Duration of activity: 25 minutes

Suitable for:Pupils S4 and older. There is a single gene cross game for younger students.

Powerpoint explanation for pupils

Game cards   SIZE face of cards SIZE back of cards COAT face cards COAT back of cards

Game sheet

This is a game we run in our GM workshops, but it is relevant to many aspects of genetics.

Preparation

Print out game cards - use different coloured paper for the size cards and the coat cards. Each pupil will need a set of cards, and each set, should have two size cards (big and wee) and two coat cards (woolly and baldy): four cards in total. If you have time, label each set with a different number, so that they don't all get mixed up, creating havoc with the ratios!

Print out game sheets one for each pair of pupils.

Method

The pupils will work in pairs, but each pupil needs full set of genes (four cards). They place the cards face down on the table.

Each pupil is a sheep parent. Explain that thay have two sets of chromosomes and there fore two versions of each gene, they got one version/set from their mum and one from their dad.

The pupils are now going to make lambs together. Ask them to make a gamete by randomly selecting just one size gene card and just one coat card. Explain that a gamete is an egg or sperm cell and that those types of cell only have one set of genes.

Get them to combine their gamete with the person sitting next to them, to make a lamb which has two sets of genes.

They can turn over their cards to see what genes their lamb is carrying. They can record these (the genotype) on their sheet.

Using the table of dominance (Baldy and big are dominant, and this is stated on their game sheets) they can work out what their lambs are going to look like (phenotype) and draw a picture.

Get them to reclaim their orginal genes, then repeat the process to make another lamb.

It is useful to collect the frequency of occurence of each of the four possible lamb phenotypes: how many big baldy lambs and how many big woollies etc.

Get the students to predict which will be the most/least common phenotype and let them explain why they predict that.

You should end up with a ratio roughly 9:3:3:1