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.

    54/344 (page 38)
    The gene for baldness (B, say) is dominant in man but recessive in women so that the baldness is more common in men than in women because among men the proportion of baldness is p 2 + 2 p q while among women the proportion is only p 2 . If p is comparatively small, the values of these two proportions will differ widely. Genotype BB Bb bb Proportion p 2 2pq O r Men bald bald normal B dominant Women bald normal normal b dominant « From the above scheme, we see that q — Vproportion of normal men among male-population P = V proportion ot bald women among female-population. These two estimates for gene frequencies based on the two sexes should add up to unity if our genetic hypothesis for human baldness is correct. Note that these two estimates are all based on the proportion of récessives in population. As an example of practical application, the following data from Snyder's book is cited : Bald Normal Size of sample Men .4296 .5704( = Ä) N i W omen .0775 (=r) .9225 n 2 Hence, our estimates are q = »/T57Ü+ = 0.755 *) > Sum — 1.033 p = »/.0775 = 0.278 3 which agree with the theory fair closely. The standard deviation of the discrepancy between the^calculated sum of p and q and the theoretical unity is (Snyder, 1934) 0- . - 1 yr 1 ^ tl-rr^ N / 1 - r _ a -ZlPj T- dls P 2 V V jvi 16rNf ) V N 2 16 R Ni J