Genetics

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p.reilly1227
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77615
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Genetics
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2011-04-06 02:25:10
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Genetics test questions
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Genetics test questions
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  1. Def: Polymorphism
    Genetic trait with distinct phenotypes
  2. What is nonrandom mating a deviation from?
    Random mating
  3. What are reasons for non-random mating?
    • Phenotypic resemblemce
    • Genetic relatedness
  4. What are the types of deviatons due to phenotypic resemblances?
    • Positive assortment - tendency for like individuals to mate (ie: similiar heights)
    • Negative assortment - tendency for unlike individuals to mate (ie: dissimiliar heights)
  5. What genes does non-random mating due to phenotypic resemblence affect?
    Only genes that encode these traits
  6. What are the types of deviations due to genetic relatedness?
    • Inbreeding: - preferential mating between related individuals
    • Outbreding/Outcrossing: avoidance of mating with related individuals
  7. What Are types of Assortment?
    • Phenotypic resemblences
    • Genetic relatedness
  8. What are the effects of assortive mating?
    • 1: Positive assortment and inbreeding increase homozygosity
    • 2: Negative assortment and outbreeding increase heterozygosity
    • 3:Genotype frequencies change, but Allele frequencies do not
  9. What are the two causes of inbreeding?
    • Mate choice:
    • Population subdivision:
  10. Define inbred
    An individual whose parents are related
  11. Define autozygosity
    Two alleles that are identical by descent
  12. Define allozygosity
    Two alleles that are not identical by descent
  13. What is the inbreeding coefficient?
    (F): the probability that an individuals alleles are autozygous
  14. What are the 5 effects of inbreeding on an individual?
    • Increases homozygosity across genes
    • Expression of recessive alleles
    • (taboos and organisms that routinely inbreed)
  15. Inbreeding 2 effects at a pop level
    • Increased homozygosity relative to HW equilibrium
    • Genotype frequencies change without changing allele frequencies
  16. Define Mutation
    random change in the genetic material
  17. What are the 2 types of mutation?
    • Gene (point) mutation: produce new alleles
    • Chromosomal mutation: produce new chromosomal arrangments
  18. What is mutations importance in evolution?
    • It is not significant on a generation-to-generation time scale
    • It is the source of all novel genetic variation
  19. "Mu" and "v" are directly proportional to _________.
    Forward and backward mutational frequencies.
  20. What are the 3 types of mutational equilibrium?
    • Stable:
    • Unstable:
    • Neutral:
  21. Migration vs Gene Flow
    Same freaking thing
  22. Define Migration
    The non-random movement of alleles into or out of a population
  23. What are the effects of migration?
    Bring new alleles to the population -> bring new variation to gene pool
  24. 3 types of populations considered by migration are ________ and thier frequencies are__________.
    • Native: with frequencies PnQn
    • Source: PmQm
    • Conglomerate: m+(1-m) (m= migration rate)
  25. What are the two effects of migration?
    • Conglomerate becomes native and a new migration event occurs
    • Conglomerate/Native frequencies asymptotically approach those of the migrant population -> Qm=Qn
  26. What is the "island model" for migration?
    • Migration is 2 way
    • There are many populations
    • All populations can evolve
  27. What are the 4 assumptions of the Island Model?
    • All populations are on discrete "islands"
    • All populations are equal in terms of size, migration rate, etc... (migration rate should remain constant)
    • ...but p and q do not have to be the same in each pop at the start
    • The number of populations is very large (infinite)
    • Island distances are not a factor
  28. Gene flow alters frequencies ____?____ populations.
    Within
  29. Gene flow ___?___ genetic differences __?__ populations and is known as the "__?__."
    • Reduces
    • Among
    • Great Homogenizer
  30. Gene flow __?__ speciation which __?__.
    • Retards
    • Requires Genetic Divergence
  31. What eliminates the homogenizing effect of gene flow?
    Geographical isolation.
  32. "Real" populations subject to genetic drift becuase _____.
    • real pop are:
    • finite and can be very small
  33. Define: Genetic Drift
    Random sampling error of gametes resulting in fluctuations in allelic frequencies from one generation to the next.
  34. __?__ is another name for genetic drift.
    Sewell Wright effect
  35. Random sampling error is a result of __?__.
    Observed outcomes that are different from expected probabilities due to random chance.
  36. __?__ is a measure of random sampling error and gets __?__ as k gets __?__.
    • Variance
    • smaller
    • larger
    • (sigma)^2=pq/k
  37. Genetic drift is __?__ so direction and magnitude cannot be __?__.
    • Random
    • Accurately Predicted
  38. The long term effect of genetic drift is __?__
    loss of one allele while the other becomes fixed
  39. __?/?__ is a function of population site.
    fixation/loss rate
  40. genetic drift causes variation among populations to __?__
    increase
  41. The two special cases of genetic drift are __?__ and __?__.
    • Bottleneck effect
    • Founder effect
  42. The Bottleneck Effect is __?__.
    when populations undergo a drastic reduction in population size (N)
  43. The bottleneck effect results in __?__ and __?__.
    • change in allele frequency
    • loss of genetic variation
  44. How is variation lost from bottleneck restored?
    Genetic flow/Migration or Mutation (very slow)
  45. The Founder Effect is __?__
    when a new population is established from a small number of "founders"
  46. The founder effect results in __?__ and __?__.
    • different allele frequencies in founder populations
    • low variation in founder population

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