Background Information

Karyotypes are used to study the genomes of organisms. To construct a karyotype, scientists stop cells undergoing cell division and stain and separate the chromosomes by size and shape. All humans have 23 pairs of chromosomes. The first 22 pairs are homologous and are called autosomes. The 23^rd pair are the sex chromosomes. Females have 2 X chromosomes; notice that they are identical in the image below. Males only have 1 X chromosome; notice that the "Y" chromosome is much smaller.

Female Sex Chromosomes (XX) Male Sex Chromosomes (XY)

Female sex chromosomes Male sex chromomsomes

(Image source: https://www.flickr.com/photos/47988426@N08/8252270882/in/photolist-dze3Cs-onihyb-o7Qwm1-or65eD-onihEd-o7Qxf6-gwjUoN-5AZA5d-novNmM-nCWr6f-notRQg-noq8hW-nosvaG-nMgG53 by Can H., modified by Anne Scott)

In this lab, we will construct a human karyotype and gather information about the organism’s genome.

Materials

Chromosome cut outs
Chromosome mat
Scissors
Glue or tape
Computer
Printer
Paper

Procedure

Print these chromosomes out. (Image source: https://www.flickr.com/photos/47988426@N08/8252270882/in/photolist-dze3Cs-onihyb-o7Qwm1-or65eD-onihEd-o7Qxf6-gwjUoN-5AZA5d-novNmM-nCWr6f-notRQg-noq8hW-nosvaG-nMgG53 by Can H., modified by Anne Scott)
Cut each chromosome out individually.
Arrange the chromosome in size order, from largest to smallest.
Each chromosome should have a pair.
Copy the table below into your interactive notebook.
Glue or tape the chromosomes in the blank with the chromosome number.

Hint: The 23^rd pair is the sex chromosome pair and both chromosomes may not be the same size.

Chromosome Mat – Copy this table into your notebook.

Chromosome mat

(Image credit: https://cedu-spw-p06.austin.utexas.edu/canvas-files/BioB-66432/unit09/lsn03/U09L03EX03.jpg by Anne Scott)

Post-Lab Analysis:

Based on the investigation findings outlined above, answer the following questions in your interactive notebook in complete sentences:

How many chromosomes are in this karyotype?

According to this karyotype, does this genome belong to a male or female? Justify your answer.

What was the most difficult part of this simulation?

View the Completed Karyotype to check your work.

(Image source: https://www.flickr.com/photos/47988426@N08/8252270882/in/photolist-dze3Cs-onihyb-o7Qwm1-or65eD-onihEd-o7Qxf6-gwjUoN-5AZA5d-novNmM-nCWr6f-notRQg-noq8hW-nosvaG-nMgG53 by Can H.)