Please show all work, thank you!! 5. A nic+ ad haploid strain of Nerurospora is

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Please show all work, thank you!!

5. A nic+ ad haploid strain of Nerurospora is crossed with a nic ad+ haploid strain. A total of 1000 ordered tetrads are isolated and categorized as follows: 2 3 4 5 6 7 nic+ ad nic+ad+ nic+ ad+ nic+ ad nic+ ad nic+ ad nic+ ad+ nic+ ad nic+ad+nic+ad+nic+ ad nic+ ad nic+ ad+ nic+ ad+ nic+ ad nic+anic+ adnic ad nic ad+ nic ad nic ad nic+ ad nic+ ad+nic+ adnic adnic ad+ nic adnic ad nic ad+ nic ad nic ad+nic ad nic ad+nic ad nic ad+nic ad nic ad+nic+ad+ nic+ adnic+ ad+nic+ ad nic ad+nic+ad nic+adnic+ ad+nic+ ad nic ad nic ad+ nic ad nic adnic ad+ nic ad nic ad+nic ad+ nic adnic ad+ 94 800 95 4 5 Determine the relative order the nic and ad genes relative to each other and to the centromere

Explanation / Answer

Out of seven different types:

Parental Ditypes (containing nic+ ad and nic ad+ combination just like parents) = tetrad type 1 and type 5

Total Parental Ditypes (PD) = 800 + 94 = 894

Non Non Parental Ditypes (containing nic ad and nic+ ad+ combination) = tetrad type 2 and type 6

Total Non Parental Ditypes (NPD) = 1+ 1 = 2

Tetratypes (containing nic+ ad, nic ad+, nic ad and nic+ ad+ combination just like parents) = tetrad type 3, type 4 and type 7.

Total tetratypes (TT) = 95+4+5 = 104

Total tetrads = 1000

Recombination frequency = [(1/2 x TT) + NPD]/total tetrads

= [(1/2 x 104) + 2]/1000 = [52 + 2]/1000 = 0.054.or 5.4%

i.e. these two genes are 5.4 map units apart.

Now as PD >> NPD It indicates the genes are linked and hence are present on same side of centromere.

conclusion:

nic and ad are present on same side of centromere and are 5.4 map units apart.

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