Fundamentals of Genetics and Breeding in Animal Production

Question 1

Biology of heredity and variation. Deals mainly with the way in which traits of the parents are passed on or transmitted to their offspring

Answer 1

Genetics

Question 2

Branch of genetics concerned with the proper selection and use of the traits of the parent to produce
offspring with predictable and desirable traits for the improvement of animals in general

Answer 2

Breeding

Question 3

Animal traits or characters could be:

Answer 3

1. Morphological (e.g. size, coat, color)
2. Productive performance (e.g. egg and meat production)
3. Behavioral
4. Any visible and measurable innate description

Question 4

Chemical composition: consist of Deoxyribonucleic acid (DNA)- genetic material for all living organism

Answer 4

Gene

Question 5

❖ Due to segregation and assortment of genes, the combined alleles in a locus as well as the combination/interaction of all genes present can result in new individuals or traits differing from the parent.

❖ Traits are influenced by one more gene pairs

Answer 5

Gene interaction/gene expression/gene effect

Question 6

Types of Gene Interactions/Gene Effects/Phenotypic Expression of Genes

Answer 6

A. Non-additive or qualitative
B. Addictive Genes Effects
C. Epistatic Interaction
D. Inheritance of Sex and Sex-Linkage

Question 7

Resultant phenotypic expressions are distinct traits or characters (discontinuous variations)

Answer 7

A. Non- additive or qualitative

Question 8

one allele masks the effect/action of the other locus

Answer 8

Complete Dominance

Question 9

(also called no dominance or lack of dominance)
Neither allele in a locus is dominant, the heterozygous offspring
intermediate or blende phenotype

Answer 9

Incomplete or partial dominance

Question 10

heterozygous individuals are superior (possess greater vigor or are more desirable) to
either heterozygotes, and are said to possess heterosis or hybrid vigor

Answer 10

Overdominance

Question 11

two (both) alleles of a single locus are responsible for the production of two phenotypically
distinct and detectable gene products.

Answer 11

Codominance

Question 12

Involves several pairs of genes affecting production traits

Answer 12

Addictive Genes Effects

Question 13

A gene or pair which affect the expression of genes in other loci or chromosomes, not allelic
(epistasis- masking of the phenotype effect either or both members of one pair of alleles of
different pair. The masked gene is called hypostatic)

Answer 13

Epistatic Interaction

Question 14

pair of chromosomes that determines the sex of zygote

Answer 14

Sex chromosomes

Question 15

traits found on the sex chromosomes

Answer 15

Sex – Listed Traits

Question 16

Generic make-up of the trait represented by the genes carried on the chromosomes

Answer 16

Genotype

Question 17

Visible or measurable character representing the genotype

Answer 17

Phenotype

Question 18

group of animals descended from common ancestry and possessing certain inherited traits that distinguish it from any other group

Answer 18

Breed

Question 19

group of animals descended from appraised to a specific animal or source of genetic stock

Answer 19

Line

Question 20

group of animals within a breed with traits that distinguish them from others in the breed

Answer 20

Strain

Question 21

mixed or unknown breed, “scrub”, little improved breeding animal

Answer 21

Mongrel

Question 22

a record of ancestor

Answer 22

Pedigree

Question 23

to remove from a herd or flock, usually because of age, low performance, or undesirable traits

Answer 23

Cull

Question 24

tendency of a breeding animal to have a long productive life

Answer 24

Longevity

Question 25

functional unit of inheritance; a small segment of chromosome (DNA) that is specific code for a particular trait and determines how it will develop

Answer 25

Gene

Question 26

an expression of a gene/portion of the DNA through the effects of enzyme/protein as dictated by the genetic information or the genes

Answer 26

Trait

Question 27

a rod-like or string like body occurring in pairs, found

Answer 27

Chromosome

Question 28

study of chromosomes

Answer 28

Cytogenetics

Question 29

Presentation of the chromosomes of any individual/species, usually cut-out prints, matched up and arranged in a standard sequence or order

Answer 29

Karyotype

Question 30

pertaining to similar or corresponding structure within a biological system

Answer 30

Homologous

Question 31

A process in which a cell divides to produce two daughter cells, each of which contains the same chromosomes complement (2N) as the cell from which they came

Answer 31

Mitosis

Question 32

Special type of cell nuclear division for the production of gametes (Sperm and ovum). As a result, each gamete carries half the number of chromosomes (n) of a typical body of that species.

Answer 32

Meiosis

Question 33

having the normal, paired chromosomes of somatic tissues as produced by the doubling of the primary chromosomes of the germ at fertilization

Answer 33

Diploid

Question 34

having exactly one-half of the usual Diploid number of chromosomes for a given species (gametes are said to be *******)

Answer 34

Haploid

Question 35

process by which sperm (spermatogenesis) and eggs (oogenesis) are produced

Answer 35

Gametogenesis

Question 36

genes occupying corresponding loci in homologous chromosomes that affect the same hereditary trait but in different ways

Answer 36

Alleles

Question 37

location of a gene in a chromosome

Answer 37

Locus

Question 38

One of the gene/alleles at corresponding loci in homologous chromosomes, which overpowers or dominate the expression of the other alleles

Answer 38

Dominant Allele

Question 39

whose expression is prevented/over powered by the dominant alleles

Answer 39

Recessive allele

Question 40

having genes, located at corresponding loci in homologous chromosomes which correspond (similar) to each other in the way they control on traits

Answer 40

Homozygous

Question 41

having contrasting genes/alleles

Answer 41

Heterozygous

Question 42

performance of offspring that is greater than the average of the parents. Usually the amount of superiority of the crossbreed over the average of the parental breed. Also referred to as hybrid vigor

Answer 42

Heterosis

Question 43

Purebred livestock are typically from the purebreds for which their ancestry is recorded as a pedigree by a breed association

Answer 43

Purebred breeders (seedstock producers)

Question 44

Commercial slaughter/market livestock are crossbred resulting from crossing two or more traits or lines of breeding

Answer 44

Commercial breeders (producers)

Question 45

Methods of Breeding:

Answer 45

1. Artificial Breeding 2. Natural Breeding

Question 46

In combination with selection are utilized in most herd/flocks to optimize improvement. Based primarily on the genetic relationship of animal being mated

Answer 46

Mating Systems (Breeding System)

Question 47

Two Major System of Mating:

Answer 47

1. Inbreeding 2. Outbreeding (Outcrossing)

Question 48

Types of inbreeding:

Answer 48

1. Intensive inbreeding (close breeding) 2. Linebreeding

Question 49

Mating of closely related animals whose ancestors had been inbred for several generations Examples: brother x sister

Answer 49

Intensive inbreeding (close breeding)

Question 50

A mild form of inbreeding where inbreeding is kept relatively low while maintaining a high relationship to an outstanding ancestor (usually a sire) or line of ancestor Example: Grandson x Granddaughter

Answer 50

Linebreeding

Question 51

Types of Outbreeding:

Answer 51

1. Species cross 2. Crossbreeding 3. Grading up 4. Line or strains cross 5. Random mating 6. Purebreeding

Question 52

mating of the female offspring to one of the parental breeds

Answer 52

Back Crossing

Question 53

Special Crossbreeding Program:

Answer 53

1.) 2-Breed (Way) Rotational Cross 2.) 3 Breed Cross Rotational Cross (Triple Crossing) 3.) Back Crossing 4.) Rotaterminal Cross System