Mutation and Genetic Variability

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Mutation and Genetic Variability
2013-09-24 09:31:11
Biology GRE

Biology GRE
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  1. How are genes added to the pool
    How are they removed from the pool
    • Added- Mutations, gene flow, genetic recombination
    • Remove- natural selection
  2. Mutation
    • Create new alleles from preexisting ones
    • Genetic recombination also shuffles around genes and makes new ones
    • *Only mutations on germ line, can be passed onCells that make gametesStomatic mutations never are passed on
  3. Neutral Mutation
    One in a non coding section of DNA
  4. Beneficial Mutation
    • Helps the organism in some way
    • Ex: leads to building twice the amount of protein it needs
  5. Gene Translocation
    • Moves a gene from one chromosome to another
    • *If closer to the promoter that may be benefical
  6. Polymorphism
    • More than one form or phenotype
    • Black and brown fur
  7. Continuous Polymorphism
    • No discrete forms, but a spectrum of phenotypes
    • ex: skin color
  8. Non continuous Polymorphism
    • Discrete forms
    • EX: blood type
    • A, B, AB, O
    • You are one of the four not somewhere in the middle
  9. Balanced Polymorphism
    • When two or more phenotypes exist in population for long period of time
    • Usually maintained because individuals choose to mate with same phenotype so they continue the cycle of two or more phenotypes
  10. Heterozygous Advantage
    • One way that balances polymorphisms
    • The individual with mixed alleles (Ss) has advantage
    • ex: Sickle cell anemia, and malaria
    • S- normal hemiglobin
    • s- sickle cell hemiglobin (less O2 carrier)
    • Malaria only effects S
    • SS- fall sick to malaria easily
    • Ss- Only half cells can fall sick to malaria, but enough S so they dont have sickle cell
    • ss- Have sickle cell anemia

    Allows for continuous births of all three phenotypes, because is Ss most advantageous, cannot have SS or ss become extinct
  11. Frequent Dependant Selection
    • When particular morph loose survival advantage as it becomes more frequent in population
    • Tends to keep balanced polymorphism
  12. Gametic Disequilibrium
    • Linkage Disequilibrium
    • Certain traits may be linked so that traits appear together much more frequently then would happen at random
    • Due to gene linkage relative frequencies differ than what Hardy Weinburg predicts
    • Sexual reproduction and mutations reduce gene linkages
  13. Cline
    Graded Variation across a diversity of climate and other environmental conditions
  14. Ecotypes
    • Local populations that become distinct genetically from other forms
    • Locally adapted population
  15. Transplantation Experiments
    Move a species to a new area to see if they will take hold there