How many times have you heard from a relative, “You look just like your Uncle Joe?”
Or you might hear, “You’re grandfather had the same nose as you.” It’s obvious to us that traits are passed down from generation to generation. A pedigree is like a map that shows how traits are distributed through a family’s generations.
In this project, you will create two different pedigree charts for at least six members of your own family. You will chart the passing of two different traits for three generations of your family. Clearly indicate and label the traits you are tracing. You will need a key on each pedigree chart. Use the letters below to indicate a particular allele (upper case letters for the dominant allele and lower case letters for the recessive allele). For example, for tongue rolling, use the letter “R” for family members who can roll their tongue and “r” for family members who cannot roll their tongue (use different letters for different traits).
You will need to ask questions of your parents, grandparents, or any other family member included. You can use your creativity in the design of the pedigree chart, but proper pedigree symbols must be used. (See Pedigree
Notes)
I.
II.
Choose 2 traits to investigate in your family
Each pedigree should contain at least 6 people (if you have a small family or several unknowns you will
need to do more than 3 traits – see me for the modifications).
III.
Each pedigree should go back at least 3 generations. (Grandparents, Parents and you)
IV.
Each pedigree should be on an 8.5 x 11 in. piece of paper (no bigger).
V.
Each pedigree should have title on top of the trait being shown.
***Also note for each individual:
A. Genotype (as much as you know, i.e. Tt or T_, or tt)
B. If they have the trait, completely color in their symbol.
Tongue rolling (RR or Rr = roller, rr = non-roller)
Free earlobes (EE or Ee = free , ee = attached)
Mid-digital hair [hair between the first two knuckles] (MM or Mm = hair, mm = no hair)
Hitch-hiker’s thumb (TT or Tt= non-hitch hiker, tt = hitch-hiker)
Widow’s peak (WW or Ww = widow's peak, ww = no widow's peak)
Dimples (DD or Dd = present, dd = no dimples)
Hair texture (HH or Hh = curly, wavy, hh = straight)
Second toe longer than big toe (SS or Ss 2 nd toe longer, ss= big toe longer)
Left over right arm fold (LL or Ll left over right, ll= right over left)
Left over right interlocking fingers (FF or Ff= left over right, ff= right over left)
2 nd finger shorter than 4 th (PP or Pp= 2 nd shorter than 4 th , pp= 2 nd longer than 4 th )
Finally, for the 2 pedigrees you need to answer the following question neatly on the backside of the pedigree paper: If you were to marry a homozygous recessive individual, what is the probability that your offspring would show the trait? You need to show all four steps (including the Punnet square) for full credit.
Please turn this sheet in with your pedigrees
*** Please attach a cover page to your pedigree project and staple this grading rubric as the last page.
Name: __________________________ Period_________
2 Traits analyzed in pedigrees:
________________ _________________
I.
Pedigrees (20 pts)
A.
2 traits investigated in your family (thus, 2 different pedigrees).
B.
Each pedigree should contain at least 6 people.
C.
Each pedigree goes back at least 3 generations.
D.
Each pedigree should be a full 8.5 x 11 inches (no bigger).
E.
Each pedigree should have a key; use appropriate pedigree symbols.
Also note for each individual:
A. Genotype (as much as you know, i.e. Tt or T_)
II.
Probability (6 pts)
A.
Answer the question on backside of the 2 pedigrees for the trait chosen.
1.
Show all 4 steps to answer the question (1. make a key 2. parents in cross 3. Punnet square 4. answer question)
III.
Overall quality of work and effort put forth (4 pts)
Point breakdown:
Topic Possible Earned
1. Pedigrees 20
2. Probability 6
4. Overall 4
Total 30
1.
Tongue Rolling
Generation I: Male- Tongue Roller Female- Tongue roller
Generation II: Male- not a tongue roller Male- Tongue Roller Female- Tongue roller
Marries
Male- not a tongue roller
Generation III: Male- tongue roller Female- tongue roller
2. Dimples
Generation I: Male- Dimples
Generation II:
Female- no dimples
Male: Dimples Male: no dimples Female: Dimples
Marries
Male- Dimples
Generation III: Male- dimples Female- no dimples
EXAMPLE FOR PEDIGREE PROJECT
Trait: 2 nd
toe longer than big toe
Generation I: Male- 2 nd
longer Female- big toe longer
Generation II: Male: 2 nd
longer Male: 2 nd
longer Female: big toe longer
Marries
Male- 2 nd
toe longer
Generation III: Male- 2 nd toe longer Female- big toe longer