ch. 20 (quantitative genetics and multifactorial traits)

Question 1

Genetic variance attributed to the substitution of one allele for another at a given locus. This variance can be used to predict the rate of response to phenotypic selection in quantitative traits.

Answer 1

additive variance (VA)

Question 2

The contribution of the genotypic variance responsible for the phenotypic variation of a trait observed in a population.

Answer 2

broad-sense heritability (H2)

Question 3

A quantitative trait whose phenotypic variation is the result of the interaction of additive alleles from multiple genes and environmental factors. Also called a multifactorial trait.

Answer 3

complex trait

Question 4

Condition when identical twins both express a trait or neither of them express that trait.

Answer 4

concordance

Question 5

In quantitative genetic studies, a statistical value describing the degree of association between two interrelated traits.

Answer 5

correlation coefficient (r)

Question 6

In quantitative genetic studies, a statistical value describing how much observed variation is common to two interrelated traits.

Answer 6

covariance (covXY)

Question 7

Condition when one member of a set of identical twins expresses a trait, while the other member does not

Answer 7

discordance

Question 8

Twins produced from separate fertilization events; two ova fertilized independently.

Answer 8

fraternal twins (DZ twins)

Question 9

For a given trait, a measure of the proportion of total phenotypic variation in a population that is due to genetic factors.

Answer 9

heritability

Question 10

Twins produced from a single fertilization event; the first division of the zygote produces two cells, each of which develops into an embryo.

Answer 10

identical twins (MZ twins)

Question 11

In statistics, the arithmetic average.

Answer 11

mean

Question 12

Proposal describing the inheritance of a phenotypic character controlled by many genes, each behaving in a Mendelian fashion and contributing to the phenotype in a cumulative or quantitative way.

Answer 12

multiple-factor hypothesis

Question 13

The proportion of phenotypic variance in a population due to additive genotypic variance.

Answer 13

narrow-sense heritability

Question 14

F2 populations from crosses of inbred strains that carry different parts of the P1 parental genomes and associated QTL genotypes and phenotypes.

Answer 14

QTL mapping population

Question 15

Two or more genes that act on a single polygenic trait in a quantitative way.

Answer 15

quantitative trait loci (QTLs)

Question 16

A quantitative measure of the amount of variation present in a sample of measurements from a population calculated as the square root of the variance.

Answer 16

standard deviation (s)

Question 17

A quantitative measure of the amount of variation present in a sample of measurements from a population calculated as the square root of the variance.

Answer 17

standard deviation (s)

Question 18

Statistical calculation that compares variation between the means of multiple samples in a population.

Answer 18

standard error of the mean (S)

Question 19

A statistical measure of the variation of values from a central value, calculated as the square of the standard deviation.

Answer 19

variance (s2)