BAG O’ GENES CONTENTS of each bag: 1. 8 popsicle sticks – Each popsicle stick represents the haploid, or single chromosome of a pair. Female - 4 egg cells Male – 4 sperm cells Alleles: Female – eggs – 2 dominant alleles and 2 recessive alleles Male – sperm – 2 dominant alleles and 2 recessive alleles D = dominant and R = recessive 2. Worksheets: 2 pages of facial traits 3. Worksheets: Human Face outlines 4. Worksheet: Wrap it Up! - questions PART ONE – SINGLE ALLELIC TRAITS Human facial features have been analyzed from the shape of the head to presence of dimples. These facial features are visible to us and are the expression of our genes. These are called phenotypes. In this activity, these facial features are determined by a single gene with two forms (alleles). These dominant and recessive alleles are inherited from an individual’s parents. Allelic combinations are our genotype. ACTIVITY – work in pairs or threes In this activity, you will build a family tree. You will start with using the genes on sticks to generate genotypes and then draw the facial features (phenotypes) of the Mom and Dad. Then you will use these genotypes and punnet squares to demonstrate your knowledge of the Mendelian laws of inheritance to describe their offspring. ACTIVITY: BUILDING A FAMILY TREE – Step 1: MEET THE PARENTS: What are the genotypes of the parents? To build the genotypes, you will use the popsicle sticks. Example: Shape of Head 1. Turn the 8 sticks over so that you can only read “sperm” and “egg” 2. Select one sperm cell and one egg cell. 3. Flip these two popsicle sticks over. a. Keep the stick flipped over so you can read: the male allele (D or R) b. Keep the stick flipped over so you can read: the female allele (D or R) 4. Go to the worksheet and decode using the lettering system on the worksheet. Eg. Shape of Face – ROUND (RR) and (Rr) or SQUARE (rr) If I got a sperm cell popsicle stick “D” and an egg cell popsicle stick “R”, the genotype is Rr the phenotype is Round This is a heterozyogote! (Huhh, A what kinda goat?) 5. Use the work sheet to keep track. On the worksheet showing each facial feature and the different geno/pheno-types, mark the square that matches your genotype using “F” for female and “M” for male. 6. CONTINUE FOR EACH HUMAN FACIAL TRAIT (from shape of head to dimples)! I wonder, can you guess your genotypes? 7. Using the human face outlines, draw a representation of the Mom and the Dad! Give them names! If you want to decide on hair and eye colour, see page 3 STEP TWO: Using the parents’ genotypes, what will their children look like? Let’s imagine that these parents have 4 children. 8. Do punnet squares, for a SELECTION of facial traits do a hybrid cross. Record the data here: # that are dominant DD, # heterozygous (Dd), and # recessive (dd) Record the name of the trait # Dominant (DD) # Heterozygous (Dd) # Recessive (dd) JUST FOR FUN!! – what is your genotype? Hair and Eye Colour. Ever wondered about your hair and eye colours? These are ”polygenic traits”. At least two genes determine the colour. Genes code for proteins in pigment cells. As the quantity of proteins varies, so too does colour If the The hair genotype is: colour is The eye colour is AABB AABd AAbb AaBB Aabb AaBd aaBd aaBd Aabb Dark brown Dark brown Brown Brown w green flecks Brown Grey Green Dark blue Light blue Black Black Red Brown Regular blonde Brown Dark blonde Regular blonde Pale yellow blond Your Hair Your eyes (genotyp (genotype e)
