Genetics in ophthalmology / Arnold Sorsby.

  • Sorsby, Arnold, 1900-1980.
Date:
1951
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Genetics in ophthalmology / Arnold Sorsby. Source: Wellcome Collection.

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    ILLUSTRATIVE PEDIGREES { f f Г пр, ШП Ш1 ÍITl lAljUlU ri raiím Fig. 29.—Recessive sex-linkage: (1) A pedigree of red-green blindness. {After W. D. Homer (1876) quoted in Treasury of Human Inheritance, 1933, Ed. by K. Pearson, Vol. 2 {by Julia Bell), Fig. 420. London; Cambridge University Press.) Recessive Sex-linkage The theoretical possibiHties with a recessive gene on the non-homologous part of the X chromosome discussed on page 77 may be summarized in the following scheme, in which a heavy X stands for a chromosome which carries a pathogenic gene. (A) Affected father (XY) (1) ' XY XX (3) (2) XX XX XY XY XY XX XX XX XY XY XY XX XX XX XY XY Affected father and normal mother Daughters: all carriers Sons: all normal Affected father and carrier mother Daughters: 50% affected 50% carriers Sons: 50% affected 50% normal Affected father and affected mother Daughters: all affected Sons: all affected (B) Normal father (XY) (4) XY XX (5) XX XX XY XY XY XX Normal father and carrier mother Daughters: 50% carriers 50% normal Sons: 50% affected 50% normal Normal father and affected mother I I I I Daughters: all carriers XX XX XY XY Sons: all affected 41