Correct option is C
The correct answer is option (3): Non-disjunction event in the mother.
Explanation:
Turner’s Syndrome (45,X) is a chromosomal disorder where a female has only one X chromosome instead of the usual two. This condition typically occurs due to a non-disjunction event during meiosis in the mother, leading to the loss of one of the X chromosomes.
Since the father is color blind, he must have the X-linked recessive allele for color blindness. He will pass on his X chromosome to his daughter, making her color blind, as females inherit an X chromosome from both parents.
Non-disjunction refers to the failure of chromosomes to separate properly during meiosis, leading to an incorrect number of chromosomes in the gametes. In this case, the mother’s egg likely contributed only one X chromosome to the daughter (due to a non-disjunction event), leading to the formation of a daughter with Turner's syndrome (45,X).
Why other options are incorrect:
Option (1) Translocation event in the father: Translocation events involve the exchange of chromosomal segments between non-homologous chromosomes. While translocations can lead to genetic disorders, they are not typically associated with Turner’s syndrome, which results from missing a chromosome rather than an exchange between chromosomes.
Option (2) Translocation event in the mother: Translocations in the mother could cause genetic disorders, but Turner’s syndrome is typically caused by a missing X chromosome, not by a translocation.
Option (4) Non-disjunction event in the father: Non-disjunction events during father’s meiosis are typically associated with conditions like Klinefelter syndrome (47,XXY) or other disorders related to the sex chromosomes. However, Turner's syndrome is caused by a missing X chromosome in the female, which generally occurs due to non-disjunction in the mother.
Additional Information:
Color blindness is an X-linked recessive trait, so the father will pass his X chromosome with the color blindness allele to his daughter. Since the daughter inherits this X chromosome from her father and no second X chromosome from her mother (because of the non-disjunction event), she will be color blind and will also have Turner's syndrome (45,X).
