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

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

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

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

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

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

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

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.