Genetics and old clothes

This is a visual way of demonstrating that:
• recessive alleles are masked by dominant ones (for instance you can’t see a vest worn under a t-shirt, but it is still there)
• occasionally both alleles are expressed (both would be visible) and are therefore said to be co-dominant.

Apparatus
Collection of old clothes which are easy to get on and off
– at least two garments which can be worn on the head, the torso, the hands, the feet, and so on. Examples are t-shirt, jumper, ordinary shirt, vest, socks, flippers, shoes, gloves, mittens, trousers, skirts, swimming cap, picture hat, and beanie hat.

Procedure
1 Divide the clothes into two sets for each region of the body (i.e. clothes worn on the torso, clothes worn on the feet, clothes worn on the head, etc). Clothes that come in pairs should be pegged together with a clothes peg, and count as one garment.

2 Put each set into a plastic bag or black bin-liner. Each of pairs of bags represent a maternal and paternal gene, with the garments inside representing alleles.

3 Select a volunteer, who then picks one garment from each bag in a pair (without looking), and then puts them on. Repeat for the other pairs of bags.

Last updated: 31 March 2008