How to mate flies – virtually!

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• go to www.biologylabsonline.com and

Create a 1-day free trial

• Use your email address to create a one-day free trial. The site will email you a password. You will then have 24hrs. to use the site before the password expires.

• You must complete the procedure in that time. Usually, for the first time, it takes about 20-30min.

Autosomal recessives

Bristle - SpinelessBody Color - Black, EbonyEye Color - Brown, Purple, SepiaEye Shape - EyelessWing Size - Apterous, Vestigial Wing Shape - Curved, DumpyWing Vein - Incomplete veins

Sex-linked recessives

Body Color - Tan, YellowWing Size - MiniatureWing Shape - ScallopedWing Vein - Crossveinless

1. Select offspring total

– Choose either 1,000 or 10,000 offspring– Click the “Design” button underneath the grey

image of the female

2. Select parent phenotypes

• Browse through the range of phenotypes• The image below shows a preview of what the

mutations look like – Some mutations

you see are recessive, someare also sex-linked

2. Select parent phenotypes

• Use the handout to guide you in selecting one male and one female

• To erase a selection, click the “Reset All” button to make the fly Wild-type (+) againwild-type: organism with no

introduced mutations

2. Select parent phenotypes (contd.)

• Select phenotypes for both sexes until a colored image appears for each

• If you make a mistake, click the “Remove” button, then “Design” to select again

3. Mate parents

• Once you have chosen both parent phenotypes,click the“Mate” button

4. View F1 results• on the next screen, you will see the F1

results– Did you do it

correctly?All your F1’s should be wild type flies

5. Mate F1’s

– Click “Select” button under each image

– F1’s now become parents of the next generation

– Click the “Mate” button

– you now see F2’s, note the N= giving you the number of each phenotype

– to see more F2’s, click the down arrow

6. View F2 results

6. View F2 Results

– If you see “2 fly images” or “4 fly images” there are more F2 phenotypes to see

– continue clicking down to see more F2 phenotypes

7. Analyze results– In the lower left-hand

corner, click the “Analyze Results” button

– You now see the total flies of each phenotype in a table, along with the proportions (percentages) of the total population. The ratios of phenotypes are also shown.

– Skip to step 10 to print this out

8. Make predictions

• Write down the TOTAL population number on a piece of scratch paper

• Click on the “Chi-Square Analysis” tab

8. Make predictions

• Then, divide this number evenly among males and females. Ex. 759/2 = 379.5**

*To see the total population, click the “Summary of Results” tab**it does not matter if we use a fraction here – this is only a probability,

not an actual number of organisms

Enter in the expected numbers. These would be based on the total population. For example, if you expect 75% to be wild type and the total F2 population* was 1012, multiply:

1,012 X 0.75 = 759

8. Make predictions

When all fields are correctly filled

in, click “Test Hypothesis”

9. View Chi-Square Results

• The final screen shows the Chi-square analysis performed by the program

• These numbers will be discussed in class

• For now, you want to print the results

Chi-square value

10. Print results

• To print your results, click the “Add Data to Notebook” link in the upper-right hand corner

• This pulls up a new window showing the data collected

*If you don’t see

anything in the window, use

the scroll bar to move up/down

• Click “ExportNotes”

10. Print results

• The results show up in a new browser window (HTML page). Print this page once.

You’re done!