Chapter 2- Animal Breeding And Genetics Flashcards Preview

Agriculture Science 100 > Chapter 2- Animal Breeding And Genetics > Flashcards

Flashcards in Chapter 2- Animal Breeding And Genetics Deck (35)
Loading flashcards...
0

What is the difference between animal breeding and animal propagation

-animal breeding is increasing the quality of each generation
-animal propagation is increasing animal numbers

1

What is the genotype

Genetic makeup of an animal

2

What is the phenotype

The animal's actual performance

3

What influences the phenotype

Depends on the genetic makeup and the effects of temperature, feed, stress, and management

4

What are cells composed of

-outer membrane, inner cytoplasm, and nucleus

5

What does the nucleus contain

-heredity material of the cell
-controls the cell's growth, metabolism, and reproduction

6

Where is the genetic material found

Chromosomes

7

What determines the animal's genotype and what are they

Genes are composed of DNA and each animal has a slightly different combination

8

What is necessary to determine a given trait and where are they located

A pair of genes is needed to determine a given trait and they are located on the same site on homologous chromosomes

9

What is a gene

Heredity unit consisting of a DNA sequence at a specific location on a chromosome

10

What is an allele

A gene found on the same location of homologous chromosomes

11

What is homozygous.

When both genes at a particular location on homologous chromosomes are on the same allele or are identical

12

What is heterozygous.

When two alleles are a given location in homologous chromosomes are not the same

13

What is dominant

A gene whose effect masks the phenotypic expression of its allele, shown by capital letters

14

What is recessive

A gene whose expression is hidden by a dominant gene and only expresses itself when in the homozygous state, shown by lower case letter

15

What qualitative traits have modifying genes that cause minor variations in phenotype

-coat color
-honed versus pulled cattle
-in cattle, at least nine major loci affect
-hair color and hair pattern
- in general, black is dominant

16

What is a mutation

When a trait that did not exist in either parent appears

17

What happens to mutations

-mutated genes are passed to the offspring
-some mutations are beneficial, harmful, or little significance

18

What are common causes of mutations

-Exposure to various chemicals
-exposure to radiation

19

What are the four systems mating

-inbreeding
-line breeding
-outcrossing
-cross breeding

20

What is inbreeding.

Mating of animals that are more closely related to each other than the average relationship in a population

21

What does inbreeding cause

-A decrease in performance in traits such a fertility, survivability, and hybrid vigor called inbreeding depression
-the undesirable genes tend to become more homozygous

22

How can inbreeding be useful

-With heavy culling it increases homozygosity for the superior genes

23

What happens with intensive inbreeding

D1- gets 50% of genes
D2- gets 75% of genes
D3- gets 87.5% of genes
D4- gets 93.75% of genes

24

What is line breeding

-Mating if several generations of offspring to a particular animal or it's descendants
-common ancestor is not as closely related as inbreeding

25

What is the benefit of line breeding

Concentrate the superior genes of a particular family or animal

26

What is outcrossing.

Mating of animals with no common ancestors on the immediate pedigree within a breed

27

What is the benefit of outbreeding

It increases heterozygosity and thus, usually, hybrid vigor

28

What is continuous outbreeding

The yearly mating of females in a population to unrelated males

29

What is cross breeding

-The mating of the sires of one breed to the dams of another breed
-heterosis lasts only one generation