Karyotyping Activity KEY

In this activity, you will use a computer model to look at chromosomes and prepare a karyotype. You will diagnose patients for abnormalities and learn the correct notation for characterizing karyotypes.

Site 1: www.biology.arizona.edu

Click on Karyotyping under human biology and read the Introduction page:
1. What causes a dark band on the chromosome? __ Giemsa dye _
2. What is a centromere? __________ areas where the two chromatids are joined _____

Patient Histories: *Click on Patient Histories. You will be completing a karyotype for Patient A, B & C

Patient A ( Click on the link to "Complete Patient A's Karyotype" )

*Match the chromosome to its homolog. After all the matches are complete you'll analyze your patient. (Scroll down to view your completed karyotype).

3. What is patient A's history (summarize) _______nearly full term fetus of a 40 year old female______________
4. How many total chromosomes are in your karyotype - count them _47__
The last set of chromosomes is the sex chromosomes, if you have two large chromosomes, your patient is XX (female), one large and one small indicates and XY (male) . What sex chromosomes does your patient have _XX___
Which chromosome set has an extra + __21____
5. What diagnosis would you give this patient (what disease)? ___Down Syndrome______

Patient B - click on the link to go to Patient B and repeat the above process.

6. What is Patient B's history (summarize) _______28 year old male, infertile____________________________
7. How many total chromosomes are in your karyotype - count them ___47____
What sex chromosomes does your patient have _XXY____
Which chromosome set has an extra + __X____
8. Finish the notation for this patient's karyotype : 47 X _XY___
9. What is the diagnosis? ______Klinefelter's Syndrome_______________

Patient C - click on the link to go to Patient C and repeat the above process.

10. What is patient C's history (summarize)? _____died shortly after birth_________________________
11. How many total chromosomes are in your karyotype - count them ___47_____
What sex chromosomes does your patient have __XY____
Which chromosome set has an extra + _13____
12. Write out the correct notation for this karyotype. ___47 XY +13____
13. What is the diagnosis? ____Trisomy 13 Syndrome_______________

Site 2: Genetic Science Learning Center ( http://learn.genetics.utah.edu/ )

Go to "heredity and traits" --> "How Do Scientists Read Chromosomes"
(Find the answers to the following questions in this area. Browse all sections)

1. What are the three key features used to read chromosomes?
____size___________
____banding pattern_______________
____centromere position_____________

2. Sketch or describe: metacentric, submetacentric, acrocentric

metacentric - centromere is near the center
submetacentric - one arm is much shorter than the other
acrocentric - centromere lies at one end

3. Got to Make a Karyotype - Try it yourself - Create your own karyotype - turning on hints is okay.
Check this box when your karyotype is complete
What did you find difficult about matching the chromosomes? __answers vary, chromsomes can be difficult to match________

4. Go to - Using Karyotypes to Predict Genetic Disorders
What is trisomy? ______extra chromosome, individual has 3 instead of 2 for a group______________
What is monosomy? ____missing chromosome, only one in a pair is present____________________
What is a terminal deletion? ___a chromosome is missing a piece, usually the tip________________

5. For each of the Disorders, describe the chromosome abnormality and the symptoms.

Cri Du Chat - name of this syndrome is French for "cry of the cat," caused by a delection of chromosome #5

Turner Syndrome - missing or incomplete X chromosome, girls with this disorder are shorter than normal, and may fail to start puberty when they should.

Klinefelter Syndrome -  males who have Klinefelter syndrome have an extra X chromosome (XXY), males have less muscular body, and grow very little facial or body hair, also infertile

Williams Syndrome - missing genetic material from chromosome 7, causes problems with the circulatory system and heart defects.

 

Extra Credit - http://bluehawk.monmouth.edu/~bio/karyotypes.htm

Pick from the list of abnormal karyotypes and arrange the chromosomes in a karyotype. Use the "print screen" button to copy your finished karyotype onto a word processing document. For "Diagnosis" write the chromosome set that has the abnormality, and what type of abnormality it is. Print this page out and turn it in.