Do Now
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2.
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4.
5.
What are mutations?
What happens during an insertion mutation?
What happens during a deletion mutation?
What happens during transcription?
What’s a protein?
Announcements
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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 .
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Prank calls:
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ESPN video
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
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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?
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1. Genotype of parents
2. Which allele is dominant
Phenotype and genotype
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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
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These are the ones that you see in a person phenotype
Purebred = Homozygous
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Purebred:
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Both alleles are for the same trait
Example:
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FF
Hybrid = Heterozygous
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Hybrid = The alleles are mixed; they are for
different traits
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Example:
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Ff
Quick Check:
Homozygous = stand up,
Heterozygous = sit down
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BB
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Bb
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Heterozygous
bb
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Homozygous
Homozygous
bB
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Heterozygous
Probability
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Have you talked about probability yet in math?
Probability is the extent to which something could
happen.
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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.
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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
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In genetics, we use Punnett Squares to help us
understand the probability of something occurring
within an offspring.
How are Punnett squares used?
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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
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When the female and male alleles are “multiplied,”
the result combo of the alleles gives the possible
genotypes of the offspring.
FIRST: Multiply
the two top left
columns.
RR
Rr
RR
Rr
Let’s try a Punnett Square!
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Hair Color in Humans
 B = brown = dominant
 b = blonde = recessive
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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
Bb
B
b
And Britney is homogenous for
blonde hair, so….
Her genotype is
bb
b
b
Bb
Bb
bb
bb
B
b
Genotype
b
b
Bb
Bb
bb
Ratio
bb
Percentage Phenotype
Ratio
Percentage
Bb
2/4
50%
Brown Hair
2/4
50%
bb
2/4
50%
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***
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Probability is the likelihood something will happen, or the
chance that something will happen.
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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
What are their genotypes?
Ww and Ww
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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?
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Let’s see what happens if the parents have
the following genotypes:
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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?