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Certain traits, such as color blindness, are determined by an X-linked recessive gene. A couple in which both have normal vision have a color-blind son. The probability of this couple having a daughter who is a carrier is

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Answer:

A daughter can become a carrier in one of two ways – she can acquire the ‘gene’ from a carrier mother or from a color blind father.

Step-by-step explanation:

If a woman has only one color blind ‘gene’ she is known as a ‘carrier’ but she won’t be color blind. When she has a child she will give one of her X chromosomes to the child. If she gives the X chromosome with the color blindness ‘gene’ to her son he will be color blind, but if he receives the X chromosome which doesn’t carry the color blindness ‘gene’, he won’t be color blind.

A color blind boy can’t receive a color blind ‘gene’ from his father, even if his father is color blind, because his father can only pass an X chromosome to his daughters.

A color blind daughter therefore must have a father who is color blind and a mother who is a carrier (who has also passed the color blindness ‘gene’ to her daughter). If her father is not color blind, a ‘carrier’ daughter won’t be color blind. A daughter can become a carrier in one of two ways – she can acquire the ‘gene’ from a carrier mother or from a color blind father.

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