2.5 Linkage, 3-point analyses from test cross

- Put your observed number of gametes from a test cross and click the Evaluate button.

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In all cells with initial values you shall put your data (green fields) and to get the results press the Evaluate button. You can change the gene symbols (yellow fields) if you like.

You can change phase of the gene in first row by using the Repulsion button
or change order of the genes using the A<-->B (change row 1 and 2) or B<-->C (change row 2 and 3) buttons.
These buttons can be used until you have the desired result - that is the parental gametes and the double cross overs have the correct gamete type corresponding to your observations.
Analyses can only be meaning full if you have identified the paternal gametes (those with highest numbers of observations) and the double cross over gametes (those with lowest numbers) .
Data for the single cross over AB and BC are put in column 2 and 3 as shown in the initial data.

Example: The data shown in the initial example do have the parental genes as shown, where as the Double cross over (DCO) have gametes A1B1C0 and A0B0C1. So the order of the genes are apparently not ABC as the initial values are set. The correct gamete type can be achieved by pressing the button B<-->C, which then give the correct order of the genes A-C-B. With the distances A-C 24, B-C 18 and A-B 42 cMorgan which you get after pressing the Evaluate button
Questions:
Calculate the linkage in cM and give the order between the genes A, B and C. 

Gamete  Observed frequency
aBC       221
Abc 	  235
ABC	  105
abc	  95
ABc	  56
abC	  61 
AbC	  19
aBc       14

Remember: Parental gametes have always the highest number of observations, and DCO's the lowest. There are only three possible orders of the genes A-B-C, B-A-C and A-C-B.

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