sex verification(new) - Sex Verification Testing of...

Unformatted text preview: Sex Verification Testing of Athletes Student Worksheet Click & Learn INTRODUCTION This handout complements the Click & Learn “Sex Verification Testing of Athletes.” LESSON PROCEDURE As you proceed through the interactive, follow the instructions and answer the questions in the spaces provided. INTRODUCTION Select the “Introduction” tab and watch the opening video. After watching the video, scroll down and read the text. As you read, click on the underlined terms to learn more about them. When you have finished, answer questions 1-3 below. 1. What evidence provided supports the claim that “A high level of testosterone provides an unfair advantage in women’s athletics”? Is this adequate evidence? Explain your answer. Testosterone helps your body perform better. Men have high tetstosterone naturally which helps their athletic performence. Women think it is unfair that some women who have higher testosterone can run faster or are stornger than they are. Top male athletes outcompete top female athletes by 10%. 2. Click on the term “biological sex.” Describe how biological sex and gender differ from each other. Biological sex is defined by an individual's combo of hormone levels, chromosomes, sex characteristics, and internal and external reproductive anatomy. 3. Are sex verification tests of athletes used to determine biological sex or gender? Explain why you selected sex or gender. Sex verification tests are used to determine biological sex not gender. I selected sex because these tests are done to make sure that only athletes that are biologically the gender they are competing against could compete. Males used to pretend to be females to try and win the olympics. HUMAN DEVELOPMENT Click the “Human Development” tab. As you navigate through this section, use the information to answer questions 4-20. 4. Rewrite the following statement to be correct regarding human chromosomes: “All chromosomes are autosomes, and some autosomes are allosomes.” All chromosomes are autosomes except the X and Y chromosomes. In females the two allosomes are XX and in males they are XY. Genetics Published December 2018 Page 1 of 8 Click & Learn Student Worksheet Sex Verification Testing of Athletes 5. What does the presence of a Barr body indicate? It indicates that the person has more than one X chromosome. 6. Regarding the SRY gene … a. What does SRY stand for? SRY stands for sex determining region Y gene. b. On which chromosome is the SRY gene normally found? The SRY gene is located on the Y chromosome. c. What is the function of the SRY gene? The gene affects a key control point for the differentiation of the immature gonads into the testes. 7. Think about it. If an embryo made testosterone normally but did not have testosterone receptors in any of its cells, would the embryo develop female reproductive structures, male reproductive structures, or no reproductive structures? Explain your answer. The embryo would develop female reproductive structures because they produced testosterone normally. Although the testosterone didn't have anywhere to go to because ther are no receptors. 8. Examine the graph showing blood testosterone levels in elite male and female athletes. Fill in the table below to show the range and mode (highest frequency) of testosterone concentration for females and males in this study. Females Range Low 1 High nmol/L 98 nmol/L nmol/L Males 1 nmol/L 35 nmol/L nmol/L Sex Mode 9. Based on the data in the graph of blood testosterone levels in elite male and female athletes, is there a testosterone concentration that can reliably divide females from males? Explain your answer. No, it isn't that reliable. They did two different graphs and both of them had different percentages of females who have higher testosterone levels than others. On a average, male athletes have higher testosterone concentrations about 10 times those of the female athletes. Genetics Published December 2018 Page 2 of 8 Sex Verification Testing of Athletes Click & Learn Student Worksheet 10. Secondary sex characteristics arise during puberty. What causes these developmental changes? It is caused by the surge in androgens and estrogens released during puberty. 11. List two examples of secondary sex characteristics in females and two in males. In males, they could include facial hair and a deeper voice. In females, they could include enlarged breasts and an increase in body fat. 12. Are there secondary sex characteristics that could be the basis of a reliable sex determination test? Explain your answer. No, not reliable because some females naturally have a deep voice or facial hair. Some males could have an increse in body fat, which would then give him breasts. You cannot judge the gender by someones secondary sex characteristics, it just isn't reliable. 13. Regarding DSDs … a. What does the abbreviation DSD stand for? DSD stands for differences in sexual development. or disorders of sex development. b. How common are DSDs? 1 in 100 births show differences from typical development. Answer the following questions using the table of DSDs. 14. CYP21A2 gene mutations a. By what mechanism can a mutation in CYP21A2 change testosterone levels? b. What changes in phenotype are typical in people with a CYP21A2 mutation? 15. SRY gene mutations a. How can an error in chromosome segregation during meiosis affect inheritance of the SRY gene? Genetics Published December 2018 Page 3 of 8 Sex Verification Testing of Athletes Click & Learn Student Worksheet b. What is the effect of a nonfunctional SRY gene on the development of primary sex characteristics? c. Which sex is typically assigned at birth to an individual with a mutation that results in a nonfunctional SRY gene? 16. XO a. How can an error in chromosome segregation result in Turner syndrome? b. Can an individual with Turner syndrome have biological children? 17. AR gene mutation a. Which phenotypes may arise in an individual with a mutation in the AR gene? b. In humans, the AR gene is located on the X chromosome. If a person who is XY has a complete deletion of the AR gene, do you think giving them testosterone injections during puberty would cause an increase in expression of male secondary sex characteristics compared to not receiving injections? Explain your answer. 18. XXY a. Which of the following terms describes the process of homologous chromosomes failing to separate correctly during meiosis? C. Ametaphasia A. Chromatid adhesion syndrome D. Anti-anaphase B. Nondisjunction b. If a person with Klinefelter’s syndrome wanted to look more like an average male, what medical treatment could help accomplish this? Genetics Published December 2018 Page 4 of 8 Sex Verification Testing of Athletes Click & Learn Student Worksheet 19. SRD5A2 gene mutation A mutation of the SRD5A2 gene causes a deficiency in the enzyme 5-alpha reductase. Describe how this affects … a. embryonic development b. external reproductive anatomy at birth c. secondary sex characteristics at puberty 20. AMH or AMHR2 gene mutations a. What typically happens to the Müllerian ducts in females during development? b. What typically happens to the Müllerian ducts in males during development? c. Which internal reproductive structures would a person with a mutation in the AMH or AMHR2 gene have? Genetics Published December 2018 Page 5 of 8 Sex Verification Testing of Athletes Click & Learn Student Worksheet CASE STUDIES Click the “Case Studies” tab, read about the two athletes and the history of sex verification tests, and then use the information to answer questions 21-22. 21. Click the "Sprinter" tab. a. Which four tests have historically been performed to determine an athlete’s biological sex? b. What is a genotype that would explain the sprinter’s phenotype? Explain. 22. Click the "Swimmer" tab. Under current regulations, would the swimmer be allowed to compete? Explain. EXTENSION ACTIVITY DSD TABLE The table on the following page provides additional information on the DSDs shown at the bottom of the Human Development tab. Complete the table to indicate whether a “sex verification test” of a person with each listed DSD would show Barr bodies or the SRY gene, whether their testosterone level would be low (typical of a female) or high (typical of a male), and whether they are likely to menstruate or be fertile (able to have biological children without in vitro fertilization or other medical interventions). Genetics Published December 2018 Page 6 of 8 Chromosomes Genetic mutation Syndrome Internal reproductive anatomy External genitalia Secondary sex characteristics Sex typically assigned at birth 46,XX None None Female Female Female Female 46,XX CYP21A2 mutation or deletion Congenital adrenal hyperplasia Female Ambiguous Male but reduced Female 46,XY SRY mutation or deletion Swyer syndrome Female but nonfunctional ovaries Female Absent or female, but reduced Female 45,X Complete or partial loss of X chromosome Turner syndrome Female but absent or nonfunctional ovaries Female Absent or female, but reduced Female 46,XY Androgen receptor (AR) deletion Complete androgen insensitivity syndrome Shortened vaginal canal and testes, no fallopian tubes or uterus. Female Female Female 47,XXY Extra X chromosome Klinefelter syndrome Male Male Male but reduced. Breast growth may occur Male 46,XX SRY gene translocation to X XX male syndrome Male Male but small testes Male but reduced Male 46,XY SRD5A2 mutation or deletion 5-alpha reductase deficiency Male Female or ambiguous Male Female No 46,XY Mutation or deletion of the genes for AMH or AMH receptor (AMHR2) Persistent Müllerian duct syndrome Male reproductive organs plus uterus and fallopian tubes Male, but one or both testes may be undescended Male Male No 46,XY None None Male Male genitalia Male Male Genetics Barr body (Y/N) SRY gene (Y/N) Testosterone (Low/High) Menstruation (Y/N) Fertile (Y/N) Published December 2018 Page 7 of 8 Sex Verification Testing of Athletes Click & Learn Student Worksheet EXTENSION ACTIVITY Four factors are considered when determining a person’s biological sex: 1) chromosomes, 2) hormones, 3) primary sex characteristics that are features essential for sexual reproduction (internal reproductive structures and external genitalia), and 4) secondary sex characteristics, features that typically appear during puberty and are different between the sexes, but are not directly involved in reproduction (for example, females typically have enlarged breasts and widened hips; and males typically have increased facial and body hair, increased muscle mass, and a larger Adam’s apple). Given that the top male athletes outcompete the top female athletes by about 10% in most sports, provide a justification for how each of these four factors is or is not likely to contribute to performance differences between sexes. Factor that helps determine biological sex Likely to affect athletic Justification performance? (Y/N) Chromosomes Hormones Primary sex characteristics Secondary sex characteristics Genetics Published December 2018 Page 8 of 8 ...
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