Genetics of Animal Breeding

Additive genes

Genes that control most livestock traits

Nonadditive genes

Genes controlled by only one of few pairs of genes

Chromosomes

Hereditary materials contained in the nucleus

23

Humans have _ pairs of chromosomes

30

Cattle have _ pairs of chromosomes

30

Goats have _ pairs of chromosomes

Mitosis

The division that increases the amount of body cells that leads to growth

Meiosis I

The division that reduces chromosomes by one-half

Meiosis II

The division that is equational; keeps the chromosome number the same but seperates duplicated sister chromatids

Fertilization

When male sperm reaches the female egg

Genes

Provide the code for protein and enzyme synthesis

Semiconservative

DNA is duplicated by ____ replication

Sex-limited

Genes only expressed in one sex

Sex-influenced

Genes dominant in one sex, but recessive in the other

Male

Sex in mammals are determined by the ___ parent

Female

Sex in poultry are determined by the ___ parent

Parturition

Act of giving birth

Estrus

Period of time in which a female will accept males for breeding

Ovulation

The release of the egg from the ovary

Gestation

Period of time when an animal is pregnant

Colostrum

Type of milk produced directly after birth

Conservative replication

Replication keeps the original parental DNA double helix completely intact while generating an entirely new, separate daughter molecule

Dispersive replication

Replication that breaks the parental DNA into segments, resulting in daughter molecules with alternating new and old strands

Semiconservative replication

Replication that separates the two parental strands so that each individual strand can serve as a template, resulting in two DNA molecules that each contain one old and one new strand

Six basic crosses (types of genetic combination)

Monohybrid cross, dihybrid cross, testcross, backcross, reciprocal cross, trihybrid cross

4-7° below body temperature

Spermatogenesis occurs at what temperature?