In humans, the brown eye gene dominates the blue eye color (A), and the color blind gene is recessive (color blind – d) and linked to the X chromosome. A brown-eyed woman with normal eyesight, whose father had blue eyes and suffered from color blindness, marries a blue-eyed man with normal eyesight. Make a scheme for solving the problem. Determine the genotypes of parents and possible offspring, the likelihood of birth in this family of children – color blind with brown eyes and their gender.
1) the mother genotype is AaXDXd (gametes: AXD, aXD, AXd, aXd), the father’s genotype is aaXDY (gametes: aXD, aY);
2) genotypes of children: girls – AaXDXD, aaXDXD, AaXDXd, aaXDXd, boys – AaXDY, aaXDY, AaXdY, aaXdY;
3) the probability of giving birth to color blind children with brown eyes: 12.5% of AaXdY are boys.
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