Outbreeding

Question 1

what is outbreeding?

Answer 1

mating between individuals less closely related than the average of the population

Question 2

what are the 4 kinds of outbreeding?

Answer 2

1. Within breed
2. grading up
3. crossbreeding
4. species crosses

Question 3

describe outbreeding within breeds

Answer 3

crossing inbred lines, intense selection for economically important traits within each line

Question 4

describe grading up outbreeding

Answer 4

also called topcrossing, mating purebred males (superior) to non-purebred females (grade) to create a purebred population

Question 5

describe cross breeding

Answer 5

crossing different breeds

Question 6

describe species crosses

Answer 6

between closely related species, some good some bad

Question 7

what are the effects of outbreeding?

Answer 7

the opposite of inbreeding, so increase in heterozygosity, keeping deleterious genes in recessive form, phenotypic: heterosis or hybrid vigor, favorable GCV

Question 8

what is heterosis?

Answer 8

the difference or superiority between crossbred and purebred offspring from the population

Question 9

discuss outbreeding, specifically crossbreeding, in meat animal production

Answer 9

used by most commercial producers, but often crossbreds will not exceed purebred parents for individual traits, but heterosis for all traits will cumulate and result in greater net economic merit than the best average straightbred

Question 10

what is breed complementation?

Answer 10

combining the desirable characteristics (traits) of 2 or more breeds (lines) into the same offspring

Question 11

in outbreeding, the degree of heterosis and complimentarity depends on what 2 things?

Answer 11

1. genetic relationship of the parents

2. the trait, heritability and the ability to measure that trait