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.

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    where R is the proportion of récessives (normal, in our example) among men and r is the proportion of récessives (bald) among women and IVj, ¿V 2 are, respectively, the number of women and men examined in the study. For sex-influenced characters, we have just seen that the proportion showing the character in the two sexes are different but closely related so that if we know the proportion in one sex, we may calculate the correspond ing proportion in the other sex. For instance, if we know that there are 31 o/ 0 among men showing the character dominant in males, {e. g. baldness) what proportion of women may be expected to show the character (recessive in females as baldness) ? We see that <7 2 = 1 — .31 = .69 •*. q = /.69 = .8307 Thus, p = l- .8307 = .1693 and p 2 = .0287 or 2.87 % which is the expected proportion of baldness among women. A table based on the above consideration has been give by Snyder and Cotterman (1936). If we let < jj 3 denote the proportion of baldness among men which* is the calculation based on a sample of IV men, the standard deviation of the above estimate is „-(i./i-aff J/**. NOTES 1. The maximum likelihood estimates of gene frequencies : Suppose we have the following sample of N individuals : Genotype AA Aa aa Total Observed numbers D H R N Theoretical proportions <> P 2 pq 9 r 1.00 The probability of observing such a set of numbers is 41