Population Structure And Nonrandom Mating (Lecture 12) Flashcards
Polyandry
Many males; queen doing mating with males
Polygyny
Many females; lions
Unequal mating success (cooperative breeding)
Acorn woodpecker, grown babies stay with family; work as a group to collect acorns; forgo reproducing for the good of the family
Unequal fecundity
Not all offspring will survive
Consequences beyond sexual selection
Effective number of individual in a population is less than total number of population
Formula for Effective Population Size
Ne= (4Nm*Nf)/(Nm+Nf)
Nonrandom Mating is NOT
Sexual selection but assortative mating (sorting by genotype)
selfing
Mating with themselves
Assortative mating
The probability of an individual mating is determined by BOTH the genotype of the individual and the genotype of the potential mate
F is the
Inbreeding coefficient; ranges from 0-0.5 in 1 generation (identity by descent)
What are we looking at when measuring the inbreeding coefficient?
Want the same exact same copy of a specific allele from the mother to the child (like following a kernel on its journey) (HAS to come from the mother)
Inbreeding does NOT cause
Allele frequency changes, only genotype frequency changes
Heterozygosity is related to F because
Inbreeding reduces the number of heterozygotes
When there is inbreeding Hf=
H0(1-F)
Genetic drift mimics the effects of
Long-Term inbreeding because it increases the probability of identity by descent (random mating includes sometimes between relatives)
Inbreeding increases
Effects of drift; and decrease the effective population size
3 ways to reduce Ne
Mating system, population subdivisions, inbreeding
Inbreeding depression causes
Deleterious recessives to be exposed more frequently in homozygotes, typically lowers mean fitness
What are ways to avoid inbreeding depression
Mate choice, dispersal; even sex biased, selfing compatibility, dioecy, monoecy, asychrony
Mate choice
Can choose to not mate with realtives
Dispersal, even sex biased
Typically males leave to mate with unrelated females
self-incompatibility
Will not ovulate with itself (molecular level); seen in hermaphrodites
dioecy
Separate plants; sexes on different organisms
monoecy
Separate flowers, sexes are on the same organisms but physically separated
Advantages to selfing
Assured reproduction
Assured reproductoin
Need this if partners are scarce or far away
