Answer:
15 m.u.
Explanation:
The genes for fruit and flower color are located in the same chromosome and we have to determine the distance between them.
The initial cross between two homozygous individuals with different traits resulted in an homogeneous F1 with red fruit and yellow flowers. Because of Mendel's Law of Uniformity, we know that the red fruits and yellow flowers are the dominant alelles.
I will call:
R_ = red fruit
rr = golden fruit
Y_ = yellow flowers
yy = white flowers
<h2><u>Initial cross:</u></h2><h2>
P RY/RY x ry/ry</h2><h2>
F1 RY/ry</h2>
All F1 tomato plants have red fruit and yellow flowers because they have the R and Y alelle.
<h2><u>Test cross:</u></h2><h2>
RY/ry x ry/ry</h2><h2><u>
</u></h2>
The gametes produced by the homozygous individual can only be ry.
The gametes produced by the heterozygous individual can be:
RY - Parental
ry - Parental
Ry - Crossover
rY - Crossover
<u></u>
<h2><u>
F2 progeny:</u></h2>
41 RY/ry (Parental, Red fruit and yellow flowers)
44 ry/ry (Parental, Golden fruit and white flowers)
7 Ry/ry (CO, Red fruit and white flowers)
8 rY/ry (CO, Golden fruit and yellow flowers)
Total= 100.
The formula to calculate genetic distance is:
Genetic Distance (m.u.)= Recombination Frequency X 100.
<u>The recombination frequency is calculated as the number of crossover individuals divided by the total number of individuals.</u>
Replacing the results in the formula, we have=
Distance = (7 + 8)/100 x 100
Distance = 15 map units.
