Three point test cross

[pensive]

Hi,

 

I was given a workshop on how to do a two point test cross. But the lecturer didn't go over three point. I went off to do it by myself and spent hours trying to work. Long story short, I got the progeny for cross like this.

 

V (vermillion) cv (crossveinless wings) (ct (cut wing edges) --> mutant alleles

 

Wily type--> + (red eyes) +(cross veined) + ( normal wings)

 

v ct cv/ + + + (arbitrarily ordered female) x V ct cv/ v ct cv (male)

 

I got 8 progeny from double and single crosses.

 

 

v + + = 580

+cv ct = 592

 

Those were the parental

 

V cv +=45

++ct=40

v ct cv=89

+++=94

 

single crosses

v+ct=3

+cv+=5

double crosses

 

and total progeny 1448

 

 

Anyway, I worked out that the ct allele should have been in the middle in all of the above genotypes. by reordering the parental chromosome. But the bit I'm stuck on is calculating the map units.

 

The alleles in the female were thus arranged like this v++/+ct cv in this exact order.

 

 

So I was told to look for the V-ct loci and then work out the RF for this, but how do I do that?

I need to do this for ct-cv and v-cv loci as well.

 

 

Please could someone help me. I really,really,really stuck and annoyed because I want to work this out!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

 

Cheers

Edited March 25, 2012 by pensive

[pensive]

no one helped

 

no one helped