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Each popsicle stick represents a pair of homologous chromosomes. If possible, photocopy the pages for the different chromosomes on different color paper as directed on pages 3-8 of these Teacher Preparation Notes. Once you have cut out the vertical strips of letters, for each of the autosomes and for the sex chromosomes for females, choose any two strips (which will have the same genes, but in many cases different alleles) to paste on the two sides of a popsicle stick. For males, you must match an X chromosome (which has the 5 letters and the + or - for non-fire breather versus fire breather) for one side of the popsicle stick and a Y chromosome (which has only three letters) for the other side of the popsicle stick which will represent the pair of sex chromosomes for a male.

It is important to think in terms of the biological processes of meiosis and fertilization as students do this activity. Once each student has five popsicle sticks (one of each color autosome in one sex chromosome stick), the student drops these sticks on the table to simulate meiosis. The side of the stick that is up represents the chromosome (from each pair of homologous chromosomes) that is in the gamete which will take part in fertilization to form the zygote that develops into the baby dragon. Thus, the alleles on the side of the popsicle stick that is up are the alleles in the egg or sperm and they should be recorded in the appropriate columns of the tables on pages 3 and 4 of the Student Handout; these alleles are then used to determine the phenotypic traits of the baby dragon. In these tables, the genotypes of the parents are the two alleles for each gene on each of the chromosomes.

Ingrid