Transcript sponge bob square

Genetics
How do traits pass from parents to
offspring?
Genetics Unit
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• Create a vocabulary sheet. Through-out
these notes, write any “red” vocabulary
words and their definitions on this page.
Vocabulary Word
1.
2.
Definition:
DNA  Chromosomes
• From Chromosome to DNA
• How DNA is packaged animation
• Meiosis is how DNA is copied and
sepereted to make gametes (sperm and egg)
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• Complete cornell notes for the Meiosis
video (bozeman…goes quick…)
• What is the purpose of Meiosis and
Mitosis?
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Complete the lab “Why don’t we
look like our siblings”
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Chromosome set
Female Set
Male Set
Female vs Male set
Similarities
Differences
Inheritance
Gregor Mendel – “Father of Genetics”
• Did experiments with pea plants in mid-late
1800’s to show basic patterns of inheritance
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Seed Shape
Seed Color
Seed Coat color
Pod Shape
Pod Color
Flower Position
Plant Height
Traits
(round or wrinkled)
(yellow or green)
(gray or white)
(smooth or constricted)
(green or yellow)
(axial or terminal)
(tall or short)
Alleles
Dominant Recessive
Alleles
Alleles
Found that when two plants
with different alleles are
crossed, the offspring look
like one of the parents, rather
than a blending of both
parents.
Principle of Dominance
Some alleles are dominant
and others are recessive
Summary of Mendel’s Principles
Phenotype song
Gregor Mendel’s work forms the basis of modern genetics:
• Genes are passed from parent to offspring
• Some forms of genes (alleles) are dominant while others are recessive
• Genes randomly segregate (independent assortment) when gametes are formed
• The alleles for different genes usually segregate independently of one another
Linked genes (genes that occur very close
to one another on a chromosome) are the
exception
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Write these 4
ideas from
Mendel
Inheritance: the passing of traits
from parents to offspring
Gregor Mendel – “Father of Genetics”
• Phenotype - The observable physical characteristic of a trait
• Genotype - The genetic combination of alleles for a trait
• Punnett Square – tool used to predict probability of phenotype
Phenotype: White
Genotype: pp
Phenotype: Purple
Genotype: PP
Notice that letters are used to represent the
alleles (usually correspond to the dominant
phenotype – e.g. “P” for purple)
Upper Case Letters = Dominant Allele
Lower Case Letters = Recessive Allele
Practice
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• Overview of genes to traits video
• Copy the 3 questions below:
• What do they mean when they say “you
have your father’s hair”?
• How many chromosomes do organisms
have?
• How much DNA do we have in common
with other animals?
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• Complete the “Just Like Me” lab.
Just like Me
Widow’s Peak (P)
No Widows peak (p)
Just Like Me
Dimples (D)
No Dimples (d)
Just Like Me
Freckles (F)
No Freckles (f)
Just Like Me
PTC Taster (J)
PTC nontaster (j)
Just Like Me
Hand cross
Right thumb on top (A)
Hand cross
Left thumb on top (a)
Just Like Me
“Bent” Little fingers (B)
Parallel little fingers (b)
Just Like Me
Tongue roller (T)
Non-tongue roller (t)
Just Like Me
Hair on fingers (H)
No hair on fingers (h)
Just Like Me
Attached ear lobe (e)
Free ear lobe (unattached)
(E)
Just Like Me
Cleft (dimpled) chin (C)
No cleft chin (c)
Just Like Me
PREDICTION
• For each trait, make a
prediction about what
percentage of your
classmates are “like you”
for each trait.
Just Like Me
results
• Go to your teachers website
• Click on the phenotype
survey link
• Fill in your results
• Use the “form” button on
the top menu bar to show
the class results
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finish
• Fill in the chart on your
paper
• Make a bar graph of the
results
• Answer all the questions
Inheritance
Gregor Mendel – “Father of Genetics”
• Found that alleles show up in predictable patterns and
that some alleles show up more often than others
• Homozygous (Pure-Breeds) - both alleles are the same
• Heterozygous (Hybrids) - both alleles are different
• Carriers – heterozygotes for a recessive trait
Pure-Breed Crosses result in:
100% chance dominant phenotype
Hybrid Crosses result in:
75% chance dominant phenotype
25% chance recessive phenotype
Inheritance
Gregor Mendel – “Father of Genetics”
• Found that alleles show up in predictable patterns and
that some alleles show up more often than others
• Alleles can be tracked through multiple generations
and probabilities determined
Parents: P1 generation
First Generation: First Filial (F1)
100% chance dominant phenotype
Second Generation: Second Filial
(F2)
75% chance dominant phenotype
100% chance
75% chance
75% chance
0% chance
Third Generation: Third Filial (F3)
63% chance dominant phenotype
Practice
• Dominant vs Recessive genes video
• Video on making punnett squares
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Solving Punnett Squares :
If a round pea plant (AA) is crossed
with a wrinkled pea plant (aa), what
percent of the offspring will be:
• Round?
• Wrinkled?
If two heterozygous round pea
plants are crossed, what percent of
the offspring will be:
• Round?
• Wrinkled?
If a heterozygous round pea plant is crossed
with a homozygous wrinkled pea plant, what
percent of the offspring will be:
• Round?
• Wrinkled?
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• Complete the Probability Lab
(Long vs Short Big Toe)
Phenotypic Expression Varies
• Complete Dominance:
 Homozygous dominant genotype  dominant phenotype
 Heterozygous genotype  dominant phenotype
 Homozygous recessive genotype  recessive phenotype
• Codominance
• Incomplete Dominance
• Sex-Linked
• Polygenic Traits
Complete dominance
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p86
1. Which of the following are genotypes and which
are phenotypes:
Brown hair
Homozygous recessive
Bb
Webbed Fingers
Hybrid
Down Syndrome
2. If two individuals mate and their child has a
phenotype completely different from both parents,
what was the genotype of the parents?
Practice
• Sponge Bob Genetics
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Phenotypic Expression Varies
• Complete Dominance
• Codominance
 Homozygous genotype  one phenotype
 Heterozygous genotype  both phenotypes
• Incomplete Dominance
• Sex-Linked
• Polygenic Traits
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Codominance
• If two alleles are codominant and two
heterozygous (spotted RW) flowers mate,
what percentage of the offspring will have
white flowers (WW) and what percentage
will have red flowers (RR)?
Phenotypic Expression Varies
• Complete Dominance
• Codominance
 Homozygous genotype  one phenotype
 Heterozygous genotype  both phenotypes
• Incomplete Dominance
• Sex-Linked
• Polygenic Traits
R
R
W
RW
RW
W
RW
RW
R1
R1
R2
R1R2
R1R2
R2
R1R2
R1R2
Practice
• Intro to blood types (first 3 minutes good)
• Complete blood typing handout
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Blood type of
parents
A and O
B and O
A and B
AB and A
AB and B
AB and O
O and O
All possible
genotypes of
parent
All possible
genotypes of
children
All possible
blood types of
children
Blood types
not possible for
children
Phenotypic Expression Varies
• Complete Dominance
• Codominance
• Incomplete Dominance
 Homozygous genotype  one phenotype
 Heterozygous genotype  new phenotype
• Sex-Linked
• Polygenic Traits
• Complete Dominance
• Codominance
• Incomplete Dominance
• Sex-Linked
 X-linked: gene lies on X chromosome (males only have one copy of
the gene)
 Y-linked: gene lies on Y chromosome (only males have the gene)
 Contributes to younger mortality rate in males
• Polygenic Traits
Practice
• Pipe Cleaner babies and genetic traits”.
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Hemophilia
Hemophilia
Hemophilia
• X-linked Inheritance worksheet
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Solving Punnett Squares
Predicting phenotype gets more
complicated when you look at more
than one trait at a time
Parents
Depending on how the
chromosomes independently
assort determines the
genotype, and thus
phenotype, of the resulting
progeny (offspring)
Offspring
Solving Punnett Squares:
If a round, yellow pea plant (AABB)
is crossed with a wrinkled, green
pea plant (aabb), what percent of
the offspring will be:
• Round and yellow?
• Round and green?
• Wrinkled and yellow?
• Wrinkled and green?
What about the F2 generation?
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Practice
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• Dihybrid Crosses handout (bunny rabbits).
And Sponge Bob II
Pedigree Rules
• What is a pedigree?
• *A pedigree is a chart that shows all
family members and how they are
related. It follows certain rules and
shows genotypes and phenotypes.
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– Boys
– Girls
Shaded- Phenotype
being “traced”
X
deceased
Marriage
same level=same
generation
Mating w/o marriage
Carrier
(heterozygous)
Kids
Adopted
Twins
• Draw a pedigree for your immediate
family (mom, dad, step parents, siblings,
etc)
More Practice
• Pedigree project
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Widow’s Peak (P)
No Widow’s Peak (p)
Dimples (D)
No Dimples (d)
Freckles (F)
No Freckles (f)
PTC Taster (J)
PTC non-taster (j)
Hand cross –
Right thumb on top (A)
Left thumb on top (a)
Bent little fingers (B)
Parallel little fingers (b)
Tongue Roller (T)
Non-tongue roller (t)
Hair on fingers (H)
No hair on fingers (h)
Free ear lobes (E)
Attached ear lobes (e)
Cleft chin (C)
No cleft chin (c)
Pedigrees
• Graphically shows the lineage of
a disorder in a particular family
• Be able to tell if disorder is
dominant, recessive, or sexlinked from a pedigree
• Be able to predict the chance
that an indicated couple will
have a child with the disorder
Autosomal Dominant Pedigree
How can we tell?
Pedigrees
• Graphically shows the lineage of
a disorder in a particular family
• Be able to tell if disorder is
dominant, recessive, or sexlinked from a pedigree
• Be able to predict the chance
that an indicated couple will
have a child with the disorder
Autosomal Recessive Pedigree
How can we tell?
Pedigrees
• Graphically shows the lineage of
a disorder in a particular family
• Be able to tell if disorder is
dominant, recessive, or sexlinked from a pedigree
• Be able to predict the chance
that an indicated couple will
have a child with the disorder
Sex-Linked Pedigrees
How can we tell?
Is the X-linked dominant or recessive?
Pedigree Analysis Case Study
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Read family information
Put family name at the top of your whiteboard
Make a pedigree for the entire family
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Place name of condition under family name
Label names of all family members that you know
Make a key for the possible genotypes and phenotypes of your trait. Label as many
individual genotypes on the pedigree that you can.
Shade in the people that have the trait
Identify the Patterns in the Pedigree and write the answers on your whiteboard:
Does the trait:
– show up in every generation?
– Or, does the trait skip a generation?
Is the trait dominant or recessive?
Gender:
– Does the trait affect males/females equally?
– Or, Does the trait only affect males? Or, only females?
Does your trait fit one of the patterns we have learned so far (complete dominance,
codominance, incomplete dominance, or X-linked)? If so, which one? How do you
know?
More Practice
• Hooded Murderer
Karyotypes
• Complete the karyotype webquest
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More practice:
• Oompa Loompa Genetics
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Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Step 1: Fill in Table of Alleles for your
paper bag pet that reflect its genotype for
each trait . Note that Tail and Eyelashes
are X-Linked!
TRAIT
Sex
Nose Shape
Eye Shape
Ear Shape
Hair Color
Eye Color
Eyelashes
Tail
SYMBOLS FOR EACH ALLELE
PHENOTYPE
XX or XY
Circle (N), Triangle (n)
Slit (E), Oval (e)
Round (R), Pointed (r)
Black (H), Brown (h), yellow (y)
Brown (B), Blue (b), green (g),
yellow (y)
Eyelashes (L), No Eyelashes (l) Xlinked!
Tail (T), No Tail (t) On Y
chromosome- only males can
have a tail!
GENOTYPE
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Step 2: Decorate a “pet” paper bag with traits that
adhere to this given set of phenotype choices: Cut off the bottom
1” from the paper bag. Use this strip to make arms and other body
parts.
Gender
male or female?
Tail
tail or no tail? (females cannot have tails)
Eye Shape
round or oval (almond) shaped?
Eye Color
brown, blue, green, yellow?
Eyelashes
has eyelashes or is lashless?
Nose Shape
circular or triangular?
Hair Color
black, brown, or yellow?
Ear Shape
round or pointed?
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Step 3: Create chromosomes for your paper bag
pet that reflect its genotype for each trait
For Females
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Create chromosomes for your paper bag
pet that reflect its genotype for each trait
For Males
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Step 4: Create gametes for your pet paper bag
Step 1: DNA replication
For Females
For Males
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Create gametes for your pet paper bag
Step 2:
Crossing Over
Step 3:
Random
Assortment
Step 4:
First cell division
Random assortment
Crossing Over
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Create gametes for your pet paper bag
Step 5:
Second cell
division
• STEP 5:
• Carefully cut out the parent chromosomes
and glue them onto the back side of your
parent bag (these are the DARK
chromosomes).
• Also cut and glue the parent table of alleles
to the bag.
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Step 6: Find a mate and procreate!
Trade one autosome and one sex
chromosome with someone else. These
are your child’s chromosomes. Glue
them onto the back of a new bag.
• Step 7:
Fill out a table of
alleles for your child from the
child’s chromosomes.
– Glue the table onto your new
paper bag next to the
chromosomes.
• Step 8:
decorate
• your child.
• Step 9:
Fill out a birth
certificate for your child.
Mom
Child
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Step 10: Fill out the Punnett Square Worksheet
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Fill out the Punnett Square Worksheet
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Fill out the Punnett Square Worksheet
Mom
Child
The
End
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
1.
Fill in Table of Alleles and create chromosomes for your paper bag pet
that reflect its genotype for each trait
2.
Decorate a “pet” paper bag with traits that adhere to a given set of
phenotype choices
3.
Create gametes for your pet paper bag
4.
Find a mate and procreate
5.
Fill out the Punnett square worksheet to predict the traits of your
offspring
6.
Give birth: decorate your baby bag with phenotypes that match its
genotypes and fill out the birth certificate
Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project
Method 1: Culminating Project
Day 1
Decorate a “pet” paper bag with traits that adhere to a given
set of phenotype choices
Day 2
Create chromosomes for your paper bag pet that reflect its
genotype for each trait (use rest of period to introduce or
reinforce meiosis)
Day 3
Create gametes for your pet paper bag
Day 3
Find a mate and procreate
Day 4
Fill out the Punnett square worksheet to predict the traits of
your offspring (first introduce or reinforce Mendelian genetics)
Day 5
Give birth: decorate your baby bag with phenotypes that
match its genotypes and fill out the birth certificate
Animations
Mitosis vs Meiosis
http://www.johnkyrk.com/meiosis.html
http://www.pbs.org/wgbh/nova/baby/divi_flash.html
http://www.cellsalive.com/meiosis.htm
Nova Videos
Cracking the Code of Life: http://www.pbs.org/wgbh/nova/genome/program.html
Miracle of Life: http://www.pbs.org/wgbh/nova/miracle/program.html
Tay Sachs (one wrong letter)
http://www.pbs.org/wgbh/nova/genome/program.html
Practice Problems
1. How do mutations during meiosis affect an organism differently than mutations
during mitosis?
2. At each step of meiosis, is the cell haploid or diploid?
3. Which of the following are genotypes and which are phenotypes:
Brown hair
Hybrid
Bb
Webbed Fingers
Homozygous recessive
Down Syndrome
4.
If an allele is dominant and two heterozygous individuals mate, what is the
chance that their child will have the dominant phenotype?
5.
If two alleles are codominant and two heterozygous individuals mate, what is
the chance that their child will have both phenotypes?
6.
If two individuals mate and their child has a phenotype completely different
from both parents, what was the genotype of the parents?
7.
If a disorder is X-linked and a normal man mates with a woman who is a
carrier, what is the chance that they will have a boy with the disorder? What is
the chance that they will have a girl with the disorder?
Practice Problems
8.
If a woman is homozygous recessive for both blonde hair and blue eyes and
she mates with a man who is heterozygous for both brown hair and brown
eyes, what is the chance that their child will have blonde hair and blue eyes?
9.
In real life, eye color and hair color are actually polygenic in humans. What
does this mean?
10. If a person with type A blood mates with a person with type AB blood, what is
the chance that they will have a child with:
• type A blood?
• type B blood?
• type AB blood?
11. If a person with type O blood mates with a person with type AB blood, what is
the chance that they will have a child with:
• type O blood?
• type A blood?
• type AB blood?
• type B blood?
Practice Problems
12. In the pedigree, which individuals are affected males? Affected females?
Normal males? Normal females?
13. Which type of inheritance is indicated by the pedigree below?
14. Which individuals are homozygous recessive in the pedigree?
15. Which individuals are homozygous dominant in the pedigree?
16. Which individuals are heterozygous in the pedigree?
17. If the top two individuals in the pedigree had another baby,
what are the chances that he/she would
have the disorder?
Practice Questions
1.
Which regulatory mechanisms occur at the DNA-level, which occur at the
protein-level?
2.
How do acetylation, methylation, repressors, activators, and siRNA control
gene expression? What role do inducers play?
3.
What is an enhancer and how does it help control how much of a particular
protein is made?
4.
How do allosteric inhibition and competitive inhibition differ in the ways they
accomplish feedback inhibition?
5.
What are the three phases of the cell cycle? What occurs at each phase?
6.
What are the four phases of mitosis? What occurs at each phase?
7.
What are cell cycle checkpoints? Why are they important?
8.
What is apoptosis? What role does it play in the cell cycle?
9.
What is the difference between chromatin and chromosomes?
10. What is the role of the centromere? (What would happen without it?)
Practice Questions
11. What is the difference between a chromatid and a chromosome?
12. What events must happen in order for two sister chromatids to separate from
one another and move to opposite sides of the cell? (What happens at the
centromere? What happens to the centromere? What is the role of the mitotic
spindle?)
13. What would happen if two sister chromatids moved to the same side of the
cell?
14. What happens to the mitotic spindle after mitosis?
15. What are gametes? Where are they made in the body? How are they made?
16. What are the eight phases of meiosis? What occurs during each phase? How
does meiosis differ from mitosis?
17. How do crossing over and random assortment “mix up” genes so that
children are genetically different from their parents?
18. Why are insertion and deletion mutations usually more harmful than
substitution mutations?
Practice Questions
19. How does nondisjunction affect the genes present in an organism?
Specifically, why does it cause deformities?
20. What “super powers” must a cell acquire to become cancerous? How does it
acquire these powers?
21. Compare and contrast oncogenes and tumor suppressor genes. What are they?
How are they similar? How are they different?
22. Why is cancer primarily a disease of old age?
23. How do mutations cause genetic variation? Is this good or bad for the
organism?
24. How do genetic diseases caused by point mutations differ from those caused
by chromosomal mutations like nondisjunction?
25. What causes spontaneous mutations? What causes induced mutations?
26. How accurate is DNA replication? (That is, how often do point mutations
occur?)
27. What type of mutation is shown here? AGTGCCGTCAC
TCACGGCCAGTG
Practice Questions
28.
Why is DNA synthesis said to be “semiconservative”?
29.
What role do DNA polymerase, DNA primase (a type of RNA polymerase),
helicase, topoisomerase, RNase H, and ligase play in DNA replication?
30.
What is the difference between how the leading strand and lagging strand are
copied during DNA replication? Why do they have to be synthesized
differently in this fashion?
31.
What would happen if insufficient RNase H were produced by a cell? What if
insufficient ligase were produced by a cell?
32.
What are four key differences between DNA polymerase and RNA
polymerase? (“they are difference molecules” doesn’t count as one!)
33.
Compare and contrast codons and anticodons?
34.
What is alternative splicing? Why is it necessary in eukaryotes?
35.
During translation, what amino acid sequence would the following mRNA
segment be converted into: AUGGACAUUGAACCG?
36.
How come there are only 20 amino acids when there are 64 different codons?
37.
How come prokaryotes can both transcribe and translate a gene at the same
time, but eukaryotes cannot?
Sources of Genetic Diversity
During Interphase (DNA Replication)
• Mutations – create new alleles
During Meiosis
• Random Assortment (Independent Alignment) – mixes up
chromosomes inherited from mother and father
• Crossing Over – mixes up genes that occur on the same
chromosome
(“Linked genes” occur adjacent or very close to one another on the same
chromosome and so are almost always inherited together)
During Sex
• Fertilization – mixes up genes from two different partners
Genetic
Disorders
Inherited
New Mutations (“De Novo”)
(from mom or dad or both)
(new point mutations or chromosomal)
Complete Dominance
Incomplete Dominance
Codominance
Sex-Linked
Polygenic Traits
meiosis
Gametes
(egg / sperm)
Tay Sachs (one wrong letter)
http://www.pbs.org/wgbh/nova/genome/program.html
Variations in Heritability
Qualitative Traits
• controlled by a single gene
• Clearly have a defined phenotype
• Ex: attached ears or lobed ears
Qualitative Traits
• Controlled by multiple genes (polygenic)
• Influenced by the environment
• Shows a gradation of phenotypes
• Ex: height
Polymerase Chain Reaction (PCR)
Method used to copy DNA
1. Strands are “melted” apart
using heat
2. Primers and nucleotides
(NTP’s) are added and the mix
is gradually cooled
3. Results in formation
of complementary
strands
4. Cycle is repeated,
doubling number
of DNA strands
each time
http://www.dnalc.org/ddnalc/resources/pcr.html
http://www.sumanasinc.com/webcontent/animations/content/pcr.html
Phenotypic Expression Varies
• Complete Dominance
• Codominance
• Incomplete Dominance
• Sex-Linked
• Polygenic Traits
 Controlled by more than
one gene
 Most common type of
expression