2. Be a genetic councilor!
People- like all living things- have DNA in their cells which
helps to determine how they look and how they function.
DNA molecules are coiled up around proteins (like thread on
a spool) to make chromosomes.
Chromosomes can be used by genetic councilors to learn
things about people.
Click Genetic Councilors to learn about genetic councilors.
If chromosomes are damaged (chromosomal mutations)
health problems can result.
3. 1. Karyotype
Definition: Picture of chromosomes, can be used to find out the
gender of a person and also to diagnose some genetic
disorders
How is a karyotype made? ( process):
• make chromosomes coil up in cell
• stain chromosomes
• find chromosomes using a microscope
• take a picture of chromosomes
• cut apart chromosomes, pair them up and line them up
according to their number.
4. This picture shows
how the
condensed and
stained
chromosomes
would look
under a
microscope
5. The NEXT slide shows a finished karyotype. Use it to
answer the following questions in your notebook:
What characteristics are used to match up the chromosomes?
Are the chromosomes lined up in the karyotype in any sort of
order? Explain.
How many chromosomes do humans have in each cell?
Why do you think chromosomes come in pairs?
6.
7. Check your answers…..
What characteristics are used to match up the karyotypes?
The bands made by the stains, the length of the chromosomes, the placement of
the centromere
Are they lined up in the karyotype in any sort of order?Yes
Explain- Largest to smallest
How many chromosomes do humans have in each cell? 46
What is the gender of the person for whom this karyotype was made? female
How do you know? 2 X chromosomes
How would the karyotype look different if it were the other gender? There
would be an X chromosome AND aY chromosome
Why do chromosomes come in pairs? One of each pair comes from each
parent
8. Determining gender
Notice that the last pair of chromosomes is labeled with letters
instead of numbers.
The last pair of chromosomes are the sex determining
chromosomes.
The longer chromosomes are called X and the shorter one is called
Y
If the person has one X and oneY chromosome (one long
chromosome and one short chromosome) the person is male
If the person has two X chromosomes ( 2 long chromosomes) the
person is female.
On the next slide determine the gender of patientA and patient B
9.
10. Now try making your own karyotype:
Click this link:
http://learn.genetics.utah.edu/content/begin/traits/karyotyp
e/
11. Karyotypes are used to diagnose
CHROMOSOMAL disorders
Chromosomal
Disorders
Affects a part of or an entire
chromosome (can affect many
genes)
Usually results in a syndrome
(collection of symptoms)
Can result from mutations such as…
• Too many chromosomes
• Too few chromosomes
• Broken or damaged chromosomes
12. How are karyotypes used?
Use the link below to learn
about the procedures used to
obtain cells for karyotyping
http://www.nlm.nih.gov/medli
neplus/ency/article/003935.ht
m
Once you are at this site
research the following and
record your findings in your
notebook:
Normal results for a karyotype
Examples of disorders that can
be detected by an abnormal
karyotype.
13. Be a Genetic Councilor
Click on the patient histories below and for each patient,
complete their karyotype.
In your lab notebook write a brief report for each patient
telling me three things:
1) whether the patient is male or female
2) what is specifically wrong with the chromosomes in the
karyotype
3) what genetic disorder the karyotype shows.
Patient Histories