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  1. principle of segregation
    • That the alleles from a single gene will be segragated upon the formation of a sex cell. A new generation is formed when sex cells from two come together in fertilization, upon fertilization the ddiploid number of chromosomes is restored, one allele from the father(paternal) one allele from the mother(maternal).
    • Proved this through monohybrid crosses
    • Always saw 3:1 in F2 generation
  2. A test cross of a F1 heterozygous with a homozygous recessive parent.
    • Always produced a 1:1
    • this ratio told him that his F1 plants were heterozygous, they recieved an allele from one parent and a different one from the other.
    • Dominant phenotypes appear in F1 generation
    • recessive not seen in F1
    • F2 generation dominant seen in 3/4
    • F2 generation recessive seen in 1/4
  3. Principle of independent assortment
    • dyhybrid crosses
    • when dealing with two traits the two genes that control those traits do not control eachother. The two genes are independent.
    • Only true if genes are seperate chromosome or genes are far apart and can be affected by crossing over
  4. Dyhbrid crosses
    • Two traits, the parents are different for the traits
    • F1 generation show dominant
    • F2 generation 9:3:3:1
    • Test cross- heterozgous F1 plant to a homozygous recessive parent, 1:1:1:1
  5. Exception to principle of independent assortment.
    • Linkage
    • two genes close together on same chromosome
  6. Null hypothesis
    • The two genes are not linked
    • if the null hypothesis is rejected by chi test you excpect the alternitive hypothesis that they are linked
  7. recessive autosomal
    • parent generally not affected
    • can skip generation
    • p[additional offspring] 1/4(parents must be hetero) so offspring has 1/4 chance of being affected
    • 2 affected parents must have all affected offspring
  8. Dominant autosomal
    • 1 parent must be affected
    • can not skip generation
    • p[additional offspring]=1/2 parents hetero and homo noramal)
    • 2 affected parents can have unaffected offspring(p=1/4)
  9. TDF
    • Testies determining factor
    • protien that tells gonads to develope into testies
  10. Example of Y linked
    Long hairs growing from ear, all sons have to have the trait
  11. X linked
    dominant or recessive
  12. X linked Dominant
    • Does not skip generation more common in female then in males
    • 1/2 children from affected female(hetero) will be affected
    • all duaghters from affected male will be affected, no sons will
  13. X linked recessive
    • Can skip generation, more common in male then in female
    • all sons of an affected female are affected
    • 1/2 sons of carrier female are affected
    • female is affected only if her father is affected and her mother is at least a carrier
  14. One gene two alleles Complete dominance
    • F2 generation 1:2:1
    • alles under complete dominance F2 generation 3:1
    • Test cross 1:1
    • Haplosufficent-only need one copy of the dominant allele to express the dominant phenotype
  15. One gene two alles Incomplete dominance.
    • Genotype ratio F2 1:2:1
    • Phenotype F2 generation 1:2:1
    • test cross 1:1
    • Dose effect- one allele produces functional protien, the other allele produces no protien or null allele
    • EX- Flower color, homozygous dominant red flowers, hetrozgous pink flowers, homo rec white flowers
  16. one gene two alleles Codominance
    • genotype 1:2:1 F2
    • Phenotype 1:2:1 F2
    • testcross 1:1
    • EX- human blood typing- type AB blood and you make glycoprotien on surface of blood cell called aglycoprotien, you also make bglycoprotien so cell can make both protiens
  17. Multiple allele one gene
    • n(n+1)/2 predicts genotype in population
    • human blood types A,B,C 3(3+1)/2=6
  18. One gene several phenotype
    • Leathal gene
    • EX- yellow coat mice(not born),hemophilia(are born), Huntingtons( are born)
    • Leathality varies
    • F2 generation 2:1(2 not born, 1 live to pass it on)
  19. pleitrophy(one gene several phenotypes)
    • one gene affects many different phenotypes
    • EX-cycle cell animia,cant get malaria
  20. Enviomental effects (one gene many phenotypes)
    • phenocopy-the enviorment has caused a phenotype that could of been caused by a genotype, EX-drug given to pregnent women was producing a phenotype that could of been caused by a genotype.
    • Penetrance-frequency at which a paticular genotype produces an expected phenotype
    • Expressivity-dagree to which a genotype is expressed
    • Norms of Reaction-a set of enviormental phenotypic relationships for a given genotype
  21. Enviormental effects (one gene many phenotypes)
    • Sex linked-traits controlled by genes carried on one of the sex chromosomes, EX-red green colored blindness
    • Sex limited-have phenotype that only occur in only one gender EX-cattle only male have horns
    • Sex influenced-are triats controlled by genes carried on autosomes EX-male pattern baldness
  22. Enviormental effects(one gene many phenotypes)
    Tempeture-EX himilian rabbit ice on back hair goes black
Card Set
test 2
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