Franz Boas -Heredity in Head Form

HEREDITY IN HEAD FORM BY FRANZ BOAS T he recent discussio n o f Mendel’s law has called rene wed at ten - tion to th e phenomena o f heredity. In anthropology this problem has been discussed principally by Galton and Pearson who have treated their materials according to th e method of correlations. T h e principle o f this method requires two assumptions : first t ha t each parent has a certain influence upon the form of each offspring and th at the amount of this infl uenc e remains the same in all cases except t hat it is subject to chanc e variations ; second that the variability o f th e o ffspring does not depend on the form o f the parent.‘ If Mendel’s law holds good even in a restricted way in the human species these assumpt ions would not be admissible on account o f th e dominan t influence o f one parent or th e other and the results o f the method of correlation could be considered as rough approxi- mations only. If we assume that the influ ence o f one parent dominates we must expect to find a massing of the measurements of descendants at points corresponding to those of the parental measureme nts. There- fore th e great er th e diff ere nce between the parents the greater m us t be th e va riabi lity of the offspring. T h e characte r o f the laws of heredity can therefore be determined by an investigation of the question whether the variability o f th e offspring depends upon th e difference between the parents. I was led to t ake up this quest ion by an observation whi ch I had published in I 894, in a stu dy o f t he half-blo ods o f the American and European races2 I found that in this case there is a de cided tendency to develop a width of face tha t corresponds either to that of the European or to that of th e American race whil e intermediate forms are rare. This phenomenon conforms to Mendel’s law. 1 See Franz Boas, I The Cephalic Index,” American AnthropoZogist N . s., vol. I, pp. 448-461. PopuZar Science Monthly, October, 1894, pp. 761-770. 5 3 0

Franz Boas -Heredity in Head Form

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