Medical Genetics Homework-2.doc

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1、） Medical Genetics Homework-2Student Number: Name： . Pick the best answer and write in the corresponding blanks: 12345671. Which of the following chromosomal aberrations can be of either sex: A. XYY B. XXY C. trisomy 21 D. monosomic X 2. Which of the following techniques was mostly used to detect a

2、trisomy? A. RFLP B. Southern blotting C.FISH D. PCR-SSCP 3. If an eneuploid with a karyotype that is 2N +1 has 9 chromosomes, what is the normal haploid number of this species?A. 10 B. 9 C. 8 D. 5 E. 4 4. Each of the following chromosome abnormalities involves a 20 megabase region of the long arm of

3、 chromosome 5 (5q). Which abnormality is most likely to cause severe disease?A. Deletion of the region B. Duplication of the regionC. A balanced translocation involving the region (i.e., in the translocation carrier)D. Pericentric inversion 5. Which of the following is not true of Fragile X syndrome

4、? A. It is associated with methylation B. It can be diagnosed using a karyotypeC. It is caused by a trinucleotide repeat expansion D. It displays nearly 100% penetrance 6. Which of the following could produce an XY female? A. Deletion of the Sry gene B. Point mutation in the Sry geneC. Translocation

5、 of the Sry gene to the X chromosome during meiosis in the fatherD. All of the above 7. A cytogenetic term that refers to a mitotic cell that contains twice the normal number of chromosomes is: A. diploid B. polyploid C. endoreduplicated D. tetraploid. Answer questions1. How many different kind of g

6、ametes can an XYY male form, and what are they? Answer: 2. Why do chromosomal abnormalities involving the sex chromosomes usually have less severe phenotypic effects than those involving the autosomes? Answer: 3. What is the parental origin of the extra chromosome in the Down syndrome child below,an

7、d was the error in meiosisor meiosis?Answer: 4. A male with the green form of color blindness and a normal female have a child with Turner syndrome who has normal color vision. In which parent did the nondisjunction occur? Answer: 5. A normal woman with 45 chromosomes has a child with Down syndrome, this child has 46 chromosomes. How would you explain this? Answer: