Heredity and sex . o Chn 660 o 6 Fig. 116. — Pedigree of Ichthyosis from Bramwell. (After Davenport.) vision. The sons will all be normal, since theyget the X chromosomes from their mother. In thenext generation, as shown in the diagram (third hne),four classes arise, normal females, hybrid females, normalmales, and hsemophilious males. Color blindness fol-lows the same scheme, as the above diagrams illustrate(Figs. 114 and 115). In the first diagram the color-blind male is represented by a black eye; the normalfemale by an eye without color. The offspring from SPECIAL CASES OF SEX-INHERITANCE
Heredity and sex . o Chn 660 o 6 Fig. 116. — Pedigree of Ichthyosis from Bramwell. (After Davenport.) vision. The sons will all be normal, since theyget the X chromosomes from their mother. In thenext generation, as shown in the diagram (third hne),four classes arise, normal females, hybrid females, normalmales, and hsemophilious males. Color blindness fol-lows the same scheme, as the above diagrams illustrate(Figs. 114 and 115). In the first diagram the color-blind male is represented by a black eye; the normalfemale by an eye without color. The offspring from SPECIAL CASES OF SEX-INHERITANCE 243. 244 HEREDITY AND SEX two such individuals are normal, but the color blindnessreappears in one-fourth of the grandchildren, and inthese only in the males. The reverse mating is shownin the next diagram in which the female is will have color-blind sons and normal daughters(criss-cross inheritance), and all four kinds of grand-children. Other cases in man that are said to show sex-linkedinheritance are atrophy of the optic nerve, multiple cTT^ *P iSiiiiiliitiiiii
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Keywords: ., boo, bookcentury1900, bookdecade1910, booksubjectsex, bookyear1913
