Karyotype
A karyotype is an organized
profile of a person's chromosomes. To make a karyotype, scientists take a
picture of the chromosomes from one nucleated cell; usually a white blood cell,
cut the chromosomes out, and arranges them in pairs by size from largest to
smallest(with the exception of sex chromosomes), banding pattern, and
centromere position. This arrangement helps scientists quickly identify
chromosomal alterations that may result in a genetic disorder. Two chromosomes
specify gender — XX for female and XY for male. Thus, a karyotype can also
reveal the gender of a fetus and test for certain defects through examination
of cells from uterine fluid – a procedure called amniocentesis – or through
sampling of placental membranes. Moreover, 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 a child’s disability.
In this session, participants
will investigate how karyotyping is performed in the lab. They will be engaged
in several interactive activities that would enhance their understanding of
this technique. Participants will infer that chromosomes are the carriers of
genetic information by evaluating case histories of patients with different chromosomal
set. Additionally, participants will use several technological tools (image
editor; desktop publishing software; Google docs; and web sites) to identify
common diseases associated with chromosomal abnormalities and share findings
with other group members.
