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1. Karyotypes
Essential Question: What is a karyotype and what are
they used for?

2. A karyotype is a picture of your
chromosomes.
Where did these chromosomes come from?
CC image courtesy Andreas Bolzer on Wikimedia Commons

3. Where did your chromosomes
come from?
Half your chromosomes came from your mom, and
the other half came from your dad.
The last pair tells you the
biological gender of the
individual.
XX means the individual is
biologically female
XY means the individual is
biologically male

4. Since females only carry X chromosomes,
mothers always pass an X to their offspring.
Half of a father’s cells carry an X chromosome,
and the other half carry a Y chromosome.
CC image courtesy Ageremia on Wikimedia Commons

5. Karyotypes are analyzed by a
cytogeneticist.

6. What are karyotypes used for?
• Geneticists use karyotypes to determine if an
individual has any chromosomal disorders.
• First, they check to the total number of
chromosomes (there should be 46 on a human
karyotype).

7. Note: Different species will have a
different number of chromosomes.
Dog 2n= 78
CC image courtesy Junko Maeda on Wikimedia Commons
Orangutan 2n= 48
CC image courtesy Doron Tolomeo on Wikimedia Commons

8. Is this individual healthy?
Do you notice any abnormalities?

9. Is this individual healthy?
Do you notice any abnormalities?
An extra
chromosome at
location #21 results
in down syndrome

10. An individual having more or fewer
chromosomes than they should is
caused by nondisjunction.
During metaphase of meiosis, the
chromosomes do not separate properly.

11. Is this individual healthy?
Do you notice any abnormalities?

12. Most often, if an embryo is missing or
has extra chromosomes, a miscarriage
results.
A few exceptions include:
• Turner Syndrome- Females missing an X chromosome
• Klinefelter syndrome = XXY
• Triple X syndrome = XXX
• Trisomy 13 = Patau syndrome
• Trisomy 18 = Edwards syndrome
• Trisomy 21 = Down syndrome

13. Can you be a cytogeneticist?
https://learn.genetics.utah.edu/content/basics/karyotype/