Final - Lecture 2

Question 1

Considering Hardy-weinburd equilibrium, allele and genotype frequencies will remain constant if we have?

Answer 1

• large population
• random mating
• no selection
• no mutation
• no migration

–> order of importance

Question 2

Good things that come from a population that isn’t large enough

Answer 2

• easy to manage/know/follow
• less expensive
• disease risk management
• follow plans more easily
• easier to get desired traits (selection focus)

Question 3

Bad things that come from a population that isn’t large enough

Answer 3

• less variety (small genetic variation)
• disease risk (genetic defect) –> epidemic/bottleneck
  biology - things look good on paper but don’t always work that way
• decrease economy of scale

Question 4

Ugly things that come from a population that isn’t large enough

Answer 4

• harder to avoid inbreeding
• genetic drift = rapid loss of alleles
• G.D. decreases in large populations (N=1000)

Question 5

What does population size define?

Answer 5

Whether or not breeder is going to end up with inbreeding

- as N increases, F decreases

Question 6

What are the first things to be affected by inbreeding?

Answer 6

Reproduction and fertility (fitness)

- have low heritability

Question 7

Another term for inbreeding?

Answer 7

Line-breeding

Question 8

When is inbreeding typically not a problem?

Answer 8

Open population (Ne)

Question 9

What does inbreeding lead to?

Answer 9

Increased homozygosity and decreased heterozygosity

- reduced genetic diversity = reduced genetic variation

Question 10

Example of regionalized dog breeds

Answer 10

German shepherd, norfolk terrier, Boston terrier

Question 11

Genetic drift

Answer 11

over a number of generations with a closed population, allele frequencies either increase/decrease
- allele can be fixed

Question 12

Scenario: 8 unrelated females and 1 unrelated male

1. problems
2. strategies
3. solutions
4. process

Answer 12

1. Ne = 4 - don’t have many individuals contributing to variation; all half sibs (inbreeding); 1 male (does he work?)
2. import more males; adjust mating scheme; breeding guarantee
3. keep track of pedigrees; segregate; ID
4. research biology (report, life cycle, maturity, litter size, maternal danger, market research

Question 13

Inbreeding assumptions

Answer 13

• closed population
• random mating
• discrete generations
• constant N/Ne

Question 14

Population size rule of thumb

- minimum viable population

Answer 14

Ne > 12 = to avoid deleterious mutation
Ne > 50 = avoid inbreeding depression
Ne > 500 = for sufficient genetic variability

Question 15

Population size assumptions

Answer 15

• constant population size across generations
• constant proportion of males/females
• closed population
• random mating
• equal progeny from each parent
• discrete generations