Populatiegenetica

 

                    onderzoek genenpool populatie

                                        bv. hoeveel rhesuspositieven drager van negatief allel ?

 

                                           

                                                Weinberg                                    Hardy

 

                                                Wiskundig model

                                        In populatie: AA, Aa en aa

                                                              frequentie allel A in genenpool is p

                                                             frequentie allel a is q

                                                            AA: zaaadcel A  x  eicel A

                                                            frequentie AA dus p x p = p2

                                                            aa: idem

                                                            frquentie dus q x q = q2

                                                            Aa: zaadcel A  x  eicel a  of omgekeerd

                                                             frequentie Aa dus 2 x p x q = 2pq

 

                                    Som frequenties allelen is 100% of 1   ▬►  p + q = 1

                                    Som frequenties genotypes eveneens 1  ▬►  p2 + 2pq + q2 = 1

 

                                    Voorbeeld

                                    16 %     rhesusnegatief  (positief dominant)

                                                 q2 = 16% of  0,16  q = 0,4

                                                 p + q = 1   dus  p = 0,6

                                                 p2 = 36%  en  2pq =  48%   of  84 % rhesuspositieven

                                    Hoeveel drager negatief allel?

                                    Van de 84 positieven zijn er 48 drager = 57 %

                            Problemen bij zwangerschap

                            1. vader positief (AA) - moeder negatief (aa)

                            2. vader positief (Aa) - moeder negatief (aa)

 

                             1. kinderen Aa   ▬ freq. huwelijken                                                                                                                                 p2 x q2 = 0,36 x 0,16 = 0,0576 = 5,76%

                             2. kinderen Aa en aa   ▬ freq. huwelijken

                                                                         2pq x q2 = 0,48 x 0,16 =  0,0768 = 7,68%

                                                                         kind 1 kans op 2  ▬7,68 : 2 = 3,84%

 

                        └    9,6% in populatie potentieel gevaarlijk betreffende rhesusfactor