Punnett Square Activity
Procedure
- Study the genetic problems below. Complete the Punnett Square for each by first writing the parental genotypes in the correct place. Determine the possible genotypes of the offspring. For each combination, describe the trait the offspring would exhibit, which is called the phenotype.
 Silkworms dominant gene: yellow cocoon (C) recessive gene: white cocoon (c) parents: CC x cc List possible genotypes and phenotypes: |
Guinea pigs dominant gene: short fur (F) recessive gene: long fur (f) parents: Ff x ff List possible genotypes and phenotypes: |
Mice dominant gene: black eyes (E) recessive gene: red eyes (e) parents: Ee x Ee List possible genotypes and phenotypes: . |
Roses dominant gene: red flowers (F) recessive gene: white flowers (f) codominance: pink flowers (Ff) Parents: white flower x pink flower List possible genotypes and phenotypes: |
Genetic Survey
Complete this page by surveying at least 50 individuals in your school or area. Use tally marks next to the trait to record each person’s traits.
| Hairline | Totals | |
| Widow's peak present | ||
| Straight hairline | ||
| Ear Lobes | ||
| Attached ear lobes | ||
| Free ear lobes | ||
| Tongue Rolling | ||
| Can roll tongue | ||
| Cannot roll tongue | ||
| Thumb | ||
| Hitch-Hikers thumb | ||
| No hitch-hikers thumb | ||
| Interlocking Fingers | ||
| Right thumb on top | ||
| Left thumb on top | ||
| Hair on Fingers | ||
| Mid-digital hair on ring finger | ||
| No mid-digital hair on finger | ||
| Finger Length | ||
| Second finger shorter than fourth | ||
| Second finger same length or longer than fourth finger | ||
| Eye Color | ||
| Brown/dark eyes | ||
| Blue, gray, green eyes | ||
| Vision | ||
| Normal, farsighted | ||
| Nearsighted, colorblind | ||
| Hair Texture | ||
| Curly Hair | ||
| Straight Hair | ||
 |
 |
 |
| Widow's peak comes to a point in the center | Free and attached earlobes | Hitch-hiker's thumb: greater than 60 degree knuckle extension |
