Name____________________________________ Date________________ Hour________________

GENETICS COMPUTER SIMULATIONS – SEX LINKAGE

GENETICS CD - 8

Directions: Obtain a CD entitled "Biology Explorer 3.04 Genetics" and a coin from your instructor. Go quietly to the Media Center computer lab. Insert the CD and then complete the following activity. Return the CD to your instructor when finished.

PURPOSE: To discover how inheritance patterns are affected when the gene for a trait is on the sex chromosomes.

PROCEDURE:

    1. Go to the START MENU.
    2. Place your cursor on PROGRAMS.
    3. Move your cursor to "LOGAL Biology Teacher."
    4. Click on GENETICS MAIN MENU.
    5. Click on "CORE INQUIRIES."
    6. Click on "SEX LINKAGE."
    7. <<At this point, the arrows to move around through the program are at the very bottom of the screen. We may have to grab and drag the Start menu tool bar downward until we can’t see it any longer in order to uncover the arrows we need.>>
    8. Follow the directions on each page to complete the exercise. Blue "hyperlinked" words in the directions text can be clicked on to perform certain functions.

QUESTIONS AND DATA TABLES:

  1. What would you predict the genotypes and phenotypes of the offspring to be?

    2. PREDICTED % OF AA OFFSPRING__________________________

    PREDICTED % OF Aa OFFSPRING__________________________

    PREDICTED % OF aa OFFSPRING__________________________

  2. Predicted ratio of red-eyed to white-eyed offspring __________________________
  3. Data table one:
    4.

    SAMPLE SIZE

    NUMBER OF RED EYES

    NUMBER OF WHITE EYES

    RATIO

  4. How does the observed ratio match your predicted ratio?

    5.  

     

     

     

  5. Now consider the second, a reciprocal cross. What would you predict the phenotypic ratio of the is cross to be?

    6.  

     

     

  6. Data table two:
    7.

    SAMPLE SIZE

    NUMBER OF RED EYES

    NUMBER OF WHITE EYES

    RATIO

  7. How doe the observed ratio match your predicted ratio?

    8.  

     

     

  8. What is puzzling about the two reciprocal crosses?

    9.  

  9. Before running the F1 x xF1 cross, predict the F2 genotypes and the phenotypic ratio?

    10. PREDICTED % OF AA OFFSPRING__________________________

    PREDICTED % OF Aa OFFSPRING__________________________

    PREDICTED % OF aa OFFSPRING__________________________

  10. Predicted ratio of red-eyed to white-eyed offspring ________________________

    11. 11. Data table three: What are the observed phenotypes and the phenotypic ratio…

    SAMPLE SIZE

    NUMBER OF RED EYES

    NUMBER OF WHITE EYES

    RATIO

  11. How does the observed ratio match the expected ratio?

    12.  

  12. How does this result compare with what you would normally expect?

    13.  

  13. Complete a Punnett square for a cross between a male (XY) and a female (XX)

    14.  

     

     

     

     

     

     

  14. What is the ratio of male to female offspring?_______________________
  15. Which parent gives the X chromosome to female offspring_______________________
  16. Which parent gives the X chromosome to the male offspring? _______________________
  17. Could it be that the gene for eye color is located on the X chromosome? _______________________
  18. Explore this hypothesis by filling in the a Punnett square (draw your own) for your P x P cross of couple # 1 from the previous section.

    19.  

     

     

     

     

     

  19. What is the expected ratio of red-dyed to white-eyed offspring in the F1 generation, in the different sexes?

    20.  

     

     

  20. Data table four:
    21.

    RED-EYED OFFSPRING

    WHITE-EYED OFFSPRING

    MALES (XAY)

    MALES (XaY)

    FEMALES (XAAY)

    FEMALES (Xa,Xa)

  21. Now draw a Punnett square for the F1 x F1 cross.

    22.  

     

  22. What is the expected ratio of red-eyed offspring in the F2 generation, in the different sexes?

    23.  

     

     

  23. Data table five:
    24.

    RED-EYED OFFSPRING

    WHITE-EYED OFFSPRING

    MALES (XAY)

    MALES (XaY)

    FEMALES (XAAY, XAXa)

    FEMALES (Xa,Xa)

  24. How does this expected result compare with your puzzling results in the F2 generation?

    25.  

     

  25. Predict the results of this cross (XXaY male and XAXa female.)

    26.  

     

     

  26. What is the overall predicted phenotypic ratio, red-eyed to white-eyed?

    27.  

     

     

  27. Data table six: What is the predicted ratio of males to females for each phenotype?
    28.

    PREDICTED RATIO

    OBSERVED RATIO

    RED-EYED OFFSPRING

    MALE;

    FEMALE;

    WHITE-EYED OFFSPRING

    MALE:

    FEMALE:

  28. Data table seven:
    29.

    PREDICTED RATIO

    OBSERVED RATIO

    RED-EYED OFFSPRING

    MALE;

    FEMALE;

    WHITE-EYED OFFSPRING

    MALE:

    FEMALE:

  29. How do your predicted and observed results compare?

    30.  

     

     

  30. Data table eight:
    31.

    MALE GENOTYPE

    (SPOTTED WINGS)

    FEMALE GENOTYPE (CLEAR WINGS)

  31. Predict the phenotypes and phenotypic ratio of males and females in the F1 offspring, and the F2 offspring

    32.  

     

     

  32. Data table nine:
    33.

    CLEAR

    SPOTTED

    F1 GENERATION

    MALE;

    FEMALE;

    F2 GENERATION

    MALE:

    FEMALE:

  33. How do your observed and predicted results compare?

    34.  

     

     

     

     

  34. Predict the phenotypic ratio of males and females in the F1 and F2 generations.

    35.  

     

     

     

     

  35. Data table ten:

CLEAR

SPOTTED

F1 GENERATION

MALE;

FEMALE;

F2 GENERATION

MALE:

FEMALE:

 

 

 

 

 

 

 

36. To summarize, compare your findings in F1 and F2 for a gene located on a sex chromosome to those for a gene located on an autosome.