Heritability

Question 1

What is quantitative genetics?

Answer 1

can be impacted by a multitude of genes, ex. height, milk production, jumping ability, racing ability (genes effecting organs, muscle, behavior, etc)

Question 2

Which of the following traits is a result of quantitative genetics? skin color, Tobiano spotting, dun coloration, appaloosa spotting

Answer 2

skin color

Question 3

What is the Infinitesimal model of genetics?

Answer 3

lots of small genes, each with roughly equal effect

Question 4

Why does the environment need to be standardized when studying genetic effects?

Answer 4

genes interact with the environment; indeed, the environment is part of the phenotype.

Question 5

What was one of the impact’s when RA Fisher’s Infinitesimal theory was applied?

Answer 5

dairy producers saw a logarithmic increase in milk production per cow

Question 6

What is the difference between the population average and the average variation in the population for a trait?

Answer 6

the variation is the range around the average

Question 7

What is an example of something that is genetic and has a heritability of 0.0?

Answer 7

number of legs

Question 8

What is an example of something that has a heritability of 0?

Answer 8

clipped mane of horse

Question 9

What is a trait that is the result of additive genetics?

Answer 9

height

Question 10

Why do heritability studies focus on additive. modes of inheritance rather than recessive/dominant and epistasis?

Answer 10

dominant/recessive genetics and epistasis requires a specific set of genes be inherited together and that is less predictive than genes with additive modes of inheritance

Question 11

What is the difference between heritability and estimated breeding value (EBV)?

Answer 11

heritability is characteristic of the trait and estimated breeding value is characteristic of the individual

Question 12

Will heritability of a trait be the same in different breeds?

Answer 12

no, different breeds have different combinations of genes

Question 13

Heritability is standard characteristic of the trait in all members of a species.

Answer 13

false, characteristic of the breed… depends on the genetic constitution of the breed

Question 14

Why might heritability for a trait decrease over time?

Answer 14

improvement of the breed through selection

Question 15

Why might estimated breeding value decrease over time?

Answer 15

improvement of the breed or discovery that offspring are performing lower/worse than predicted

Question 16

What does heritability mean?

Answer 16

the amount of genetic variation for a trait in a population and represented as h^2

Question 17

What does heritability measure?

Answer 17

additive genetics

Question 18

What is additive genetics?

Answer 18

phenotype is sum of large number of genes, each with small effect (all genes showing partial or incomplete dominance)