If I tell you a map looks like this A B C a10b20c What is th

If I tell you a map looks like this A B C a----10----b--------20----c What is the probability of each of the 8 possible gametes? Remember the probability of no crossover is 1-mapdistance%, ie a-b 90% no crossover remember to account for all the products

Solution

Answer:

The 8 possible gametes are:

1. ABC

2. abc

3. Abc

4. aBC

5. ABc

6. abC

7. AbC

8. aBc

(For 1 and 2) Frequency of the parental gametes = 1/2 * (no CO A-B) * (no CO B-C)

= 1/2 * (1-0.10) * (1-0.2) = 1/2 * 0.9 * 0.8 = 0.36

So, frequency of gametes ABC and abc = 0.36 + 0.36 = 0.72

(For 3 and 4) Frequency = 1/2 * (CO A-B) * (no CO B-C)

= 1/2 * (0.1) * (1-0.2) = 1/2 * 0.1 * 0.8 = 0.04

So, frequency of gametes Abc and aBC = 0.04 + 0.04 = 0.08

(For 5 and 6) Frequency = 1/2 * (no CO A-B) * (CO B-C)

= 1/2 * (1-0.1) * (0.2) = 1/2 * 0.9 * 0.2 = 0.09

So, frequency of gametes ABc and ABc = 0.09 + 0.09 = 0.18

Sum of frequencies of gametes (1-6) = 1- (0.72 + 0.08 + 0.18) = 0.98

So, combined frequencies of gametes (7-8) = 1-0.98 = 0.02

So frequencies of gamete 7 and 8 individually = 0.02/2 = 0.01