Linkage Studies - Part I
| Source
of Data |
Amount
of Information per individual(i) |
|
| Repulsion:
testcross |
1
p(1-p) |
| |
|
| F2 |
2(1+2p2)
(1-p2)(2+p2) |
|
For coupling data we use the same formulas, but substitute
1- p for p.
I = 1 / Vp = ni
Example A:
Let p = 0.4, evaluate the amount of information for testcross vs F2
data with repulsion linkage. Let n = 1000.
Testcross I = ni; i = 1 / [p(1 - p)] = 1 / (0.4 x 0.6) =
4.167
I = 1000(4.167) = 4167
| F2 I = ni i = |
2(1 + 2p2) |
= |
2(1 + 2(0.16)) |
| (1 - p2)(2 + p2) |
(0.84)(2.16) |
| |
|
|
|
| |
|
= |
2.64 |
= 1.46 |
| |
|
1.814 |
| I = ni |
= 1000(1.46)
|
|
| = 1455.3 |
|
The results show that 1455/4167 = 0.35 which means that in this example
F2 repulsion data only provides 35% as much information
as testcross data.
