<p> Human Inheritance Lab</p><p>. Ear lobes (E): o Free ear lobes- homozygous dominant o People with attached earlobes are recessive. . Eye color (B): o Blue- homozygous recessive o Green/ hazel- heterozygous o Brown- homozygous dominant . Widow’s Peak (W): o A hairline that forms a downward point in the middle of the forehead – heterozygous o A smooth hairline is caused by a recessive genotype. . Tongue roller (T): the ability to roll their tongues into a “U” shape when it is extended. o Roller- heterozygous o People with the recessive alleles cannot roll their tongues. . Tongue folder (F): the ability to fold their tongues over while sticking it out. o Folder- homozygous dominant o People with the recessive genotype cannot. . Bent Little Finger (L): the end joint of the little finger of each hand bending inward. o Big bend- homozygous dominant o Little bend- heterozygous o Straight little fingers are a result of the recessive genotype. Place your hands on a flat surface, palms down, and relax. Check to see if the first joints of your little fingers are bent or straight. . PTC Taster (P): Individuals who can taste the bitter chemical phenylthiocarbamide, o PTC taster- heterozygous o Those with the recessive genotype cannot taste it. Taste the strip of control paper. Then taste the strip of PTC Paper to see if there is a difference or not. . Mid-Digital Hair (H): Individuals who have hair on the middle joints of their fingers o Hair- Homozygous dominant o Those with two recessive alleles do not have hair on the joint. . Red hair (R ): o Dark hair- homozygous dominant o Light hair- heterozygous o Individuals with red hair have the recessive genotype. . Curly hair (C ): o Curly hair- homozygous dominant o Wavy hair- heterozygous o Straight hair- homozygous recessive . Eye lashes (Y): o Long- homozygous dominant o Medium- heterozygous o Short- homozygous recessive . Freckles (K): o Lots- homozygous dominant o Some- heterozygous o None- homozygous recessive . Dimples (D): o 2- homozygous dominant o 1- heterozygous o None- homozygous recessive . Cleft Chin (M): o No cleft- homozygous dominant o Cleft- homozygous recessive . Hitchhiker’s thumb (J): A person that can bend the last joint of the thumb to approximately a 45 degree angle o No- homozygous dominant o Yes- homozygous recessive . Index Finger Length (I): If the index finger is shorter than the ring finger (4th finger next to the pinky) o Shorter- homozygous dominant o Same- heterozygous o Longer- homozygous recessive . Hallux Length (G): Individuals with the big toe shorter in comparison to the second toe o Shorter- homozygous dominant o Same- heterozygous o Longer- homozygous recessive . Left-over-right thumb crossing (Q): When the hands are folded in a natural fashion, the left thumb crosses the right thumb in a dominant genotype. If reversed, a recessive genotype is present. o Left-thumb cross- homozygous dominant o Reverse- homozygous recessive Trait Person 1 Person 2 Punnett Square Genotype Most likely genotype genotype probabilities phenotype Ear lobes </p><p>Eye color</p><p>Widow’s peak</p><p>Tongue roller</p><p>Tongue folder</p><p>Bent little finger</p><p>PTC taster</p><p>Mid-digital hair Red hair</p><p>Curly hair</p><p>Eyelashes </p><p>Freckles </p><p>Dimples</p><p>Cleft chin</p><p>Hitchhikers thumb</p><p>Index finger length</p><p>Hallux length</p><p>Left-over- right Class Discussion</p><p>1) If a man does not have Hitchhiker’s thumb, what are the two possible genotypes?</p><p>2) If a man is homozygous for Hitchhiker’s thumb and marries a woman with homozygous dominant alleles, what is the probability of them having children with Hitchhiker’s thumb?</p><p>4) Is anyone dominant for every trait? Is anyone recessive for every trait? If not, what does this show about dominance and recessiveness of traits in people?</p><p>5) Two people that look alike have thousands of common traits. How often do you think that genetic twins (aside from identical twins) exist? Explain your answer.</p><p>6) What is the ratio of tongue rollers to non-tongue rollers in the class? What is the frequency (%) of tongue rollers in the class?</p><p>7) What is the ratio of dimples to non-dimples in the class? What is the frequency (%) of dimpled students in the class? ( # of people with dimples/ total number of people) </p>