PROCEDURE:

1. Obtain a set of chromosomes
2. Match the chromosomes with their homologous mate.  One chromosome of each pair is numbered,  as you match your chromosomes number the homologous pairs.  You need to be very systematic.   The number one chromosome is the largest.  Its corresponding mate should be of the same size, with the same banding pattern, and have the same centromere location.
3. Determine the karyotype abnormality using the Chromosome Analysis Key that is below.  Keep in mind there might be some slight variations.  The key below will help guide you.
4. Research your abnormality using the resources available.  A photograph of a real karyotype for the disorder is in the computer database.
5. Locate examples of the five types of chromosome abnormalities  using the computer or karyotypes from other lab groups in the room.

• 1A    46 chromosomes in karyotype...................................................... GO TO STATEMENT 3
• 1B    Not 46 chromosomes in karyotype............................................... GO TO STATEMENT 2

• 2A    47 chromosomes in karyotype (3 of one chromosome)............. Trisomy condition
• 2B    One chromosome missing from pair............................................. Monosomy condition

• 3A   All chromosomes are matched with its homologue without obvious missing pieces or additions -  .....................................................................................................................Possible Normal individual
• 3B    Homologous pairs are not identical in size................................... GO TO STATEMENT 4

• 4A   There are additions pieces attached to a chromosome.............. Translocation

4B   There are missing pieces in a chromosome.................................. Deletion

1. Procedure for karyotyping
2. Different karyotype techniques
3. Classification of chromosomes using size and centromere placement
4. Types of Chromosomal mutations
a.) trisomy - an extra chromosome is present. Duplication of a portion of a chromosome may attach to a chromosome or remain as a separate
fragment.
b.) monosomy - a chromosome is missing
c.) translocation is the result of chromosomal breakage but the broken segment transfers itself to a broken segment of another chromosome. There are both balanced and unbalanced translocations.
d.) deletion - Deletion occurs when a chromosome breaks and a portion of the chromosome is lost.
e.)  inversion - a section of the chromosome is inverted (reversed) on the same chromosome

1. Normal female 46, XX karyotype
2. Normal male 46, XY karyotype

1. Trisomy 13 (47, XX, +13) karyotype
2. Trisomy 16 with single X chromosome (46, X, +16) karyotype
3. Trisomy 18 (47, XY, +18) karyotype
4. Trisomy 21 (47, XY, +21) karyotype
5. Trisomy XXX, triple XXX (47,XXX) karyotype
6. Klinefelter's syndrome, trisomy karyotype (47, XXY)
7. 49,XXXXY,  Variation of Klinefelter's syndrome
8. Jacobs Syndrome Trisomy XYY

1. Monosomy X, or Turner's syndrome (45, X) karyotype

1. Robertsonian translocation, 14 to 13, balanced karyotype
2. Down Syndrome 14-21 Translocation
3. Philadelphia chromosome (9:22 translocation) karyotype with chronic myelogenous leukemia

1. Wolf-Hirschhorn (4p- deletion) syndrome karyotype
2. Cri-du-chat 46 XX or 46 XY with one chromosome #5 upper arm deletion
3. Jacobsen's Syndrome (11q Deletion, or 11q-)
4. DiGeorge Syndrome 22 deletion

1. Inversion of chromosome 16  

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1. Explain what the word cytogenetics means.
2. Briefly discuss the chromosome abnormality in the karyotype.  Be sure to include the type of abnormality,  the total number of chromosomes in the karyotype,   the specific chromosome involved, the gender of karyotype, and the reason for the gender.
3. Using your knowledge of meiosis discuss how the chromosome abnormality could have occurred.
4. After comparing disorders, which of the chromosome disorders seems to be the most damaging? Least?   Explain giving an example.  Why do you think that there was only one monosomy example?
5. Karyotyping can be used as a prenatal screening tool.  Is a baby guaranteed from genetic disorders if the chromosome configuration appears normal?  Explain.
 

TEACHER NOTES:
This lab was developed using the internet as a resource.  Where ever possible available image sources are cited.  The hardcopy karyotypes were generated from a lab manual copy of a basic karyotype by cutting and pasting.   There are usually 12-14 different karyotypes handed out in each class so that students can use their neighbor as a resource not a source.   Included as another link are just the student directions that can be printed for a hardcopy.

Nancy Hein
Hawley HS
Hawley, TX

nanhei@hawley.esc14.net
 
References:
UW Pathology Department Cytogenetics Gallery http://www.pathology.washington.edu/Cyto_gallery/Cyto_gallery_page.html

Utah Medical Library - Web Path
http://www-medlib.med.utah.edu/WebPath/webpath.html

Online Mendelian Inheritance in Man - OMIM
http://www.hgmp.mrc.ac.uk/omim/searchomim.html

Cri-Du-Chat Syndrome Support Group
http://www.cridchat.u-net.com/

TSS News Group - Turner Syndrome Society
http://www.onr.com/ts-texas/
http://laran.waisman.wisc.edu/fv/www/lib_turn.htm

Pediatric Database (PEDBASE)
http://www.icondata.com/health/pedbase/index.htm

Med-line NLM's search service to access the 9 million citations in MEDLINE
http://www.medpatients.com/medline.htm