An introduction to population genetics / by Ching Chun Li.

  • Li, Jingchun.
Date:
1948
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: An introduction to population genetics / by Ching Chun Li. Source: Wellcome Collection.

    56/344 (page 40)
    (p2)Z> . (2pq-)H . (q2)R, the logarithm of which is L = D log p 2 + H log 2 p q R log q 2 = 2 D log p -f H log 2 p ^1 — p) + 2 R log (1 — p ) dL _ j^D H(1 - 2p) _ 2fi dp p p{l- p) 1 - p Putting = 0, we obtain 2D(1 — p') + H{1 — 2 p) — 2 Rp Ì- M 1 ~ P) that is, 2D — 2 D p + H — 2 Hp — 2 R p = 0 2(D + H + R)p = 2D + H 2D + H '• r = —ïW~- 2. A convenient formula for calculating • Let D, H , and R denote the actually observed numbers of genotypes A A, A a arid a a, respectively and D a , H 0 , and R 0 denote the corresponding theoretically expected numbers, ( D + H+ R = N= D 0 + H 0 + R 0 ) 2= ( D - D o^ 2 , (H - H 0 Y {R-Rp X ^ R 0 2 Since Do = p 2 N= ( 2/ ^+; 7/ ) V if 0 = 2p ,.jv = 2 (i4+£)(24+2)iv . and R o==q 2 N= (2* V y Nt • substituting and simplifying, we get (R. A. Fisher) . 2 _ {H 2 - 4DR) 2 N x [2D + H) 2 (H + 2R) 2 ' % There is only one degree of freedom because, in addition to the usual 42