Concept explainers
A human female with Turner syndrome (47, X) also expresses the X-linked trait hemophilia, as did her father. Which of her parents underwent nondisjunction during meiosis, giving rise to the gamete responsible for the syndrome?
To determine: The parent whose genome has undergone nondisjunction during meiosis that resulted in a human female with Turner syndrome (47, X) along with X-linked trait hemophilia.
Introduction: Turner syndrome is a condition in which female which is born have only 45 chromosomes and the missing chromosome is an X-chromosome. Since the X chromosome is missing the various proteins which are coded by the X-chromosome are affected. Thy symptoms of turner syndrome include short stature, reproductive sterility, visual impairments, nonverbal learning disability and various other conditions.
Explanation of Solution
Aneuploidy is a condition in which a person loses only one chromosome but the other complementary chromosome is present. In non-disjunction the chromosomes are unable to separate the linked homologs or chromatids during mitosis or meiosis.
Hemophilia is an X-linked trait and since the father and daughter both are suffering from this condition, this implies that the X chromosome from the father was inherited to the girl. So, it can be concluded that the Turner’s syndrome arises due to non-disjunction observed in the mother, which prevents the entry of X-chromosome from the mother resulting in only a single X-chromosome that has been inherited from the father.
The Turner syndrome is a result of nondisjunction of the chromosomes during the formation of gamete in mother.
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