Columbia
Hiqh School
BIoLoGY Lae
Student's Name:
Teacher:
Lab Day:
Problem: How can we use a karyotype to determine genetic defects?
Introduction: A karyotype is a chart showing all of the chromosomes within a cell. Genetic counselors
use karyotypes to identify abnormal conditions caused by extra or missing chromosomes. Karyotypes
are made by cutting out the chromosomes taken from a photograph of a dividing cell during metaphase
and arranging them in order of chromosome size. In this activity you will use an on-line site to prepare a
karyotype and then diagnose a genetic disorder based upon a karyotype that is presented to you.
Procedure Part I:
1. After signing on to the computer, launch Internet Explorer and set the browser to the following URL:
http://learn.genetics.utah.edu/content/begin/traits/ Click on the link that says: "How Do Scientists Read
Chromosomes?"
2. Read through the first page and complete the activity on the right.
Which chromosome in Box B matched the chromosome on the left?
What three characteristics of chromosomes are useful in identifying pairs?
3. Use the back alrow and return to the original page. Click on the link "Make A Karyotype"
Complete the activity: "Matching Up Chromosomes in a Karyotype
- Try it Yourself'
Was the karyotype you created a male or female? How could you tell?
4. Return to the original page and click on the link: "Using Karyotypes to Predict Genetic Disorders."
What process(es) is (are) responsible for making sure that a person receives the correct number
and type of chromosomes?
What might happen to cause a person who ends up with too few or too many chromosomes?
What chromosomal abnormalities result in each of the following genetic disorders:
Down Syndrome:
Turner Syndrome:
Klinefelter Syndrome:
Define trisomy
-
Define monosomy
-
What are chromosome deletions?
Name two disorders that are caused by chromosome deletions.
What happens during a translocation?
What cannot be seen in a karyotype?
5. Complete the Test Your Knowledge euiz.
Procedure Part
II:
After you have read about the different types of abnormal karyotypes reset your browser to the following
URL: http:
.bio
edu&
ins.h
In this section, you will analyze the karyotypes of three "patients" and determine what the information
reveals.
Patient A:
what notation would you
use to characterize patient
A's karyotype.
What is the patient's diagnosis?
Patient B:
what notation would you use to characterize patient B's karyotype.
What is the patient's diagnosis?
Patient C:
what notation would you use to characterize patient c's karyotype.
What is the patient's diagnosis?
Procedure Part III
Now, the final part of this lab is to search the internet for web sites that cover some interesting aspect
of
human genetics.
An excellent way to conduct internet searches is to use a meta-search engine such as Dogpile
fhttp:ttwww.AoeDile.cod or Metacrawler (http://www.metacrawler.com). At these si-tes, when you
type in key words, they will search all of the major search engines on the *.t *d compile ih.
r*rult fo,
you in a nice, friendly format.
After you conduct your internet search, on the page with your abstract labeled ..Part IIIrr, add the
web
address of a human genetics web site that you like, the title of that site, and a 2-3 sentence
sunmary of the
site's content.