NAME: __________________________________________ DATE: _____________
HUMAN KARYOTYPING LABORATORY
Background: Occasionally chromosomal material is lost or rearranged during the
formation of gametes or during cell division in early embryo. Such changes, primarily the
result of nondisjunction or translocation, are so severe that the pregnancy ends in
miscarriage-or fertilization does not occur at all. It is estimated that one in 156 live births
have some kind of chromosomal abnormality.
Some of the abnormalities associated with chromosomes structure and number can
be detected by a test called a karyotype. A karyotype can show prospective parents whether
they have certain abnormalities that could be passed on to their offspring, or it may be used
to learn the cause of child’s disability. Karyotypes can also reveal the gender of a fetus or
test for certain defects through examination of cells from uterine fluid-a procedure called
amniocentesis-or through sampling of placental membranes. Over 400,000 karyotype
analyses are performed each year in the U.S and Canada.
To create a karyotype, chromosomes from a cell are stained and photographed. The
photograph is enlarged and cut up into individual chromosomes. The homologous pairs are
identified and arranged in order by size (with the exception of the sex chromosomes; these
appear last). These tests are typically done a sample of blood, although any body cell could
be used. The cell must be undergoing mitosis-preferably in metaphase-so that the
chromosomes are replicated, condensed, and visible under a microscope. (Adapted from:
http://www/slic.wsu.edu/bios/biol107/107Karyotypesp05.pdf )
Purpose: The purpose of this laboratory experience is:
1. Understand what a karyotype is and how it is performed.
2. Understand the reason for performing a karyotype, especially for those with a
higher risk of genetic defect in their lineage.
3. To determine what genetic defect is present in a chromosome sample.
4. To investigate a variety of genetic disorders that commonly occur and are studied
in biology classes.
Materials: The following materials are needed to perform this laboratory experience.
- Scissors - Ruler - Tape - Small envelope
Procedure: The following procedure is utilized to perform this laboratory experience.
1. Using the attached sheets, complete the four different karyotypes: One normal male, one
normal female, two different disorders of your choice out of the four. Additional
laboratory minutes may be granted for work above beyond the four required
karyotypes.
2. Working slowly and carefully, using scissors cut the chromosome on one page labeled “1”
and find its EXACT match elsewhere on the page (it will not be numbered). Cut this
chromosome and tape BOTH chromosomes side by side on the “data page’ that has the
heading filled out.
3. Continue this procedure until you have matched all chromosomes and taped each of them
in the corresponding place on the data page.
4. If you are caught short of time, use the coin envelope to store any chromosomes you may
have clipped out and do not matched. DO NOT CUT OUT ALL CHROMOSOMES AND
THEN ATTEMPT TO MATCH THEM!!! Cut out only one at a time or you will lose
chromosomes.
5. In the event that you have an extra chromosome, DO NOT THRW IT OUT! It is the
chromosome that causes your mutation/disorder and you must match it correctly.
6. Once your chromosomes are all cut out and included in the karyotypes, answer the
questions and complete the lab.
Questions: Answer the following questions before turning in your lab.
1. What four karyotypes did you choose to complete?
2. How could you determine if your karyotype was male or female?
3. Complete the following table.
Karyotype # 1 Karyotype # 2
Individual is a __________________________ Individual is a __________________________
Number of Chromosomes: _______________ Number of Chromosomes: _______________
What is the sex? ________________________ What is the sex? ________________________
(Normal or Mutated) (circle one) (Normal or Mutated) (circle one)
If mutated, name the disorder below: If mutated, name the disorder below:
___________________________________ ____________________________________
Karyotype # 3 Karyotype # 4
Individual is a __________________________ Individual is a __________________________
Number of Chromosomes: _______________ Number of Chromosomes: _______________
What is the sex? ________________________ What is the sex? ________________________
(Normal or Mutated) (circle one) (Normal or Mutated) (circle one)
If mutated, name the disorder below: If mutated, name the disorder below:
____________________________________ ____________________________________
For this activity you will need to access the following page: (it is also on my website-click on
Biology, Schedule, and go to date-there is a link there!)
http://www.biology.arizona.edu/human_bio/activities/karyotyping/karyotyping.html
1. Read the introduction and answer the following questions.
A. What is a karyotyping?
B. How many pairs of chromosomes are present in a human cell?
C. What is the purpose of the Geimsa Dye?
2. Read your “assignment”. Then click on PATIENT HISTORIES. Begin by clicking
on PATIENT A.
3. Once you have correctly completed the karyotype for patient A, read the information and
answer the following questions.
A. How many chromosomes does Patient A have?
B. What notation would you use to characterize Patient A’s karyotype?
C. What diagnosis would you give Patient A?
4. Proceed to the history of Patient B. Complete the karyotype and answer the following
questions.
A. How many chromosomes does Patient B have?
B. What notation would you use to characterize Patient B’s karyotype?
C. What diagnosis would you give Patient B?
5. Proceed to the history of Patient C. Complete the karyotype and answer the following
questions.
A. How many chromosomes does Patient C have?
B. What notation would you use to characterize Patient C’s karyotype?
C. What diagnosis would you give Patient C?
Analysis Questions.
1. How is karyotyping helpful?
2. What chromosome pair determines the sex of the baby?
3. Which parent determines the sex of the baby?
4. What ethical issue can arise when performing genetic screenings in pregnancy?
