Part II (Module 1: Definition Of Terms)

Question 1

The cell produced by the union of mature gametes (egg and sperm) in reproduction.

Answer 1

Zygote

Question 2

The allele at a particular SNP that is the least frequent in a population.

Answer 2

Variant Allele

Question 3

A distinct variant of a phenotypic character of an organism that may be inherited,
environmentally determined or a combination of the two.

Answer 3

Trait

Question 4

The X or Y chromosomes.

Answer 4

Sex Chromosomes

Question 5

The linear arrangement of nucleotides that make up unbranched polymer chains
of DNA or RNA.

Answer 5

Sequence

Question 6

Any natural or artificial process favoring the survival and propagation of certain
individuals in a population.

Answer 6

Selection

Question 7

The separation of paired alleles at loci during germ cell formation

Answer 7

Segregation

Question 8

Ribonucleic acid, involved in the transcription of genetic information from DNA.

Answer 8

RNA

Question 9

Applies to one member of an allelic pair which lacks the ability to manifest itself

Answer 9

Recessive

Question 10

A mating system in which animals are assigned as breeding pairs at random,
without regard to genetic relationship or performance.

Answer 10

Random Mating

Question 11

A locus that affects a quantitative trait.

Answer 11

Quantitative Trait Locus

Question 12

A trait that is represented by an almost continuous distribution of
measurements. Examples include average daily gain, backfat thickness, and height.

Answer 12

Quantitative Trait

Question 13

A trait that can generally be classified into a limited number of categories,
and the animal can be said to “possess” the quality or not. Examples include hair color, skin
color, and ear stature.

Answer 13

Qualitative Trait

Question 14

Any of a group of complex nitrogenous organic compounds that contain amino acids as their basic structural units, occur in all living matter, and are essential for the growth and repair of animal tissue.

Answer 14

Protein

Question 15

A test used to help predict an individual’s breeding values, involving multiple
matings of that individual and evaluation of its offspring

Answer 15

Progeny Test

Question 16

Offspring or individuals resulting from specific matings

Answer 16

Progeny

Question 17

The branch of genetics which deals with frequencies of alleles in groups
of individuals.

Answer 17

Population Genetics

Question 18

Entire group of organisms of a kind that interbreed

Answer 18

Population

Question 19

Where DNA or genes have more than two forms or alleles in the population.

Answer 19

Polymorphism

Question 20

Variation in phenotype which results from variation in genetic and
environmental effects on the individuals.

Answer 20

Phenotypic Variation

Question 21

performance record; a measure of an animal’s performance for a trait.

Answer 21

Phenotypic value

Question 22

When two traits tend to change in the same or different direction as
a net result of genetic and environmental effects

Answer 22

Phenotypic correlation

Question 23

Actual exhibit of observable traits. Normally, it refers to physical characteristic of an individual such as size, shape, color, or performance.

Answer 23

Phenotype

Question 24

The set of all phenotypes expressed by a cell, tissue, organ, organism, or species

Answer 24

Phenome

Question 25

Genetically determined characteristic which can be possessed by an organism. A synonym of trait.

Answer 25

Phene

Question 26

Environmental effects that result in permanent effects on the phenotypic expression of a trait. For example, severe mastitis during lactation may have a permanent effect on milk production and litter weaning weight for an animal in subsequent litters.

Answer 26

Permanent Environmental Effects

Question 27

proportion of the individuals with a particular gene combination that express the corresponding trait.

Answer 27

Penetrance

Question 28

Usually refers to pedigree chart or what a pedigree chart represents in genetics. It is a document to record the ancestry of an individual. Also used to illustrate the family structure or breeding scheme.

Answer 28

Pedigree

Question 29

Mating of individuals that are less closely related than the average of the

Answer 29

Outcrossing

Question 30

contribute to individual fitness and to the evolution of animal genetic resources. By definition, these traits are also important to the ability of the animal genetic resource to be sustained in the production environment

Answer 30

Adaptation Traits

Question 31

Any one of a class of organic compounds containing the amino (NH2) group and the carboxyl (COOH) group. They are combined to form proteins.

Answer 31

Amino acids

Question 32

One of a pair, or series of alternative forms of a gene that can occur at a given locus on homologous chromosomes

Answer 32

Allele

Question 33

System for genetic evaluations that estimates breeding values of individual animals (males, females) at the same time. The system uses production data on all known relatives in calculating a genetic evaluation.

Answer 33

Animal model

Question 34

Any individual from which an animal is descended

Answer 34

Ancestor

Question 35

Any chromosome that is not a sex chromosome

Answer 35

Autosome

Question 36

cross produced by mating a first-cross animal back to one of its parent lines or breeds.

Answer 36

Backcross

Question 37

Either a sub-specific group of domestic livestock with definable and identifiable external characteristics that enable it to be separated by visual appraisal from other similarly defined groups within the same species, or a group for which geographical and/or cultural separation from phenotypically similar groups has led to acceptance of its separate identity.

Answer 37

Breed

Question 38

mean genetic value of an individual as a parent. It can be estimated as the average superiority of an individual's progeny relative to all other progeny under conditions of random mating.

Answer 38

Breeding value

Question 39

Spindle-fiber attachment region of a chromosome

Answer 39

Centromere

Question 40

Microscopically observable linear arrangement of DNA in the nucleus of a cell. It carries the genes responsible for the determination and transmission of hereditary characteristics.

Answer 40

Chromosomes

Question 41

mean performance of a line when involved in a cross-breeding system

Answer 41

Combining ability

Question 42

average performance when a breed or line is crossed with two or more other breeds or line

Answer 42

General combining ability

Question 43

the degree to which the performance of a specific cross deviates from the average general combining ability of two lines.

Answer 43

Specific combining ability

Question 44

Alleles, each of which produces an independent effect in heterozygotes

Answer 44

Co-dominant alleles

Question 45

A line that is randomly selected and randomly mated. Usually used in selection experiments to monitor environment effects in order to estimate genetic change in a selected line.

Answer 45

Control line

Question 46

Matings between animals of different breeds or lines

Answer 46

Crossbreeding

Question 47

The protoplasm outside a cell nucleus.

Answer 47

Cytoplasm

Question 48

An individual descended from other individuals

Answer 48

Descendant

Question 49

Applied to one member of an allelic pair of genes, which has the ability to express itself wholly or largely at the exclusion of the expression of the other allele.

Answer 49

Dominant

Question 50

The aggregate of all the external conditions and influences affecting the life and development of the organism.

Answer 50

Environment

Question 51

When the gene at one locus affect the expression of the gene at another locus

Answer 51

Epistasis

Question 52

prediction of a breeding value

Answer 52

Estimated breeding value

Question 53

sequence of DNA that is expressed (transcribed) into RNA , then translated into protein

Answer 53

Exon

Question 54

may be separated by an intron, which is later removed from the RNA transcript via a splicing mechanism.

Answer 54

Adjacent exons

Question 55

Animals resulting from crossing parents from different lines or breeds

Answer 55

F1

Question 56

Animals resulting from matings among F1 parents

Answer 56

F2

Question 57

Animals resulting from matings among F2 parents

Answer 57

F3

Question 58

The mean number of offspring per parent that successfully reproduce

Answer 58

Family size

Question 59

Individuals having the same male and female parents.

Answer 59

Full sibs

Question 60

A sperm or egg cell containing the haploid (1n) number of chromosomes

Answer 60

Gamete

Question 61

functional hereditary unit that occupies a fixed location on a chromosome, has a specific influence on phenotype, and is capable of mutation to various allelic forms.

Answer 61

Gene

Question 62

A gene or DNA sequence having a known location on a chromosome and associated with a particular gene or trait; a gene phenotypically associated with a particular, easily identified trait and used to identify an individual or cell carrying that gene.

Answer 62

Genetic Marker

Question 63

Variation in phenotype which results from variations in genetic composition among individuals.

Answer 63

Genetic variance

Question 64

The complete set of genes and non-coding sequences present in each cell of an organism, or the genes in a complete haploid set of chromosomes of a particular organism.

Answer 64

Genome

Question 65

The discipline in genetics concerned with the study of the genome of an organism. The field includes efforts to determine the entire DNA sequence of organisms and fine-scale genetic mapping. It also studies intragenomic phenomena such as heterosis, epistasis, pleiotropy and other interactions between loci and alleles within the genome.

Answer 65

Genomics

Question 66

The genetic constitution of one or a few gene(s) or locus (loci), or total genetic make-up (genes) of an individual organism

Answer 66

Genotype

Question 67

process of repeated backcrossing to one parental line to produce a population that is nearly purebred.

Answer 67

Grade-up

Question 68

Individuals that share only one common parent

Answer 68

Half-sibs

Question 69

A set of alleles at a closely linked group of loci, so closely linked that the allelic set behaves almost as one allele in terms of inheritance.

Answer 69

Haplotype

Question 70

Degree to which a given trait is controlled by inheritance; proportion of total phenotypic variation that is attributable to genetic variation (in contrast to environmentcaused variation)

Answer 70

Heritability

Question 71

degree to which the performance of a crossbred animal is better or worse than the average performance of the parents

Answer 71

Heterosis

Question 72

An organism with unlike members of any given pair or series of alleles, which consequently produces unlike gametes.

Answer 72

Heterozygote, adj. heterozygous

Question 73

Chromosomes which occur in pairs and are similar in size and shape, one having come from the male and one from the female parent.

Answer 73

Homologous chromosomes

Question 74

organism whose chromosomes carry identical members of a given pair of genes. The gametes are therefore all alike with respect to this locus.

Answer 74

Homozygote, adj. homozygous

Question 75

Matings among related individuals, which results in progeny that have less heterozygosity and hence more homozygous gene pairs than the average of the population.

Answer 75

Inbreeding

Question 76

When animals are culled if they do not meet all of the minimum levels of performance for a set of traits.

Answer 76

Independent culling

Question 77

appearance of the metaphase chromosomes of an individual or species, which shows the comparative size, shape, and morphology of the different chromosomes.

Answer 77

Karyotype

Question 78

gene that results in the death of the animal

Answer 78

Lethal gene

Question 79

Both internal (e.g., genetic merit) and external (e.g., nutrition, disease, exposure) forces that influence the expression of a threshold character (e.g., disease, conception, abnormalities, etc.).

Answer 79

Liability

Question 80

Mating of selected individuals from successive generations to produce animals with a high relationship to one or more selected ancestors. It is a mild form of inbreeding

Answer 80

Line-breeding

Question 81

Association of genes physically located on the same chromosome. A group of linked genes is called a linkage group.

Answer 81

Linkage

Question 82

advantage of the crossbred mother over the average of purebred mothers

Answer 82

Maternal Heterosis

Question 83

Rules which describe how selected breeds and/or individuals will be paired at mating.

Answer 83

Mating system

Question 84

process by which the chromosome number of a reproductive cell becomes reduced to half the diploid (2n) or somatic number and results in the formation of eggs or sperm.

Answer 84

Meiosis

Question 85

Movement of animals, and consequently genes, from one population to another.

Answer 85

Migration

Question 86

Refers to the frequency at which the less common allele occurs in a given population

Answer 86

Minor Allele Frequency

Question 87

Small bodies in the cytoplasm of most plant and animal cells responsible for energy production

Answer 87

Mitochondria

Question 88

Cell division process in which there is first a duplication of chromosomes, followed by migration of chromosomes to the ends of the spindle and a dividing of the cytoplasm, resulting in the formation of two cells with diploid (2n) number of chromosomes.

Answer 88

Mitosis

Question 89

branch of genetic studies that deals with hereditary transmission and variation on the molecular level. It deals with the expression of genes by studying the DNA sequences of chromosomes.

Answer 89

Molecular Genetics

Question 90

Three or more alternative forms of a gene representing the same locus in a given pair of chromosomes

Answer 90

Multiple alleles

Question 91

A sudden change in the genotype of an organism. The term is most often used in reference to point mutations (changes in base sequence within a gene), but can refer to chromosomal changes

Answer 91

Mutation

Question 92

Natural processes favoring reproduction by individuals that are better adapted, and tending to eliminate those less adapted to their environment.

Answer 92

Natural selection

Question 93

Part of a cell containing chromosomes and surrounded by cytoplasm

Answer 93

Nucleus