Law of Genetic Equilibrium Multiple allele(iA,i, i) Blood group A B o AB Genotype AlA jAi ibis iBi ii Atb Genotypic frequency p2+2pr q2 +2qr pg f(I4)=卩 1十q+r f(r)=9 f(1)=/(+q+n2=p2+2p+q2+2pr+r2+2r=1
p＋q＋r ＝ 1 (p＋q＋r) 2＝p 2＋2pq＋q 2＋2pr＋r 2＋2qr＝ 1 Multiple allele (I A , I B , i) f (I A) = p f (I B) = q f (i) = r Law of Genetic Equilibrium Blood group A B O AB Genotype I AI A, IAi I BI B, IBi ii I AI B Genotypic frequency p 2＋2pr q 2＋2qr r 2 2pq
Law of Genetic Equilibrium Ⅹ- linked alleles Males: f(XA)=1 3p; f(Xa)=1/ 3q XAY xar Females:f(X4)=2/3=23p(p+q)=2/3p2+2/3pq f(X)=23q=23q(p+q)=2/392+2/3pq XAXA= 2 3p; XAXa= 4 3pg: Xaxa= 2/3 q2
Law of Genetic Equilibrium Females：f(XA) ＝2/3p Males：f(XA) ＝ 1/3p; f(Xa ) ＝1/3q f(Xa ) ＝2/3q＝2/3q(p＋q)＝2/3q 2＋2/3pq XAY XaY XAXA＝ 2/3p 2 ; XAXa ＝ 4/3pq; XaXa ＝ 2/3q 2 ＝2/3p(p＋q)＝2/3p 2＋2/3pq X-linked alleles
Law of Genetic Equilibrium Ⅹ- linked alleles Ⅺ(p) x(q X(p) XAXA(p XAX(pq n XYp X( XAxa(pq) Xaxa(q) xar(g Females: Frequencies are the same for any other locus: (p2+2pg+g2) Males: Genotype frequencies are the same as allele frequencies:(p+ q
XA (p) Xa (q) Y XA (p) XAXA (p 2 ) XAXa (pq) XAY (p) Xa (q) XAXa (pq) XaXa (q 2 ) XaY (q) Females: Frequencies are the same for any other locus: (p 2 +2pq + q 2 ) Males: Genotype frequencies are the same as allele frequencies:(p + q) Law of Genetic Equilibrium X-linked alleles
Derivation ad diseases Affected of Heterozygote q ≈1 +2 pg Affected %s Almost all of the affected are heterozygote
Affected 2pq p 2 ＋ 2pq ≈ 1 Derivation AD diseases Affected of Heterozygote ❖ Almost all of the affected are heterozygote
Derivation ar diseases 2p=2q(1-q)=2q-2q2≈2q 2pg≈2q g The heterozygote carrier frequency is twice the frequency of the mutant allele
2pq ＝ 2q － 2q ＝ 2 2q(1－q) ≈ 2q 2pq ≈ 2q ❖ The heterozygote carrier frequency is twice the frequency of the mutant allele. Derivation AR diseases