. The physical basis of heredity . h gives red eyes is indicated byW. The X-chromosome that carries the gene for whiteeyes is indicated by tv. The rod with a bent end standsfor the F-chromosome. The Fj daughters contain one of each kind of X-chro-mosome. The Fi sons only one kind. The recom-binations that give the Fo results are shown in the middleof the lower part of the diagram. Half of the femalesare seen to be homozygous for the wild-type gene (W).They should never transmit white eyes, and they do other half of the females are heterozygous (W«/), andif mated to a white-eyed male sh
. The physical basis of heredity . h gives red eyes is indicated byW. The X-chromosome that carries the gene for whiteeyes is indicated by tv. The rod with a bent end standsfor the F-chromosome. The Fj daughters contain one of each kind of X-chro-mosome. The Fi sons only one kind. The recom-binations that give the Fo results are shown in the middleof the lower part of the diagram. Half of the femalesare seen to be homozygous for the wild-type gene (W).They should never transmit white eyes, and they do other half of the females are heterozygous (W«/), andif mated to a white-eyed male should give 50 per males and females, and 50 per cent, white-eyedmales and females. This they do. The red Fo sons (IF)should never transmit white eyes, nor the white-eyed sons(w) transmit red eyes. These relations are also knownto hold. The reciprocal cross (Fig. 70), viz., a white-eyedfemale (ww) to a red-eyed male (IF) gives red-eyeddaughters (ivW) and white-eyed sons (w). If these Fjs 168 PHYSICAL BASIS OF HEREDITY. Fig. 69.—Cross between white-eyed male and a red-eyed female of the vinegar fly. SEX-CHROMOSOMES AND INHERITANCE 169
Size: 1318px × 1897px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectheredit, bookyear1919
