again I need to know how to do these by hand Two different traits affecting pod

Question

again I need to know how to do these by hand

                 Two different traits affecting pod characteristics in garden peaplants are encoded by genes found on chromosome 5. Narrow podis recessive to normal pod; yellow pod is recessive to greenpod. A true-breeding plant with narrow, green pods wascrossed to a true-breeding plant with normal, yellow pods. The F1 offspring were then test crossed to plants withnarrow, yellow pods. The following results were obtained:

narrow greenpods      144

normal yellowpods     150

narrow yellow pods     11

normal greenpods           9

           How far apart are these two genes? Assign your own gene symbols

Map distance between

Map distance between

Explanation / Answer

I haven't done these using two characteristics but I will domy best to assist you. if normal is dominant than N=normal and n=narrow and if greenis dominant G=green and g=yellow. A cross between true breeding narrow and green = nnGG tonormal and yellow NNgg. This yields NnGg because there is a 4:4ratio of Nn in a cross of nnxNN and 4:4 ratio of Gg between GGxgg.This is TEST CROSSED not self-crossed. A test cross uses homozygousresessive. So we would have NnGg x nngg. Looking at the data, place the numbers in order andassign letters so 150 nG, 144 Ny, 11 ny, and 9 NG. The one with thelargest number of offspring is the parental and the one with theleast is your double crossover. Looking at the parental and DCO wehave nG and NG, only the n gene is changing so this would be your"middle" gene in a 3 point cross. If I take this problem like a 3point cross than you want to take your middle 144 and 11, add themtogether, and divide by the entire offspring numbers to get thedistance between the two genes. I'm sorry if this is confusing, butit might give you something to think about. Your genes are n and gthat you need to find the distance to.

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