In Neurospora,an Irish Strain Makes Big as Well as Green-Colored

Essay

In Neurospora,an Irish strain makes big as well as green-colored colonies (genotype b g).It is crossed to a wild-type strain,which makes small and orange-colored colonies (genotype: + +).The following ordered tetrads of asci were found,with the numbers of each type indicated below each tetrad.
$$\begin{array} { l l l l l l l } \text { I}& \text { II } & \text { III } & \text { IV } & \text { V } & \text { VI } & \text { VII } \\b g & b + & b g & b g & b g & b + & b g \\+ + & + g & + + & + g & b + & b + & b g \\+ g & b + & b g & b + & + g & + g & + + \\b + & + g & + + & + + & + + & + g & + + \\\hline 4 & 1& 24 & 1 & 91 & 2 & 177\end{array}$$
a)Classify the asci above (I-VII)according to type.
(i) those which are PD
(ii) those which are NPD
(iii) those which are $\mathrm{T}$

b)Calculate the percent recombination between b and its centromere.
c)Calculate the percent recombination between g and its centromere.
d)What is the most likely map of the two genes in relation to each other and to the position of their respective centromere(s)?