LAB FLIP-A-COIN-GENETICS Why are even closely related siblings different both in genotype and phenotype? They differ because the variety of traits in a human population is very large and reproduction continually creates new combinations of traits. What traits would your baby have at age sixteen if both you and a classmate (your make-believe spouse) are heterozygous for each trait listed in the following pages? Illustrate how inherited traits are determined by chance with the following simulation. As you proceed with this simulation, keep in mind that actual inheritance is much more complicated than this exercise implies, and that geneticists do not fully understand the process. Procedure 1. 2. Pair up into make-believe parents. Determine the genotype and phenotype for each trait in this manner: a. Each parent flips a coin. b. “Heads” indicates that the parent flipping the coin contributes the dominant allele to the offspring (represent with a capital letter). c. “Tails” indicates that the parent flipping the coin contributes the recessive allele to the offspring (represent with a lower-case letter). Guide for determining individual traits Gender Only the “father” flips because he determines the child’s gender. Heads = girl, tails = boy Hair Color Dark color is dominant over light. At least four gene pairs are involved in determining hair color. Use the same procedure as for skin and eye color and please add another column to the chart, if necessary. Face Shape Choose one on page 16-10 as follows: Round (RR, Rf) Square (rr) 52010 Face/Head Variation Lab 16-2 52010 Face/Head Variation Lab 16-3 52010 Face/Head Variation Lab 16-4 52010 Face/Head Variation Lab 16-5 52010 Face/Head Variation Lab 16-6 52010 Face/Head Variation Lab 16-7 52010 Face/Head Variation Lab 16-8 Name___________________________ Face & Head Variation Report Sheet Parents’ Names __________________________________________________________ Child’s Name______________________________ Sex________________ Table 1. Face & Head Variations TRAIT Face shape Chin shape Gene(s) from Mother Gene(s) from Father Genotype Phenotype Cleft chin Skin color Hair type Widow’s Peak Eyebrows (I) Eyebrows (II) Eyebrows color Eyes-distance apart Eyes-size Eyes-shape Eyes-slant Eyelashes Eye color Mouth size Lips Lower lipprotruding Dimples Nose size Nose shape Nostril shape Earlobe Attachment Freckles on checks Hair color 52010 Face/Head Variation Lab 16-9 Face & Head Shape 52010 Face/Head Variation Lab 16-10