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Gene Mapping

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Gene Mapping

Postby sez123 » Tue Feb 17, 2009 2:44 am

Singed Bristles (sn), crossvienless wings(cv) and vermillion eye colour(v) are due to recessive mutant alleles of three x linked genes in drosphilia melanogaster. When a female heterozygous for each of the three genes was testcrossed with a singed, crossvienless, vermillion male, the following properties were obtained.

CLASS PHENOTYPE NUMBER
1 singed,crossveinless,vermillion 3
2 crossveinless,vermillion 392
3 vermillion 34
4 crossveinless 61
5 singed,crossveinless 32
6 singed,vermillion 65
7 singed 410
8 wild type 3
TOTAL: 1000
What is the correct order of these three genes on the X chromosome?

I know how to calculate genetic map distances, find interference and coefficient of coincidence, and i cant remember how to find correct order of genes!!!!! Since this is the most simple question, and must be known, i think, to find distances etc, i would love your help!!
thanks
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Last edited by sez123 on Tue Feb 17, 2009 4:32 am, edited 1 time in total.
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Postby mith » Tue Feb 17, 2009 3:42 am

draw out the crossings(recombinants), the distances will tell you.
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Postby sez123 » Tue Feb 17, 2009 4:34 am

I attempted this but the distances i found seem to make no sense...perhaps you can see what i am doing wrong?
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