Reebops

• Difference coloured pieces of paper - pink and blue make the genders obvious.
• A felt tip pen
• Large pink and white marshmallows - more than you think you will need because you will eat some.
• Small white marshmallows
• Cocktail sticks
• Coloured map pins (blue, yellow and red)

1. Cut strips of paper to represent the reebops chromosomes. There will be 8 pairs of each length in each colour. If each strip is 2cm wide you'll need two pieces of each coloured paper. Start with the pink, cut two strips of each length…20cm, 18cm, 16cm, 14cm, 12cm, 10cm, 8cm and 6cm. You are left with 16 strips of pink chromosomes - repeat the process with the blue paper.
2. Arrange the same length strips next to each other. Now write on each strip in felt tip. On the first pink pair write 'A' on one and 'a' on the other, do the same with the longest blue strips.
3. Repeat this with the remaining chromosomes so you have…
   Aa on 20cm
   Bb on 18cm
   Tt on 16cm
   Nn on 14cm
   Ll on 12cm
   Ee on 10cm
   Hh on 8cm
   XX (pink) or XY (blue) on 6cm
4. What you will end up with is a complete set of pink chromosomes - 8 pairs, and a complete set of blue chromosomes, again 8 pairs.
5. To make this totally random you can turn them over so you can't see the letters.
6. Now create the genetic make up of your baby reebop - pick one from each of the pairs of pink chromosomes to create the egg cell. Then repeat with one from each of the pairs of blue chromosomes to make a sperm cell.
7. Now fuse the chromosomes from the egg and sperm cells by matching up the same length of chromosome until you have a new set of 8 pairs. Turn them over so you can see the letters.
8. Now you can start to construct your baby reebop…
   The following list tells you the features your reebop will have…
9. AA antennae         Aa antennae         aa no antennae
   BB 3 body parts    Bb 3 body parts    bb two body parts
   TT curly tail           Tt curly tail           tt straight tail
   NN red nose          Nn red nose        nn yellow nose
   LL blue legs          Ll blue legs           ll red legs
   EE two eyes         Ee two eyes         ee one eye
   HH one hump        Hh one hump       hh three humps
   XX Female            XY male
10. Follow the genetic instructions to construct your baby reebop - use the cocktail sticks to attach the body and head then attach any humps, legs, eyes and antennae with map pins. You may want to construct female reebops from pink marshmallows and male reebops from whites ones.

In meiosis, cells split to create egg and sperm cells which randomly contain half the genetic material of the parent cells. When these fuse to create the first cell of the new reebop they contain a random mix of both the mother's and the father's chromosomes.

These chromosomes contain dominant and recessive genes. The dominant genes, which are shown with capital letters, will express their characteristic - having a red nose or blue legs. It is only if this dominant gene is absent that the recessive gene can express itself - producing red legs or a yellow nose.

Do not eat the reebops you have made as they may contain concealed cocktail sticks or map pins (always keep a supply of fresh marshmallows if you feel you have to eat some).