F Repulsion Progeny Part II

The A_B_ class has the proportion (p +2)/4 for repulsion linkage. Now let us find the proportion for the other three classes.

class	proportion	A_bb phenotype
AAbb	(1-p) 4
Aabb	p(1-p) 4
Aabb	p(1-p) 4

(1-p) + p(1-p) + p(1-p) = 1 - 2p + p + p - p + p - p
  4           4          4                         4

= -p + 1 = 1 - p
        4         4

class	proportion
aaBB	(1-p) 4
aaBb	p(1-p) 4
aaBb	p(1-p) 4

(1-p) + p(1-p) + p(1-p) =  1-p 
              4                        4

Finally there is only one combination that results in the aabb genotype with probability p/4.

Example

We can sum the probability of all genotypes that are phenotypically A_B_ or A_bb or aaB_, or aabb.

class	A_B_	A_bb	aaB_	aabb	Total
observed	a	a	a	a
observed	753	292	351	19	1415
expectation	p2 + 2 4	1-p2 4	1-p2 4	p2 4

r = n, s = -a + 2a + 2a + 2a, t = -2a

r = 1415, s = -753 + 2(292) + 2(351) + 2(19) = 571, t = -2(19) = -38