Human Phenotype Lab

1
Human Phenotype Lab

• Are you dominant or recessive for each trait?
• What is your genotype and phenotype for each
  trait?

2
Important Concepts

• Remember it takes two copies of the gene.
• Different copies of genes, the letters, are
  called alleles. ex. H or h
• Capital letter dominant (H)
• Lower case letter recessive (h)
• For todays lab, COMPLETE DOMINANCE Big letter
  always wins
• HH or Hh show dominant trait
• hh show recessive trait.
• If Dominant, we dont know your 2nd allele, so
  show a H?
• Genotype is the letters of the genes
• Phenotype is the physical trait (what you see)

3
Right or Left Handed? R? or rr
4
Widows Peak yes or no? W? or ww
5
Mid-digital hair yes or no?M? or mm
6
Dimples yes or no? D? or dd
7
Unattached or Attached Ears? U? or uu
8
Bent or Straight Little Fingers? B? or bb
9
Do you have a blaze yes or no? B? or bb
10
Straight or bent thumb? S? or ss
11
Rolling tongue yes or no? R? or rr
12
Right or Left thumb on top? R? or rr
13
Freckles yes or no? F? or ff
14
Long 2nd toe? Yes or no?L? or ll
15
Which leg crossed on top? Right or left? R? or rr
16
PTC taster yes or no? P? or pp
17
Sodium Benzoate taster yes or no? S? or ss
18
Thiourea taster - Yes or no? T? or tt
19
Question 1

• Does being a dominant trait mean that most people
  have that trait?

20
Question 2

• Is it possible for parents who both have dimples
  to have a biological child who doesnt have
  dimples?
• Prove your answer using the alleles.
• Hint Dimples is a dominant trait.

21
Question 3

• We used a question mark when you had the dominant
  trait because we didnt know your second letter.
• It could have been TT or Tt.
• What could you do in order to determine if your
  second allele is Big or little letter?

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Question 4

• Come up with a way to remember the difference
  between genotype and phenotype.