Caroline Purser teaches accelerated bi- How-To- Do- It ology at Moon Valley High, 3625 West Cactus Rd., Phoenix, AZ 85029 where she has taught since 1965. She received her B.S. in Physical Education and Science in 1962 from Oklahoma State Univ. and her KaryotypeSuccess Rate Increases With M.S. in Secondary Science from Arizona State Univ. in 1972. Purser is a member of NABT, Arizona/Nevada Academy of Stylized Science and Delta Kappa Gamma. Among the NSF grants she has received, the most recent was for an honors workshop in ge- netics and bioethics at Ball State Univ. in CarolinePurser 1985.

Students enjoy the cut and paste ac- mosomes with the template and then lies with a diploid set of chromosomes Downloaded from http://online.ucpress.edu/abt/article-pdf/49/6/360/42963/4448549.pdf by guest on 27 September 2021 tivity of preparing a hypothetical glue the pairs in correct as shown in Figure 4. karyotypewhen they are successful in order by length, on the determining the correctdisorder. form (Figure3). When they have com- First, students should receive back- pleted the karyotype they should read References ground information on the needs for about the disorders (Appendix 1) and Nagle J.J. (1984). and humanaffairs. this type procedure, along with an ex- determine the anomaly, as evidenced St. Louis, MO: Times Mirror/Mosby, planation of , the cul- by the karyotype they have prepared. College Publishing. turing of the cells and the process of The value sheet (Appendix2) can be Nyhan, W.L. (1983).Clinical symposia: Cyto- karyotype preparation. used in a bioethical decision making genetic diseases. Vol. 35(1). New York: The students then get a template process. Wise teachers will, of course, CIBAPharmaceutical. Singer, S. (1978).Human genetics. San Fran- (Figure 1) and a hypothetical set of be sensitive to the standards of the cisco: W.H. Freeman & Co. nine chromosomes shown in Figure2. community in which they teach. Winchester, A.M. & Mertens, T. (1983). The students' task is to match the Teachers can prepare additional Humangenetics. Columbus, OH: Charles banding patterns of their smear chro- chromosome smears of other anoma- MerrillPublishing.

Appendix 1. Information on ChromosomeDisorders. makes speech difficult and mental EdwardsSyndrome retardation. Individuals with this Cri-du-chat syndrome have a high incidence of This syndrome ( 18) pro- respiratoryinfections, heart defects duces severe mental retardation Babies with the cry of the cat and . The average risk of and a highly characteristicpattern syndrome have a cry which sounds having a child with trisomy 21 is of malformationssuch as elongated like that of a cat in distress; because 1/750 live births. Mothers in their skull, a very narrow pelvis, rocker the 's larynx is improperly early twenties have a risk of 1/1,500 bottom feet and a grasping of the developed. The cause of this condi- and women over 35 have a risk two central fingers by the thumb tion is a of about half of factor of 1/70, which jumps to 1/25 and little finger. In addition, the the short arm of chromosome for women 45 or older. ears are often low set and the number five. Cri-du-chatbabies are mouth and teeth are small. Nearly severely mentally retarded and Karyotype:47 XYor 47 XXwith 3 of all babies born with this condition have a small cranium. The inci- die in early infancy. The frequency dence of this syndrome is 1/100,000 of this syndrome is 1/5,000 live live births. births. Karyotype:46 XXor 46 XYwith one 14-21 translocation. Rather than Karyotype:47 XXor 47 XYwith 3 of chromosome #5 upper arm dele- trisomy 21, this form of Down syn- tion. drome has a chromosone count of 46, but an extrachromosome 21 has PatauSyndrome Down Syndrome become attached to chromosome 14. of this This syndrome (trisomy 13) Trisomy 21, one of the most anomaly are identical to those asso- causes severely abnormal cerebral common causes of mental retarda- ciated with trisomy 21. The carrier functions and virtually always tion is due to an extra chromosome of the translocation is normal but leads to death in early infancy. This 21. This results in a number of has a 50 percent chance of passing baby has very pronounced clefts of characteristic features, such as it on. the lip and palate, broad nose, short stature, broad hands, stubby small cranium and nonfunctional fingers and toes, a wide rounded Karyotype:46 XX or 46 XY, translo- eyes. Heart defects and severe face, a large protruding tongue that cation 14/21 mental retardationare also part of

360 THE AMERICAN BIOLOGY TEACHER, VOLUME 49, NO. 6, SEPTEMBER 1987 the clinical picture. The frequency Appendix 2. Student is 1/15,000. Value Sheet. Karyotype:47 XX or 47 XYwith 3 of . The student value sheet will make it write a paragraph supporting this de- necessary for the students to stop and cision. This statement will require stu- analyze the situation provided by the dents to express their personal values. TurnerSyndrome hypothetical karyotype. It will require If they are opposed to abortion in all them to list the anomaly, cause and cases, they should write a paragraph (XO) This condition happens symptoms, and in the process, they that supports their values. when an X-carrying sperm fer- may develop an opinion. The student tilizes an ovum that lacks an X, or value sheet then allows them to ex- Name of anomaly when a sperm lacking an X or Y press this opinion on a scale of 1-5 and Cause of anomaly chromosome fertilizes an X-bearing support their rationalein a paragraph. Majorsymptoms egg. These girls appear to be normal before puberty, although Directions: Each student will list a they are shorter and have a chunky hypothetical anomaly, its cause, Probabilityof occurrence build. At birth, the distinguishable symptoms and probability of occur- Likelihood of abortion: characteristicsinclude a thick fold rence, then rank the likelihood of 1 2 3 4 5 of skin on either side of the neck. aborting the fetus on a scale of 1-5. 1 never always Downloaded from http://online.ucpress.edu/abt/article-pdf/49/6/360/42963/4448549.pdf by guest on 27 September 2021 At sexual maturity, the secondary representing never, and 5 repre- Reasons for your decision: sex characteristicsdo not develop senting always. The students will then and no ova are produced. There also is no menstruation or breast development. The frequency is 1/2,500 live female births.

Karyotype:45 X ( X)

KlinefelterSyndrome (XXY) A condition occuring in 1/1,000 male live births. Character- istics associated with this condition are tall stature, small testicles, and sterility. Most men with this syn- drome appear normal in other 2 3 4 5 X ways.

Karyotype:47 XXY

Jacobs (XYY)A chromosome aberration which is caused by 6 ~8 210 11 1' of the during the second phase of . Occur- rence is 1/1,000 live male births. Men with this anomaly are tall and have low mental ability.

Karyotype:47 XYY 13 14 15 16 17 18

TripleX (XXX or superfemale) Occurs at a X pZ t 0I frequency of 1/1,000 female live 21 22 Y births. No specific abnormalities 19 20 are associated with this condition. The vast majority of women who have this condition are normal Figure 1. Template or Guide to Chromosome Banding. Use this diagram as a model to mentally and physically and are determining the chromosome identity. This can be done by matchingthe banding patterns. fertile. Please note that the smear chromosomes have a reduced size, so the student must match bands instead of size. A normalkaryotype will have two of each chromosome #1-22 and the Karyotype:47 XXX male will have an X and a Y, and the female two X chromosomes.

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Q. E. D. COMPUTING EDUCATIONALSOFTWARE P.O.BOX5037 KENT,WA 98064-5037 Figure 4. Using these two sets of chromo- | E i" somes, the instructorcan cut and paste and prepare additional hypothetical chromo- some smears. However, instructors need to remember that each set has an X and a SCIENCE 9 2 I s 9 x Y, so they need to delete or add what they want to appear in the smear. They must CROSSWORDS also remember to add extra chromosomes for or take away chromosomes BIOLOGY EU ~~~~~m ~~~j~for deletions. * 7 3 130 33 12 Creates Concept Confidence w ~~~~~~~~~~~~~~~~~~~~~~MakesLearningExciting and Fun! ~~* ~~~{~ ~ ~ 2e LEAF STRUCTURE AND FUNCTION

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STYLIZED CHROMOSOMES 363