Ch 13

Question 1

component of the genetic variance in a character that is attribute to additive effects of alleles

Answer 1

additive genetic variance

Question 2

evolution of internal factors during development that reduces the effect of perturbing environmental and genetic influences, thereby constraining variation and consistently producing a particular

Answer 2

canalization

Question 3

natural selection fro specific combinations of traits, such that selection on one trait is correlated with selection on the other

Answer 3

correlated selection

Question 4

genetic correlation, together with character correlation caused by different environmental conditions

Answer 4

environmental correlation

Question 5

variation among individuals in a phenotypic trait that is caused by variation in the environment rather than by genetic differences

Answer 5

environmental variance

Question 6

effect of the interaction between two or more gene loci on the phenotype or fitness whereby their joint effect differs from the sum of the loci taken seperately

Answer 6

epistasis

Question 7

process whereby a phenotype whose development is triggered by an environmental stimulus evolves to be constitutively expressed

Answer 7

genetic assimilation

Question 8

correlated differences among genotypes in two or more phenotypic characters, due to pleiotrophy or linkage disequilibrium

Answer 8

genetic correlation

Question 9

variance in a trait within a population, as measured by the variance that is due to genetic differences among individual

Answer 9

genetic variance

Question 10

phenotypic variation arising from the difference in the effect of the environment on the expression of different genotype

Answer 10

genotype x environment interaction

Question 11

proportion of the variance in a trait among individuals that is attributable to difference in genotype (narrow sense is the ratio of additive genetic variance to phenotypic variance)

Answer 11

heritability

Question 12

set of phenotypic expression of a genotype under different environmental conditions

Answer 12

norm of reaction

Question 13

accounts for the correlation that may be observed between phenotypic character within a population

Answer 13

phenotypic correlation

Question 14

Correlation between the state of two or more functionally related characteristics, so that they are advantageously matched in most individuals

Answer 14

phenotypic integration

Question 15

capacity of an organism to develop any of several phenotypic states, depending on the environment; usually this capacity is assumed to be adaptive

Answer 15

phenotypic plasticity

Question 16

variance in a trait within a population; it may include both genetic variance and environmental variance

Answer 16

phenotypic variance

Question 17

chromosome region containing at least one gene that contribution to variation in a quantitative trait

Answer 17

QTL mapping

Question 18

genetic analysis of continuously varrying characters, often employing statistical descriptions and estimators of variation

Answer 18

Quantitative genetics

Question 19

heritability of a trait as calculated retrospectively from the change in a population’s mean phenotype, relative to the selection differential that was applied to the character in an artificial selection experiment

Answer 19

realized heritability

Question 20

change in the mean value of a character over one or more generations due to selection

Answer 20

response to selection

Question 21

difference between the mean character value in a population before selection, and in the subset of individuals that survive and reproduce

Answer 21

selection differential

Question 22

slope of the relationship between phenotype and fitness, for a quantitative character, usually taking correlations with other characters into account

Answer 22

selection gradient

Question 23

mean character value at which a population ceases to respond to continuing directional selection

Answer 23

selection plateau

Question 24

characteristic that is expressed as discrete states, although the genetic variation underlying it is polygenic

Answer 24

threshold trait

Question 25

capacity for survival; often refers to the fraction of individuals surviving to a given age, and is contrasted with inviability due to deleterious genes

Answer 25

variability