Breeding and Genetics

Question 1

generation of gametes for sexual reproduction through meiotic division

Answer 1

gametogenesis

Question 2

containing only one set of chromosomes, gametes are these

Answer 2

haploid cell

Question 3

When two gametes (haploid cells) fuse together

Answer 3

Diploid

Question 4

Animals inherit one set from father and one set from mother

Answer 4

chromosomes

Question 5

heterozygous

Answer 5

Qq (having different alleles on chromosomes)

Question 6

homozygous

Answer 6

QQ, qq (having the same alleles on parental chromosomes)

Question 7

controlled by one, or very few genes and are much easier to predict

Answer 7

qualitative traits (simply inherited traits)

Question 8

controlled by many loci

Answer 8

polygenic traits

Question 9

a continuum stating herd distribution and likelihood of a trait

Answer 9

Normal (Bell) Curve

Question 10

the shape of the normal curve is determined by a measure of the amount of variation in the population

Answer 10

phenotypic standard deviation

Question 11

phenotypic mean (herd average) is located at the very center of the

Answer 11

x-axis

Question 12

frequency of the phenotype occurs on the

Answer 12

y-axis

Question 13

the way alleles interact with each other (dominance, recessive)

Answer 13

gene action

Question 14

dominant allele completely masks the effects of the recessive allele; in this case the phenotype is identical to that of the dominant

Answer 14

complete dominance

Question 15

the phenotype of the offspring is somewhere in the middle, more closely resembling the dominant

Answer 15

partial dominance

Question 16

phenotype of the heterozygote is outside the range of possible phenotypes exhibited by the two parents (more closely related to dominant allele)

Answer 16

over-dominance

Question 17

no dominance whatsoever

Answer 17

co-dominance gene action

Question 18

phenotype is exactly intermediate to the two homozygotes (no dominant allele)

Answer 18

additive gene action

Question 19

chromosomes that determine the sex of the individual

Answer 19

allosomes

Question 20

pattern of inheritance for sex-related (female/male) genes is referred to as

Answer 20

sex-linked inheritance

Question 21

traits in which phenotypic expression is limited to one sex

Answer 21

sex-limited traits

Question 22

phenotypic expression differs among males and females even if the genotype is the same

Answer 22

sex-influenced traits

Question 23

different loci are also interacting with each other

Answer 23

epistasis

Question 24

population average (u) + genetic effects (G) + environmental effects (E) =

Answer 24

Phenotype (P)

Question 25

a measure that indicates what proportion of the observed phenotypes is due to genetics

Answer 25

heritability

Question 26

growth and stature rates (average daily gain and body weight)

Answer 26

traits with high heritability

Question 27

EBV

Answer 27

expected breeding value

Question 28

EPD

Answer 28

expected progeny differential

Question 29

ETA

Answer 29

estimated transmitting ability

Question 30

descendants or offspring

Answer 30

progeny

Question 31

a measure that tells producers how confident they should be in an EBV or EPD estimate

Answer 31

accuracy value

Question 32

Benefits of moderate inbreeding

Answer 32

Breeding related animals could help to fix favorable alleles within a population, and increase uniformity within a herd.

Question 33

overuse of inbreeding resulting in detrimental consequences

Answer 33

inbreeding depression

Question 34

improved performance of progeny compared to parents

Answer 34

heterosis

Question 35

this system has been developed to maximize the amount of heterosis achieved by each generation

Answer 35

crossbreeding

Question 36

sires selected for terminal traits, while females are selected for maternal traits (marketed offspring)

Answer 36

terminal cross

Question 37

pure sires are rotated each generation and mated to crossbred females that are least like their own breed composition (rotate sires)

Answer 37

rotational cross

Question 38

maternal rotation to produce replacement females with a terminal cross to take full advantage of hybrid vigor (A, B females and A, B, C breeds)

Answer 38

rota-terminal crossbreeding system