Student's Name: Date of Experiment: September 21, 2013 Date Report Submitted: September 28, 2013 Title: Experiment 8: Phenotype and Genotype Purpose: The purpose of the experiment is to let students compare, analyze and determine phenotype and genotype Procedure: The student’s phenotype and genotype were determined for dimpled chin, free ear lobe, ability to taste PTC, interlocking fingers, mid-digital hair, bent little finger, Widow’s peak, hitchhiker’s thumb, pigmented irises and long palmar muscle in accordance with the conditions for having a dominant and recessive trait. An exercise was done to determine genotype and phenotype ratios possible for offspring if parents are heterozygous brown-eyed individuals with dimpled chin. Data Tables: Summary Table: Trait Phenotype Genotype 1.Dimpled chin recessive dd 2.Free ear lobes recessive ff 3.Ability to taste PTC recessive pp 4.Interlocking fingers recessive ff 5.Mid-digital hair dominant MM(homozygous dominant) or Mm(heterozygous dominant) 6.Bent little finger recessive bb 7.Widow’s peak recessive ww 8. Hitchhiker’s thumb recessive hh 9. Pigmented irises recessive ii 10. Long palmar muscle recessive mm Observations: From the table, it can be deduced that the student is mostly of recessive type for the traits specified. It was only the mid-digital hair that was the dominant trait. It can be deduced further that a phenotype that was recessive, the genotype was a homozygous recessive. For a dominant phenotype, the genotype was either a homozygous or heterozygous dominant. Questions/Exercise: Refer to the previous experiment and construct a Punnett square showing both the genotype and phenotype ratios possible if two heterozygous brown-eyed individuals with dimpled chins were to have children. Your Punnett square will be 4 x 4squares. Assume both independent assortment and segregation are occurring. Solution : Since both parents are heterozygous and there are two genes, each parent has the following genotype BbDd. B = brown eyes b = other eye color (non-brown) D= with dimple chin d= not dimple chin There are four combinations possible BD, Bd,bD and bd then constructing the 4x4 Punnet Square: Punnet Square: BD Bd bD bd BD BBDD BBDd BbDD BbDd Bd BBDd BBdd BbDd Bbdd bD BbDD BbDd bbDD bbDd bd BbDd Bbdd bbDd bbdd Phenotype Classification: BD Bd bD bd BD BBDD BBDd BbDD BbDd Bd BBDd BBdd BbDd Bbdd bD BbDD BbDd bbDD bbDd bd BbDd Bbdd bbDd bbdd legend: green = offspring with brown eyes and with dimple chins yellow= offspring with brown eyes but no dimple chins blue = offspring with non-brown eyes color but with dimple chins red = offspring with non-brown eyes color and no dimple chins Interpretation: From the Punnet square and from the color scheme, it can be seen that there are 9 offspring with brown eyes and with dimple chins, 3 offspring with brown eyes but no dimple chins, 3 offspring with non-bro.