In humans, the recessive genes for color blindness and night blindness (“night blindness”) are linked to the X chromosome and are located
In humans, the recessive genes for color blindness and night blindness (“night blindness”) are linked to the X chromosome and are located at a distance of 40 morganids from each other. The webbing of the legs is inherited as a recessive trait linked to the Y chromosome. Brown eye color is the dominant autosomal trait, blue eye color is autosomal recessive. What kind of children and in what ratio can be expected from a marriage of a trigheterozygous brown-eyed woman and a heterozygous brown-eyed man with normal vision and webbed legs if:
1) in a woman, the genes for color blindness and night blindness are in the cis position (there is no crossing over);
2) in a woman, the genes for color blindness and night blindness are in a trans position (there is no crossing over);
3) in a woman, the genes for color blindness and night blindness are in the cis position (crossing over occurs);
4) are the genes for color blindness and night blindness in a woman in a trans position (crossing over occurs)?
1) From marriage of a heterozygous brown-eyed woman for three signs and a heterozygous brown-eyed man with normal vision and webbed legs, if a woman has genes for color blindness and night blindness in the cis position (there is no crossing over), brown-eyed girls with normal vision without webbed legs can be expected. blue-eyed girls with normal vision without webbed legs, brown-eyed boys with normal vision and webbed legs, brown-eyed color-blind boys with night blindness and webbed legs, blue-eyed boys with normal vision and webbed legs, blue-eyed boys with color blindness with night blindness and webbed legs 6: 2: 3: 3: 1: 1;
2) from marriage of a brown-eyed woman heterozygous for three signs and a heterozygous brown-eyed man with normal vision and webbed legs, if a woman has genes for color blindness and night blindness in the trans position (crossing over is absent), brown-eyed girls with normal vision without webbed legs can be expected. blue-eyed girls with normal vision without webbed feet, brown-eyed boys with normal color vision, night blindness and webbed feet, brown-eyed color-blind boys with normal night vision and webbed feet, blue-eyed boys with normal color vision, night blindness and webbed feet – color blind with normal night vision and webbed feet in a ratio of 6: 2: 3: 3: 1: 1;
3) from marriage of a heterozygous brown-eyed woman for three signs and a heterozygous brown-eyed man with normal vision and webbed legs, if a woman has genes for color blindness and night blindness in the cis position (crossing over occurs), 37.5% of brown-eyed girls with normal vision can be expected without webbed legs, 12.5% blue-eyed girls with normal vision without webbed legs, 11.25% brown-eyed boys with normal vision and webbed legs, 11.25% brown-eyed color-blind boys with night blindness and webbed legs, 7.5% brown-eyed color-blind boys with normal night vision and webbed feet, 7.5% of brown-eyed boys with normal color vision, night blindness and webbed feet, 3.75% of blue-eyed boys with normal vision and webbed feet, 3.75% of blue-eyed boys with night blindness and webbed feet, 2.5% of blue-eyed color-blind boys with normal night vision and webbed feet, 2.5 % of blue-eyed boys with normal color vision, night blindness and webbed feet;
4) from marriage of a heterozygous brown-eyed woman for three signs and a heterozygous brown-eyed man with normal vision and webbed legs, if a woman’s genes for color blindness and night blindness are in a trans position (crossing over occurs), 37.5% of brown-eyed girls with normal vision can be expected without webbed legs, 12.5% blue-eyed girls with normal vision without webbed legs, 7.5% brown-eyed boys with normal vision and webbed legs, 7.5% brown-eyed color-blind boys with night blindness and webbed legs, 11.25% brown-eyed color-blind boys with normal night vision and webbed feet, 11.25% of brown-eyed boys with normal color vision, night blindness and webbed feet, 2.5% of blue-eyed boys with normal vision and webbed feet, 2.5% of blue-eyed boys with night blindness and webbed feet, 3.75% of blue-eyed color-blind boys with normal night vision and webbed feet, 3.75 % blue-eyed boys with normal color vision, night blindness, and webbed feet.
