1. Bellwork: Tues. Jan. 9, 2018
Dominant trait: “masks” or covers up recessive traits.
B = brown eyes b= blue eyes Bb = Brown eyes
Recessive trait: will only appear without dominants.
bb = blue eyes
Remember: Dominant traits: capitalized ( B, T, F…)
Recessive traits: lower case ( b, t, f…)

2. 3. Genotype:___________ makeup of an organism.
(“the letters”)
Phenotype:_____________ appearance of an organism.
Homozygous: ___________________________
Heterozygous: ___________________________
Allele: _________ __________ of a gene.

3. Human Traits Lab Dimples are dominant Cleft chin is dominant
Wet ear wax is dominant…
I have the recessive “dry”
ear wax

4. Human Traits Lab Dimples are dominant Cleft chin is dominant
Wet ear wax is dominant…
I have the recessive “dry”
ear wax

5. Crash course biology

6. What is dominant? What is recessive?
A trait that is considered “dominant” masks recessive traits. In other words, it “dominates” the recessive.
A recessive trait requires no dominant traits to be present. These recessive traits will only appear without dominants.
Dominant traits are capitalized (IE: A, X, F, etc)
Recessive traits are lower case (IE: a, x, f, etc)

7. So dominant does not mean more common 
…So having dimples, and a
cleft chin is rare because
the versions of these genes
are rare. And as long as there
is no advantage or disadvantage
to having dimples, then the
relative amounts of people with
dimples won't change over time
in a stable population.
Dimples are dominant yet rare because the dimple gene version is rare…
the same goes for
cleft chin…
So dominant does not mean more common 
Dominant just means that form of the trait will
“win out” over the recessive form.
But… if the form of the gene is advantageous to a population, more
Individuals with than form will survive to pass on that gene to their offspring. So for some other genes it seems like almost everyone
has that dominant trait….

8. Tasters in class:
Non-tasters in class:
Total:
Percent tasters:

9. Accidental Taster in 1931
Chemist Arthur Fox sat at his DuPont Company lab bench, mixing a powdered chemical. Accidentally a bit of the powder blew into the air. Fox and another scientist got some of the chemical into their mouths. Dr. Fox's colleague exclaimed how bitter the powder tasted. Fox was surprised -- he had been much closer to the chemical, but he tasted nothing at all.

10. Both men tasted the chemical again
Both men tasted the chemical again. To Fox it was still tasteless, but his co-worker insisted it was very bitter. Fox handed out crystals of the chemical, which were not poisonous, to his friends, family members and fellow scientists and asked them if they tasted anything.
Some people, like Fox, tasted nothing; others found the chemical somewhat bitter or intensely bitter.
What was going on?

11. Since then, the chemical phenylthiocarbamide (PTC) has been used to detect genetic variation in tasting abilities. Studies soon after the incident in Fox's lab showed that there is a genetic component that influences how PTC tastes!
Scientists found that people were much more likely to find PTC bitter if other members of their family also found it bitter.
The evidence was so strong for a genetic
link that PTC tasting ability was used as
evidence in paternity tests before DNA
tests were available!

12. About 70% of people can taste PTC
Dominant/recessive trait in humans…
taste = dominant allele “T” for the gene
Cannot taste = recessive allele “t”.
But since you get an “allele” (gene) from each parent… if you can taste the PTC you COULD be either TT or Tt
If you cannot taste the PTC then you are tt…
If you listen and “get” this concept NOW the weeks after break will be a lot easier AND you can compare traits with relatives during break.

13. TT or Tt tt taste can’t taste

14. http://www. telegraph. co

15. Phenotype: physical appearance/ WHAT the trait “causes”.
Some Terms:
Phenotype: physical appearance/ WHAT the trait “causes”.
YOU CAN OBSERVE phenotypic traits: Eye color, hair color height, nose shape eye shape…:
In this lab, you will determine some of your own phenotypic traits and figure out some of your possible genotype(s) for these traits. 

16. You only need one copy of a dominant gene in order to see a dominant phenotypic trait, but you need two copies of a recessive gene in order to see a recessive phenotypic trait.  
A dominant phenotypic trait is represented capitol letter  like B for brown eyes
A recessive phenotypic trait is represented lower case letter  like b for blue (or light color) eyes
BB =
Bb =
bb =
You must have two recessives to “exhibit” (show) the recessive trait

17. Your Genotype (gene make-up) “letters” can be:
homozygous dominant: BB, (phenotype: brown) or
homozygous recessive: bb , (phenotype: blue)
Heterozygous Bb (phenotype: brown)
…write the capital letter first

18. Incomplete dominance is a special case when the heterozygous (BIG LETTER, little letter – Bb) phenotype “mixes” (or is intermediate), and not DOMINATED by dominant gene. 
 Snapdragon flowers are an example of this: , homozygous dominant flowers are red homozygous recessive flowers are white, and heterozygous flowers are pink. 

20. Hairline: A widow’s peak (W) hairline comes to a point in the center of the forehead. It is dominant trait (genotype can be WW or Ww) to having a straight hairline (w) has to be ww).

22. Eye shape:  Almond-shaped eyes are dominant (A) to round-shaped eyes (aa).
round shaped eyes (a) almond shaped eyes (A) (notice the white visible under the iris)

23. Eyelash length:  Long eyelashes are dominant (E) to short eyelashes (e).
Short eyelashes (e) ee long eyelashes (E) so EE or Ee

24. Tongue-rolling:  The ability to roll the tongue is dominant (C) to the inability to roll the tongue (c). 
Can roll tongue (C) so CC or Cc Can’t roll tongue (c) cc

26. Thumb:  The hitchhiker’s thumb (thumb tip bends backward more than 30 degrees) is dominant (B) to a straight thumb (b).
Straight thumb (mine) (b) I’m bb
Hitchhiker’s thumb (B) so… BB or Bb

28. Lip Thickness: Thick lips are dominant (L) to thin lips (l).
Thick lips (L) so… LL or Ll Thin lips (l) have to be ll

29. Hair Texture:  Curly hair is incompletely dominant (HH) to straight hair (SS).  Those who have wavy hair are intermediate (HS).
Curly Hair HH Wavy Hair HS Straight Hair SS

30. Inter-eye Distance:  Close-set eyes are incompletely dominant (DD) to eyes set far apart (FF).  Medium-set eyes are DF.
Close set eyes: DD
Wide set eyes FF

31. Lip Protrusion:  Protruding lips are incompletely dominant (PP) to nonprotruding lips (NN). Slightly protruding lips are intermediate (PN).
Protruding lips PP slightly protruding lips PN nonprotruding lips NN

32. X X X X Trait Your Phenotype Possible Genotype(s) Hairline W w
      Check only one:
Trait
Your Phenotype
Possible Genotype(s)
Dominant
Recessive
Intermediate
Hairline
W w  X
Eye Shape
A a
  X
Eyelash Length
E e
  X
Tongue Dexterity
C c X
Thumb
B b
Lip Thickness
L l
Hair Texture
H / S
Inter-Eye Distance
D / F
Lip Protrusion
P / N

33. Hairline: A widow’s peak (W) hairline comes to a point in the center of the forehead. It is dominant trait (genotype can be WW or Ww) to having a straight hairline (w) has to be ww). Eye shape: Almond-shaped eyes are dominant (A) to round-shaped eyes (aa). Eyelash length: Long eyelashes are dominant (E) to short eyelashes (e). Tongue-rolling: The ability to roll the tongue is dominant (C) to the inability to roll the tongue (c). Thumb: The hitchhiker’s thumb (thumb tip bends backward more than 30 degrees) is dominant (B) to a straight thumb (b). Lip Thickness: Thick lips are dominant (L) to thin lips (l). Hair Texture: Curly hair is incompletely dominant (HH) to straight hair (SS). Those who have wavy hair are intermediate (HS). Inter-eye Distance: Close-set eyes are incompletely dominant (DD) to eyes set far apart (FF). Medium-set eyes are DF. Lip Protrusion: Protruding lips are incompletely dominant (PP) to nonprotruding lips (NN). Slightly protruding lips are intermediate (PN).

34. Hairline Eye Shape Eyelash Length Thumb Lip Thickness Hair Texture
      Check only one:
Trait
Your Phenotype
Possible Genotype(s)
Dominant
Recessive
Intermediate
Hairline
(widow’s/straight)
Eye Shape
Almond/round
Eyelash Length
Long/short
Tongue Dexterity
Roll/not roll
Thumb
Lip Thickness
Hair Texture
Inter-Eye Distance
Lip Protrusion

35. Answer the questions and turn in
1.  Which traits do you have that are dominant? (list them) 
2.  Which traits do you have that are recessive? (list them)
3.  Which of your traits are incompletely dominant (mixed)? 
4.  Which of your traits do you share with one or more of your classmates?
5.  What determines your traits (i.e., how do you acquire them)?  
 6. Which traits are more common (dominant or recessive)? Why?

36. Tues. Jan
End

37. Bellwork: Tues. Dec. 1, 2015
Name the independent variable and dependent variable the two experiments.
1. I.V: _____ D.V.: _____
2. I.V: _____ D.V.: ______

38. https://www.youtube.com/watch?v=mnSkz8s-b44 Smooth Axial Constricted
Terminal

42. Bellwork: Wed. Jan. 7, 2013
In seals, the gene for whisker length is controlled by 1 gene. The dominant allele (W) = long whiskers
the recessive allele (w) = short whiskers.
If a homozygous dominate male seal and homozygous recessive female seal mate, what is the probability that their pups will have long whiskers? Draw a Punnett Square & show the cross:
______ X ______ and show the:
genotypic ratio:______:______
phenotypic ratio:_____:______ 42