Pedigree Chart Activity Worksheet (Page 4 of 4) in pdf

Now: Using the guide provided, determine the genotypes of all individuals in this pedigree chart for freckles. Remember, having no

freckles is a RECESSIVE trait.

GUIDE

STEP 1

Assign two recessive genes to any person on the pedigree whose symbol is shaded. Small letters are written below the person s

symbol.

STEP 2

Assign one dominant gene to any person on the pedigree whose symbol is unshaded. A capital letter is written below the person s

symbol.

STEP 3

Use the information given to you to determine the second alleles for each person with the dominant phenotype.

Example: We know that Grandpa Flipnob does not have freckles. If Grandma were BB, could any bb children be produced from

Grandma and Grandpa? If Grandma were Bb, could any bb children be produced from them? Do Punnett squares below to determine

your answer.

From your results, what is Grandma s genotype? ____________________

What must be the genotypes of their children? ____________ ____________

(2nd generation)

Fill in these genotypes (along with Grandpa s) beside the appropriate circles and squares.

Complete this process until the entire pedigree is completed.

Sex-Linked Inheritance - Colorblindness

To complete this part of the activity, you will need to make a copy of your pedigree chart. There is no guide to go along with this

section. Just remember to determine the genotypes of those possessing the sex-linked trait first. From there, using Punnett squares, you

should be able to determine the genotypes of most, if not all of the family.

Neither Grandma or Grandpa Flipnob are colorblind.

All of their children have normal color vision, except for Mickey.

Of the grandchildren, the twins both inherited colorblindness, as did their cousins, Barney and Janet.

There still remains one colorblind person in this clan, however, that is up to you to determine who.

What are the genotypes of the individuals in the Flipnob family for colorblindness?

Pedigree Chart Activity Worksheet Page 4