Flashcards
Population Differentiation and Phylogeography
Cards in this deck (21)
- 1Endosymbionts Erigone atra 2More likely to ballon if not infected with Richettsia
Longlivety/reproductive success not effected - 2Population Differentiation and Gene Flow 2Individuals of species may be subdivided - spatially distinct populations that differ
Mating random in each pop but not between - 3Panmicitc 2No subdivision inpopulation
population that can freely mix and breed with another to make hybrids
Very rare - 4Linyphilid Spiders 2Endosymbionts - spiders infected with maternally inherited intracellular bacteria
Alter bacteria of host to favour own transmission - 5Models of Genetic Exchange Between Populations 3Mediated by movement of individuals
Nat. sel. and random genetic drift = contribution the migrating individual makes to gene pool - 6Models of Genetic Exchange Between Populations Assumptions 5UNTRUTHFUL
All populations are created equal, with N individuals and equal contributions to migrant pool
All populations equally close to other populations
No selection or mutation
Have to assume equally successful movement/breeding/finding of resources - 7Metapopulation Structure 3Series of subdivided populations
Connected by different migration rates
Physical barriers may affect migration also - 8Endosymbionts Acraea Butterflies 3Riokettsia bacteria
Kills off males off
= lack of males
= females lekking as reserved competition - 9Selective Sweeps 5Loci not always inherited independly
Co-inherited traits/genes 'swept' to high frequency with ones under selection
= reduced genetic diversity
Can be caused by maternally acquired endosymbionts
Bacteria promotes own transmission by increasing of infected females
1st females alleles swept to high frequency - 10Endosymbionts Tetranychus Spider Mites 3Wolabachia infect females
Aggregate offspring
Promote sibling mating - 11Endosymbionts Gryllus Crickets 2Closely related species, normally reproductivelly isoloated from each other
Curing of Wolbachia infection
= viable hybrids - 12Population Structure and Heterozygosity 6Individual population may/may not in Hardy-Weinberg equilibrium
Structured population - overall number of heterozygotes can be fewer than expected
Population structure unknown - Difficult to distinguish between TRUE heterozygotic deficiency and APPARENT heterozygotic deficiency
Use markers to tell level of population subdivision - 13Metapopulation Structure and Gene Flow 3Amount of genetic exchange on strength of selection
No selection = migration very strong force for equalising gene frequency between populations
Selection = genetic differentiation maintained despite migration - 14Patterns From the Past 5Geographical distribution reflect primarily colonisation history
3 migration routes through Europe following last glaciation = hybrid zones
Grasshoppers up mountain sounds different to below
Couldn't outcompete each other = sound diff. to mate
Overlap/hybrid zones for Ensatina species complx (salamanders) - 15Effective Population Size 1Determined by number of individuals contributing to next generation
- 16Factors that Influence Population Size Including Fluctuations 4Effective population size (Ne) closer to small mean population size
Never re-coup what previously lost
Lowest number used = disproportionate effect
Eh Soay sheep population change in size in cyclical manner - 17Effective Population Size (Ne) Unequal Sex Ratios 3Sex biased population
= More closely related generations
= Less genetic types - 18Effective Population Size (Ne) Unequal sex ratios Example 6Eg Racer Spider - Pityohphantes phyrygianus
Female biased population
Manipulating bacterium?
Females genetically determine sex ratio?
Sperm has more X chormosomes?
Adapt particular position to determine sex of offspring? - 19Endosymbionts Tribolum confusum (Flour Beetles) 2Uninfected females produce no offspring if mating with an infected male
Infect male more fertile than uninfected male - 20Ne Variation in Reproductive Success Between Individuals 2Influences sexually dimorphic population sizes
Eg Seals and the beachmasters - 21Ne Population Subdivision 2Separate Ne for each of the populations
Ne influenced by migration rates between populations and chance of extinction for any particular population
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- Degree Evolutionary Biology of Animals Flashcards on Population Differentiation and Phylogeography, created by katy.lynock on 22/05/2013.
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