A half shaded circle or square Track the Trait… Objective: To demonstrate how to trace a trait through a family tree Bell work: Look at the figure to the right What shape do you think represents a female? A circle What about a male? A square What do you think represents a carrier of a trait? A half shaded circle or square © Getting Nerdy, LLC

Track the Trait… Heterozygous Hybrid Carrier What You Need to Know: A pedigree is a way of tracing a trait through a family tree. Rules for reading a pedigree are as follows: We use specific shapes and shading to signify certain individuals: Affected female = solid circle Affected male = solid square Unaffected female = clear circle Unaffected male = clear square Heterozygous Hybrid Carrier Carrier female = half shaded circle Carrier male = half shaded square © Getting Nerdy, LLC

Track the Trait… I. II. III. We use specific numbers to specify the different generations and the birth order of individuals: Generations (entire lines of individuals) are identified by Roman numerals (I, II, III, IV…). Siblings are placed in birth order from left to right. All individuals are labeled with numbers (1, 2, 3, 4, 5…). I. 1 2 II. 1 2 3 4 5 6 III. 1 2 3 4 5 6 7 We would name a child II-3 if he/she was in the second generation and was the 3rd child. Is the child in position II-3 in the above picture a boy or girl? © Getting Nerdy, LLC

Now, put your knowledge to the test Now, put your knowledge to the test. Complete the following pedigrees on your paper and see if you can Track the Trait! I. II. III. 1 2 3 4 5 6 7 © Getting Nerdy, LLC