CTYOGENETIC LAB - KARYOTYPING
There are several genetic disorders that
involve entire chromosomes. The objective of this lab will be to:
1) analyze a set of chromosomes
and determine if there is a genetic disorder
2) investigate the possible effects
of the disorder in your karyotype
3) explore other types of
disorders using the computer and comparison of karyotypes with other
lab groups
4) be able to define deletion,
inversion, translocation, monosomy, and a trisomy chromosome mutations
PROCEDURE:
-
Obtain a set of chromosomes
-
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.
-
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.
-
Research your abnormality using the resources
available. A photograph of a real karyotype for the disorder is in
the computer database.
-
Locate examples of the five types of chromosome
abnormalities using the computer or karyotypes from other lab groups
in the room.
SIMPLE KEY FOR DIAGNOSING CHROMOSOME ABNORMALITIES
-
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
INFORMAL LAB REPORT
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Explain what the word cytogenetics means.
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Briefly discuss the chromosome abnormality
in the karyotype you analyzed. 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
in your discussion.
-
Using your knowledge of meiosis discuss how
the chromosome abnormality could have occurred.
-
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?
-
Karyotyping can be used as a prenatal screening
tool. Is a baby guaranteed from genetic disorders if the chromosome
configuration appears normal? Explain.
Link to Database