Matthew R Allegretti Week 2

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Week 2 Assignment



The purpose of this lab is to discover how to make a true breeding purple flower.

Methods and Results

Begin with Starting greenhouse

  1. Cross Green 1 and Green 2
    • All Green
  2. Cross Green 2 and Red
    • Some purple
  3. Self cross purple
    • Some purple, not all
  4. Self cross white
    • All white; true breeding
  5. Record crosses of 4 original plants
    1. Green 1 x Green 2
      • 25 Green
    2. Green 1 x Red
      • 10 Green 13 Black
    3. Green 1 x White
      • 27 Green
    4. Green 1 Self
      • 22 Green
    5. Green 2 x Red
      • 4 Purple 10 Blue 6 Yellow 8 Orange
    6. Green 2 x White
      • 13 Yellow 9 Blue
    7. Green 2 Self
      • 7 Green 8 Yellow 8 Blue
    8. Red x White
      • 10 White 12 Red
    9. Red Self
      • 7 White 14 Red
    10. White Self
      • 20 White
  6. List of potential colors and alleles
    • Green BY GG GB GY GW
    • Red RR RW
    • White WW
    • Yellow YY YW
    • Black RG
    • Orange RY
    • Blue BW BB
    • Purple BR
    • Note: White is recessive to all other colors, blue and yellow are recessive when green is present. Purple requires both blue and red.
  7. List of original four strains' genotypes
    • Green 1 GG
    • Green 2 BY
    • Red RW
    • White WW
  8. Try to isolate true breeding colors
    • True red- self breed subsequent generations of red offspring until a true breeding red is reached
    • True green-green 1
    • True white-default white
    • True blue-green 2 x red--> self cross subsequent generations of blue offspring until true blue is reached
    • True yellow-green 2 x red--> self cross subsequent generations of yellow offspring until true yellow is reached
    • True breeding greenhouse‎
  9. Hypothesis 1: True red x True blue will not make true purple
    • True red x True blue offspring were all purple, self cross of purple did not breed true
  10. Hypothesis 2: Mutant Red offspring will result in true purple
    • Purple mutants occur infrequently. Self breeding can result in true purple, but doesn't always result in true purple.
  11. Hypothesis 3:Mutant Blue offspring will result in true purple
    • Mutant blue led to a purple flower, self crossing purple led to white and purple offspring, self crossing subsequent purple offspring led to true purple. Not all mutant purples result in true breeding crosses.
  12. Conclusion: The purpose of this lab was to create a true breeding purple flower. This was accomplished by initially isolating true breeding red and blue flowers. Because purple flowers do not have their own allele that codes for them, it was not possible to produce a true breeding purple flower without inducing mutations in either the true red or blue plants. Even when inducing mutations, not all purple, mutant offspring produced true breeding varieties. This is because mutants could have a number of genotypes after mutating either the true red or blue flowers. In order for the first generation of purple mutants to become true breeding, it would be necessary for both original alleles to mutate into purple mutant genes. Otherwise it was necessary to self breed subsequent generations of purple mutants before arriving at true breeding varieties, as a homozygous (PP) would need to be achieved from a heterozygous purple (PW) and random assortment, often requiring several generations to create a true breeding variety. Any gene combination other than PW or PP does not eventually result in a true breeding purple flower.

Journal Assignment

Week 2 Journal

Data and Files


Assignment Partners

While I worked with the people noted above, this individual journal entry was completed by me and not copied from another source.


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