question 26

heterosis

Answer 26

when two different inbred strains are crossed to each other, the offspring are more vigorous than either parent

Question 27

the dominance hypothesis

Answer 27

the effects of the dominant alleles explain the favorable outcome in a heterozygote

Question 28

the overdominance hypothesis

Answer 28

the resulting hybrids are more vigorous because they are heterozygotes for one or more genes that display overdominance