G18

Question 1

what is the inbreeding coefficient

Answer 1

F= HE-HO/HE

Question 2

what are the two major genetic consequences of inbreeding

Answer 2

1. alters genotype frequency NOT ALLELE FREQUENCY

2. Reduced effective recombination

Question 3

what happens to heterozygosity in selfing plants

Answer 3

decreases
heteros mate with self = 50% hetero , 50 homo
homos mate = 100% homo

Question 4

what is an allozygous homozygote

Answer 4

homozygous but both alleles come from a different individual

Question 5

what is an autozygous homozygote

Answer 5

both alleles are identical by descent

Question 6

what is the probability of autozygosity

Answer 6

F=(1/2)^i(1+FA)
A = common ancestor
i = number of individuals in path

Question 7

what are the benefits of inbreeding

Answer 7

reproductive assurance

increased gene transmission

Question 8

give an example of reproductive assurance

Answer 8

e.g haplodiploidy insects: solitary females can produce sons to mate with and produce diploid daughter

Question 9

give an example of increased gene transmission

Answer 9

self compatible plants have 50% adv if cost of producing selfing pollen dfoesnt affect quantity of outbreeding pollen

Question 10

how can inbreeding be increased

Answer 10

by structural changes (eg. in plants)

due to offspring mating/dispersal patterns

Question 11

give an example of strucutral changes which increase inbreeding

Answer 11

reduction of sexual adaptations eg.g cleistogamous flowers produce buds that dont open

Question 12

give an example of increased inbreeding due to offspring mating/dispersal patterns

Answer 12

Sex ratio bias and haplodiploidy in parasitc hymenoptera and mites, females should produce 1:1 sex ratio in offspring, but not if offspring hatch adn mate before dispersing.
extreme example: mite acarophenax 1 son to 15 daughters

Question 13

what is inbreeding depression

Answer 13

relative decrease in fitness of inbred progeny compared to non inbred progeny (cumulative)

Question 14

give ane example of inbreeding depression

Answer 14

nestling mortality rate in inbred pairs of great tits

Question 15

what are the two hypothesis for the causes of inbreeding depression

Answer 15

1. overdominance hypothesis: genome wide heterozygosity is advantageous and this is reduced by inbreeding
2. dominance hypothesis: unmasking of deleterious recessives

Question 16

what is purging of deleterious recessives

Answer 16

when invreeding depression leads to an inital decrease in population fitness, but population may recover to some extent if not fully if the deleterious alleles are selected against (purged)

Question 17

give an example of purging deleterious recessives

Answer 17

chillingham cattle
isolated for 300 years
underwent a population crash to 5 bulls and 8 cows
now back to 91 but very homozygous, with no reduction in fertility or viability.
pruging effect is also significant for inbred sumatran tigers in zoos

Question 18

give to examples of plants promoting outbreeding

Answer 18

monecious plants: heterostyl- plants may ahve male and female acting flowers at different times (protogyny and protoandry)
Dioecious plants: sexes on different plants. eg male and female holly

Question 19

what is an example of a molecular adaptation promiting oubreeding

Answer 19

multi alleleic incompatibiltiy systems
eg. plant has S1S2 aleles only pollen with different s allels grow down stigma.
common in plants ciliate, basidommycetes and slime moulds

Question 20

what are some examples of behavioural adaptations promoting outbreeding

Answer 20

kin recognition in social animals
young females dont come into breeding condition if father is dominant eg. black tailed prarie dog
striped mouse: presence of male accelerates juvenile female growth rates but not if caged with father

Question 21

give an example of optimal levels of outbreeding

Answer 21

delphinium flower, found outbreeding increased fittness until 10m distance when it began to decrease with distance.