Full text: Problems in eugenics

Exhibit K 5—L r.67 
The pedigree is thus, in respect of eye-colour—and of other 
characters also which are not here described—clearly Mendelian in 
its manifestations. It shows that the offspring of two very different 
types of human races exhibit the same mode of Mendelian inheritance 
as do the descendants of two contrasted parents of the same race. 
Family 4 (Pedigree Chart, No. K 6) illustrates the same kind of k. 6 
facts and conclusions. In the A Generation a Frenchman, whose eye- 
colour was unknown to my informant, married a full blood Indian 
princess who had Indian brown eyes. There was one daughter only 
{Generation B) by this marriage, and she had Indian brown eyes. She 
married an Irishman, who had red hair, grey eyes, and a freckled com­ 
plexion (Generation B). From this marriage there came six children 
(Generation C). Two of these had “ grey eyes like their father.” 
Three had dark brown eyes of European tint. My informant had 
some doubt as to the European tint of two of these three (Nos. 3 and 
4, C Generation); their eye-colour was very dark brown, and possibly 
it may have been the Indian tint. The remaining member of this 
generation had Indian brown eyes of a very dark shade. 
It may be desirable to state that Families 4 and 5 come from 
different parts of Canada. 
The chief feature of interest in this family is the segregation 
of the grey eye-colour of the Irishman among his offspring. It 
appears in two daughters. From what we know of analogous cases, 
there is little doubt that the gametes of his half-breed Indian wife 
carried the blue or grey factors derived from her French father. 
The appearance of an European brown eye-colour in Generation C, 
No. 6, suggests that the French grandfather had brown eyes, and 
that, therefore, this colour has segregated out among the gametes of 
the half-breed Indian mother. 
Exhibited by Mr. E. Nettleship. 
Congenital Colour-blindness. Pedigree showing unusual T . 
features, viz. : (a) females affected; (b) twins, of whom one is 
affected, the other not; (c) marriage between two unrelated colour­ 
blind stocks. Except that two females are affected the inheritance, 
so far as can be traced, has followed the rule for colour-blindness; 
viz., limitation to males and transmission through unaffected females.
	        

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