Do Now 1. What are mutations?
2. What happens during an insertion mutation?
3. What happens during a deletion mutation?
4. What happens during transcription?
5. What’s a protein?
Announcements Quizzes: I haven’t finished grading them. I’m
sorry, I will get them done ASAP. Gonzaga lost the West Coast Conference
Championship by 4 in OT . ESPN video
Prank calls: These NEED to stop or I’ll be going to the police
and filing harassment charges. I have three numbers of students who have been calling me.
Behavior:
Today INM Phenotype and genotype/ heterozygous
and homogenous Questions 1 – 3 on Bikini Bottom Genetics INM Punnett Squares Questions 4-8 on Bikini Bottom Genetics
What do we need to know to use a Punnett Square? 1. Genotype of parents 2. Which allele is dominant
Phenotype and genotype Phenotype: Physical appearance that
you see Genotype: what the DNA says
IE: Ms. Lusk has brown hair – Phenotype IE: Ms. Lusk’s mom has blonde hair
while her dad has dark hair. Her genotype is actually Bb
Capital letters are the dominant traits These are the ones that you see in a person
phenotype
Purebred = Homozygous Purebred:
Both alleles are for the same trait
Example: FF
Hybrid = Heterozygous Hybrid = The alleles are mixed; they are
for different traits
Example: Ff
Quick Check: Homozygous = stand up, Heterozygous = sit down
BB Homozygous
Bb Heterozygous
bb Homozygous
bB Heterozygous
Probability Have you talked about probability yet in
math? Probability is the extent to which something
could happen. IE: There is a large probability that if you all begin
talking, Ms.Lusk will get upset with you. Flipping a coin results in a 50:50 probability.
I have a 50% chance that if I flip a coin it will land heads.
There’s only two options (heads/tails).
Probability and Genetics In genetics, we use Punnett Squares to
help us understand the probability of something occurring within an offspring.
How are Punnett squares used? A Lot like a multiplication table. Female alleles (genes) are across the
top, and male alleles are down the left side.
R r
R
R
When the female and male alleles are “multiplied,” the result combo of the alleles gives the possible genotypes of the offspring.
RR Rr
RrRR
FIRST: Multiply the two top left columns.
Let’s try a Punnett Square! Hair Color in Humans
B = brown = dominantb = blonde = recessive
DRAW A PUNNETT SQUARE IN YOUR NOTES!!!
Let’s say Kevin Federline and Britney Spears are having a baby…
KFed is heterozygous for brown hair, so….
His genotype is
BbB
b
And Britney is homogenous for blonde hair, so….
Her genotype is
bb
b b
Bb Bb
bb bb
B
b
b b
Bb Bb
bb bb
Genotype Ratio Percentage Phenotype Ratio Percentage
Bb 2/4
2/4 50%50%
Brown Hair
2/450%
bb Blonde Hair
2/4
50%
The likelihood that an offspring will have Brown Hair is ______________ .
The probability that an offspring will have Blonde Hair is ____________ .
***Important*** Probability is the likelihood something will
happen, or the chance that something will happen.
If there is a 25% chance that your kids will have blue eyes, it does not mean that if you have 4 kids one of them is definitely going to have blue eyes!
Guided practice: Widow’s Peak
A recessive gene
W = Normal Hairline
w = Widow’s Peak
Let’s say you have two parents who are heterozygous for the gene
1. What are the chances that their offspring will have a widow’s peak?
2. What are the chances that their offspring will not have a widow’s peak but will carry an allele for a widow’s peak?
3. What are the chances that their offspring will not have a widow’s peak and will not carry a gene for a widow’s peak?
What are their genotypes?
Ww and Ww
Let’s see what happens if the parents have the following genotypes: Ww and ww
1. What are the chances that their offspring will have a widow’s peak?
2. What are the chances that their offspring will not have a widow’s peak but will carry an allele for a widow’s peak?
3. What are the chances that their offspring will not have a widow’s peak and will not carry a gene for a widow’s peak?