Introduction

                                                                   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.