The document discusses concepts related to human sex determination and genetics. It provides examples of possible karyotype and medical test results for an individual named Santhi and questions about interpreting these results and their implications. The questions cover topics like determining if Santhi is male or female based on various test results, what a normal human female karyotype would be, the process of meiosis, and issues around requiring gender testing for female athletes.

1. Crossing Over Suma Gondi and Kathryn Addabbo

2. CQ1: Imagine you are a member of the committee assigned to determine whether Santhi is female. Here are possible results of the initial tests (we don’t know the real results): Female genitalia: Yes Breasts and pubic hair: Yes Regular menstrual cycle: Never From this information, you conclude that Santhi is: A: Male B: Female The answer is B, Santhi is female.

3. CQ2: A karyotype was performed on an athlete. Here are the results: From these results, the athlete is: A: Male B: Female The answer is A, because Santhi possesses both an X and Y chromosome.

4. CQ3: So if Santhi is a normal female, her karyotype would be: A: XX B: XY C: YY D: XXY The answer would be A, females possess two X chromosomes.

5. CQ4: Assume that this is one of Santhi’s chromosomes. This chromosome is composed of two chromatids joined by a centromere. A: These chromatids make up a diploid chromosome. B: The cell that contains these sister chromatids must be diploid. C: The sister chromatids were formed by replicating a single chromatid. D: The sister chromatids were joined by fertilization, bringing together a maternal and paternal chromatid. The answer is C, because the chromatids are identical.

6. CQ5: What is true after Meiosis I? A: Four cells have been produced. B: The cells are haploid. C: The DNA will be replicated once more. D: The cells are ready to perform as gametes. E: Each chromosome consists of a single strand of DNA. The answer is B.

7. CQ6: During Meiosis II: A: Homologous chromosomes separate. B: The DNA is replicated. C: Gametes fuse. D: Sister chromatids separate. E: All of the above. The answer is D. Sister chromatids are pulled apart.

8. CQ7: How many possible combinations of maternal chromosomes are possible in a human ovum due to independent assortment during meiosis? A: 23 combinations. B: 46 combinations. C: 23 2 = 529 combinations. D: 2 23 = ~ 8 million combinations. The answer is D. There are many different combinations.

9. CQ8: Could Santhi have an XX karyotype and be male? A: No, an XX individual is always female. B: Yes, this is common. C: Yes, if a male-determining control gene is carried on one of her X chromosomes. The answer is C.

10. CQ9: During crossover, all of the following happen EXCEPT: A: The homologous chromosomes line up in pairs. B: The homologous chromosomes swap pieces with their adjacent partners. C: Crossing over decreases the genetic variability in the gametes. D: Each chromatid is unique after it has crossed over. The answer is C.

11. CQ10: If you were a member of the Asian Games medal committee and Santhi’s karyotype revealed that she is XY and SRY+ , what would you do? A: She has female genitalia, allow her to keep her medal. B: She is genetically male, take her medal away. C: Perform additional tests. Our personal choice is A.

12. CQ11: What do you think about requiring gender testing for female athletes in international competition? A: It should be banned because gender determination is so complex. B: It is necessary to ensure an even playing field. C: It is necessary, but needs to include a large number of genetic tests to ensure fairness. D: It should be required for all athletes, both male and female. Our personal answer is both A and C. Gender determination is very complex, as the possibilities are endless. Yet if testing continues, it should be so fairly.