first 1/2 of exam 2

Question 1

Quantitative genetics

Answer 1

The branch of genetics dealing with the genetic model for quantitative traits and its applications.

Question 2

Qualitative trait

Answer 2

traits in which phenotypes are expressed in categories

Question 3

Quantitative trait

Answer 3

traits in which phenotypes show continuous (numerical) expression

Question 4

polygenic trait

Answer 4

A trait affected by many genes, no single gene having overriding influence.

Question 5

Basic model for quantitative traits

Answer 5

used with polygenetic traits in which phenotypes show numerical expression, p=u+G+E

Question 6

Genotype value

Answer 6

effect of teh individuals genes (singly and in combination) on its performance for the trait

Question 7

Additive gene effects

Answer 7

most important type of gene action controlling quantitative traits

Question 8

non additive gene effects

Answer 8

gene combination effects

Question 9

Dominance

Answer 9

interaction between alleles at a single locus

Question 10

epistasis

Answer 10

expression of genes at different loci

Question 11

environmental effect

Answer 11

the effect that external (nongenetic) factors have on animal performance

Question 12

temporary environmental effect

Answer 12

an environmental effect that influences a single performances record of an individual but does not permanently effect the individuals performance potential for a repeated trait.

Question 13

permanent environmental effect

Answer 13

an environmental effect that permanently influences an individuals performance for a repeated trait.

Question 14

breeding value

Answer 14

refers to the value of an individual as a (genetic) parent, breeding effects that are consistently transmitted from parents to progeny, additive genetic worth of an animal relative to some base population; the worth of an individual as a genetic parent

Question 15

Estimated breeding value

Answer 15

a prediction of breeding value

Question 16

progeny difference

Answer 16

half an individuals breeding value - the expected difference between the mean performance of the individuals progeny and the mean performance of all progeny.

Question 17

expected progeny difference

Answer 17

is a prediction of a progeny difference (EPD)

Question 18

independent gene effects

Answer 18

the effect of a gene independent of the effect of the other gene at the same locus (dominance) and the effects of genes at the other loci

Question 19

additive properties of breeding values

Answer 19

sum of independent effects of genes influencing trait

Question 20

Gene combination values

Answer 20

(GVC) part of an individual’s genotypic value that is due to the effects of gene combinations (dominance and epistasis) and cannot, therefore, be transmitted from parent to offspring .

Question 21

the new model

Answer 21

P=u+BV+GCV+E

Question 22

repeated traits

Answer 22

traits for which individuals commonly have more than one performance record

Question 23

producing ability

Answer 23

performance potential of an individual for a repeated trait

Question 24

varaible

Answer 24

any quantity that can take on different numerical values. all elements except u are variables