1. What is a homologous chromosome?
Objectives
What is a karyotype?
What are homologous chromosomes?
Differentiate between autosomes and sex chromosomes.

2. Karyotype
A karyotype is a picture of ALL a person’s chromosomes

3. Autosomes vs. Sex Chromosomes
There are two types of chromosomes
Sex chromosomes are chromosomes that determine gender
XX = female
XY = male
These are the 23rd pair on a human karyotype
Autosomes are any chromosomes that are not sex chromosomes
These are pairs 1-22 on a human karyotype

4. Check for Understanding
How many chromosome pairs do you have?
Are your sex chromosomes XX or XY?
Where do the pairs come from?

5. Chromosome Pairs
In each pair, one chromosome comes from mom and one comes from dad
Each pair of chromosomes is referred to as a homologous pair

6. What are homologous chromosomes?
Homologous chromosomes are a pair of chromosomes
They have the same size and shape with the same organization.
Most importantly, they have the same genes but the version of the gene may be different.
Example:
Gene=eye color
Version= brown eyes or blue eyes

8. Check for understanding:
Are homologous chromosomes identical to each other? Explain.

9. Check for Understanding- Answer
No, they are very similar in size and shape and carry the same type of genes, but the version of the genes may differ.