Transcript 3. Multiple Allele Traits

Fri 2/8
• Test-Chp.9 today
• INB Check 2
• Chp.12 Title Page
Pg.35
Title page for chp.12
• Chp. title
• 3 pictures—having to do with topic of chp.
• 3 colors
• 3 key words
Mon 2/10
• Objective: Investigate patterns of
human inheritance.
• Cornell Notes – Human Inheritance
• 3-Column Vocabulary
In: pg 36
Scientists often refer to Mendelian genetics.
What are 3 rules Mendelian genetics
must follow?
1.
2.
3.
Mendel’s Conclusions (Review)
1. Recessive and Dominant factors
• 1 trait always shows up if present (dominant)
• 1 trait can be hidden by the dominant factor
(recessive)
2. Law of Segregation-each parent has 2 factors
for each characteristic. They only give one of
these factors to each offspring.
3. Law of Independent Assortment-each parent
has many characteristics to pass on to each
offspring. The inheritance of one characteristic
doesn’t affect the inheritance of a different
characteristic.
Pg.37 – Set up Cornell Notes
Chp.12-Inheritance Patterns
& Human Genetics
• Karyotype-picture of all the
chromosomes of an
individual.
• Humans have 23 pairs of
homologous chromosomes.
– Autosomes
• Pairs 1-22
– Sex Chromosomes
• Pair 23
• Determine your gender
• Males=XY
Females=XX
• Eggs only carry the X
chromosomes, sperm carry
X or Y.
Human Karyotype
Down’s Syndrome-Trisomy 21
Klinefelter’s = XXY
Simple vs. Complex Inheritance
• Simple inheritance is like
Mendel’s experiments—2
alleles, one dominant and
one recessive.
– Often called Mendelian
inheritance.
• The inheritance of one trait
doesn’t effect the inheritance
of another trait
• Complex patterns of
inheritance do not follow this
pattern.
Types of Complex Inheritance
1.
2.
3.
4.
5.
6.
7.
Incomplete and codominance
Polygenic traits
Multiple allele traits
Complex characters
Sex Influenced traits
Linked genes
Sex-linked traits
Remember: these do not follow
Mendelian inheritance!!!
1. Incomplete and codominance
•
Incompleteheterozygotes have a
blend of the 2 alleles.
–
–
–
–
•
Tay Sachs disease
TT=normal production
of lipid metabolizing
enzyme.
tt=no enzyme
Tt=1/2 of the needed
amount of enzyme
Codominance-both
alleles show up in
heterozygotes.
–
Sickle cell anemia
2. Polygenic traits
• Polygenic traits are
controlled by more
than one gene
pair.
• Such traits
produce a bellshaped curve.
– In humans, these
include height, skin
color and hair
color.
3. Multiple Allele Traits
• Multiple alleles-when more than two
different alleles exist for a trait.
• Example: Human Blood Type
– Has 3 possible alleles (A,B,O)
– A person only gets 2 of these alleles.
•
•
•
•
•
•
A and B are codominant.
O is recessive to A and B
AA/Ao=type A
AB=type AB
BB/Bo=type B
oo=type O
Inheritance of blood type
IB
io
IA
IAIB
IAio
IB
IBIB
IBio
4. Complex characters
• Influenced by
environment and
genes.
– Cancer, skin color,
height
5. Sex Influenced traits
• Males and females show a different
phenotype when they have the same
genotype.
– Male pattern baldness
6. Linked traits
• Traits that tend to be inherited
together because they are close
together on the chromosome.
7. Sex-linked traits
• Autosomal genes-found on the autosomes(1-22)
• Sex-linked genes-Genes carried on the X or Y
chromosome (Pair 23).
– These genes code for sex-linked traits.
– X-linked traits are more common than Y-linked traits
(the X chromosome is much larger)
– Males get X-linked traits more commonly than
females because they have only one X chromosome.
Recessives are NOT hidden.
Human sex-linked traits
• Human sex-linked
diseases include
colorblindness and
hemophilia.
Red-green colorblindness
• Recessive trait carried
on the X chromosome.
• XR=normal vision
• Xr=red-green colorblind
Females: XRXR XRXr XrXr
Males:
YXR
YXr
Finish Cornell Notes
• 3 questions in left column
• 3 sentence summary at bottom
Pg.38-39 – Chp.12 3-Column Vocab
1.Autosome
2. Sex chromosome
3.Sex-linked trait
4.Linked gene
5.Complex character
6.Polygenic
7.Multiple allele
8.Karyotype
9. Incomplete
dominance
10. Codominance
11. Genetic disorder
Homework
• Finish 3 column vocab.
– Due on Wed!!!!
Out pg.36
• Why are the topics we are studying in
this chapter not considered
“Mendelian Genetics”?
Male pattern baldness is not “Mendelian Genetics”
Tues 2/11
• Investigate patterns of human inheritance.
In: pg.40
• Complete the critter diagram
Exceptions to Mendelian
Inheritance
Pg.41: Hand Span Lab—Determining
Polygenic Inheritance
• Your hand span = ____cm.
• Complete class data on board
• Data: Create a bar graph & glue in
• Analysis Questions:
1. What does polygenic mean?
2. What should a graph of a polygenic
trait look like?
3. How can you tell that a trait is
polygenic based on phenotype?
Out – pg.40
• What are 3 human traits besides hand
span that are polygenic?
Wed 2/12
• Investigate patterns of human inheritance.
In: pg.42
Why are X-linked
traits often called
male diseases?
Morgan’s Experiment-1910
• Discovered sexlinkage.
• Drosophila
• White eyes appeared
mostly in males.
• XR= red eyes
Xr=white eyes.
• Females=XRXR, XRXr,
XrXr
• Males=XRY, XrY
Pg.43
• Sex Linked Group Practice
– Complete and glue in booklet
Pg.44: Gene Spy
• Glue in as a flip
and complete
Pg.45: Who gets
the money?
Glue in booklet and
complete
Homework
• Finish Gene Spy and Who gets the money?
Out – pg.42
Color blindness is an X-linked recessive
trait. Xb=color blind
1. Is it impossible for a woman to be color
blind?
2. Give a specific example to support your
answer!
Thur 2/13 & Tues 2/18
• Discuss various techniques for diagnosing
genetic disorders.
In: pg.46
Look at the karyotype below.
• What are 3 “rules” for organizing
chromosomes into a karyotype?
1.
2.
3.
Pg.47
The Sticky Situation
Down’s Syndrome-Trisomy 21
Klinefelter’s = XXY
Pg.48 - Analysis Questions
1. What is the the abnormality in this
karyotype?
2. What genetic disorder does this
chromosomal abnormality cause?
3. What are the symptoms of this
genetic disorder?
4. An abnormal # of chromosomes
is normally caused by non
disjunction. How does it cause
an abnormal # of chromosomes?
5. Why do you think that Down’s
syndrome is also called “Trisomy
21”?
6. What are 3 other genetic
disorders caused by an abnormal
# of chromosomes?
Pg.49 - Abnormal
Human Karyotype
• Cut out the chromosomes
and arrange them into a
karyotype.
Homework
• Finish analysis questions
Out – pg.46
• All of the disorders we have seen result in
trisomy(3 chromosomes instead of 2 in a
homologous pair).
1. Do you think there are genetic
disorders where the individual has 4 or
more chromosomes instead of 2 in a
homologous pair?
2. How would this happen?
Wed 2/19
• Explain how mutations occur at the gene
level.
• Explain how mutations occur at the
chromosomal level.
• Recognize that the sequence of
nucleotides determines gene function.
In: pg.50
What causes mutations?
pg.51
Types of Mutation Chart-complete the chart
as we go through the types of mutations
MUTATIONS
Changes in DNA that affect genetic
information
What Causes Mutations?
• There are two ways in which DNA
can become mutated:
–Mutations can be inherited.
• Parent to child
–Mutations can be acquired.
• Environmental damage
• Mistakes when DNA is copied
Chromosome Mutations
Changes in number and structure of
entire chromosomes
Nondisjunction = Changes in number and
structure of entire chromosomes because a
chromosome fails to separate during meiosis
Chromosome Mutations
• Example: Down Syndrome
– Chromosome 21 does not
separate correctly.
– They have 47 chromosomes
in stead of 46.
– Children with Down Syndrome
develop slower, may have
heart and stomach illnesses
and vary greatly in their
degree of intelligence.
Sex Chromosome Nondisjunction
• Example:
Klinefelter’s
Syndrome
– XXY, XXYY, XXXY
– Male
– Sterility
– Small testicles
– Breast enlargement
Sex Chromosome Nondisjunction
• Example: XYY Syndrome
– Normal male traits
– Often tall and thin
– Associated with antisocial and behavioral problems
Sex Chromosome Nondisjunction
• Example: Turner’s
Syndrome
–X
– Female
– sex organs don't
mature at
adolescence
– sterility
– short stature
Sex Chromosome Nondisjunction
• Example: XXX
– Trisomy X, Triple X
– Female
– Little or no visible differences
– tall stature
– learning disabilities
– limited fertility
Chromosome Mutations
• Deletion: the loss of a piece of
chromosome due to breakage
Deletion Example
• Cri-du-chat
– Deletion of material on 5th
chromosome
– Characterized by the catlike cry made by cri-duchat babies
– Varied levels of metal
handicaps
Chromosome Mutations
• Inversion: a chromosomal
segment breaks off, flips around,
then reattaches
Chromosome Mutations
• Translocation: a piece of one
chromosome breaks off & reattaches to
a non-homologous chromosome
Gene Mutations
• Point Mutations =
– substitution, insertion,
or deletion of a single
nucleotide which is a
change that occurs
within the DNA of a
chromosome
Types of Point Mutations
1. Substitution = 1 nucleotide
replaces another
• THE FAT CAT ATE THE RAT
• THE FAT HAT ATE THE RAT
Types of Point Mutations
2. Insertion = 1 or more nucleotides are
added to a gene
• THE FAT CAT ATE THE RAT
• THE FAT CAT XLW ATE THE RAT
Types of Point Mutations
3. Deletion = 1 or more
nucleotides in a gene are lost
• THE FAT CAT ATE THE RAT
• THE FAT CAT THE RAT
Frameshift = shifts the reading frame of the
genetic message so that the protein may not
be able to perform its function.
• Caused by:
– Insertion
• THE FAT CAT ATE THE RAT
• THE FAT HCA TAT ETH ERA T
– Deletion
• THE FAT CAT ATE THE RAT
• TEF ATC ATA TET GER AT
Homework
. Finish
Karyotype and analysis
questions  pg.48-49
Out – pg.50
1. What type of mutations can you
diagnose with a karyotypechromosome or gene level?
2. Justify your answer to #1.
Thur 2/20
• INB Quiz today – get out half sheet, #1-10
• Explain how mutations occur at the gene
level.
• Explain how mutations occur at the
chromosomal level.
In: pg.52
1. What type of mutation do you
think happens most often?
2. Why?
Pg.53 - Types of Mutations
Concept Map
• With a partner, use the labels from the
envelope to create a concept map on the
white board.
• Use your notes pg.51 as reference.
• Copy the completed concept map into
your INB.
Homework
• Finish concept map
Out – pg.52
1. What type of mutation do you think
would be more harmful—gene level
or chromosome level?
2. Why?
Fri 2/21
• Explain how mutations occur at the gene
level.
• Explain how mutations occur at the
chromosomal level.
In: pg.54
1. T or F Mutations are changes in DNA.
2. T or F Mutations are harmful to the
organism that has them.
3. T or F All mutations are inherited.
4. T or F Different alleles for a trait arise
because of mutations.
5. T or F Mutations cause a change in the
organism because they change the protein
that is coded for by the DNA.
Significance of Mutations
• Most are neutral
• Eye color
• Birth marks
• Some are harmful
• Sickle Cell Anemia
• Down Syndrome
• Some are beneficial
• Atherosclerosis is principally a disease of the
modern age, one produced by modern diets and
modern life-styles. There is a community in Italy
near Milan whose residents don't get
atherosclerosis because of a fortunate mutation in
one of their forebearers. This mutation is
particularly interesting because the person who had
the original mutation has been identified.
Pg.55 - Read the articles and answer the
The Incredible Bulk
1.
2.
3.
4.
5.
following questions.
What mutation does Wendy have?
What is her phenotype like because of this mutation?
Why do whippets that are heterozygotes for the mutation
have an advantage?
Is this mutation neutral, helpful or harmful to whippets?
Why are scientists interested in this mutation?
All Blue-Eyed People are Related
1.
2.
3.
4.
5.
What did Danish researchers conclude about blue-eyed
people?
What is the difference in the DNA between a brown-eyed
and blue-eyed person?
Is this an example of a gene level or chromosomal level
mutation?
How does the mutation cause blue eyes?
Is this mutation neutral, helpful or harmful?
Homework
Out – pg.54
• A friend says “All mutations are
harmful”. What would you say to
them in response to this statement?
• Be NICE! Give examples!
3+ sentences
Mon 2/24
• Updated grades are posted on window!
• Chp.12 Test and INB Check FRIDAY!!!
• Explain how mutations occur at the gene
level.
• Explain how mutations occur at the
chromosomal level.
In: Pg.56
1. What is one example of a genetic
disease?
2. What makes a disease “genetic”?
Pg.57 - Genetic Diseases movie
clip (7 minutes)
• Write down 3 facts as you watch
Pg.58 - Use table 12-1 in the textbook
(pg.246).
Analysis Questions:
1. What does it mean when a disease
is “autosomal dominant”?
2. What are the symptoms of
Phenylketonuria?
3. What affect does the mutation of
coagulation factor 8 have on a
person with hemophilia?
4. Tay-sachs disease causes death in
early infancy. How does this gene
continue to exist if the people with
the disease die before they have
children?
5. Why do you think the breast cancer
gene(BRCA1) is only found in 8% of
breast cancer patients?
6. Why are there more autosomal
diseases than sex-linked diseases?
Pg.59
Genes and
Diseases Map
1. Glue in the
table
2. Use the
chromosome
chart to find
the disorders,
then fill in the
table
Homework
Finish analysis questions
Out – pg.56
1. If you had the gene for a genetic disease
like cystic fibrosis, who do you think
should have access to that information—
your doctor, insurance company,
employer, spouse, etc?
2. Why?
Tues 2/25
• Chp.12 Test and INB Check FRIDAY!!!
• Predict patterns of inheritance by
employing Punnett squares, probability or
pedigree analysis.
In: pg.60
What are 5 rules for creating pedigrees?
Pedigree = a graphic representation of genetic
inheritance
1. Shape:
• circle = female ○
• square = male □
2. Shading:
• shaded = show the trait ● ■
• unshaded circles/squares = do not show the trait
• half-shaded circle/square = carrier (heterozygous)
3. horizontal line = parents ○▬□
4. vertical line = offspring
5. Each row is a generation, with the most recent
generation on bottom.
Pg.61 - Pedigree Activity
• With a partner, create the pedigree
describe in the “Pedigree Activity” on
the white board.
• Make sure you include a key!!!
• Copy your final pedigree into your INB.
• Glue in your copy of the info sheet
Homework
• Reminder: Test & Notebook
Check are on FRIDAY!!!
Out – pg.60
1. What do all
hemophilia
sufferers
have in
common?
2. What do all
hemophilia
carriers
have in
common?
Wed 2/26
• Chp.12 Test and INB Check FRIDAY!!!
• Predict patterns of inheritance by
employing Punnett squares, probability or
pedigree analysis.
In: pg.62
• How can you tell if a disease is autosomal
or sex-linked based on a Pedigree?
(hint…look at the 2 examples below)
Pg.63
• Glue in and complete Pedigree Charts
Practice sheet
After…get ready for notebook
check on Friday!
Chp.12 (pgs.35-63)
Table of Contents
Vocab pg.38-39 (with pics)
Gene Spy pg.44
Who gets the $ pg.45
Karyotype complete pg.49
Karyotype Questions pg.48
Incredible Bulk/Blue Eyes Questions pg.55
Genes & Diseases Analysis Questions pg.58
Pedigree Practice Sheet pg.63
OUT – pg.62
• Which type of inheritance will often
skip generations?
Thur 2/27
• INB Quiz #4 Today  get out half
sheet #1-8
• INB check TOMORROW
• Chp.12 Test TOMORROW!!!
After…get ready for notebook
check tomorrow!
Chp.12 (pgs.35-63)
Table of Contents
Vocab pg.38-39 (with pics)
Gene Spy pg.44
Who gets the $ pg.45
Karyotype complete pg.49
Karyotype Questions pg.48
Incredible Bulk/Blue Eyes Questions pg.55
Genes & Diseases Analysis Questions pg.58
Pedigree Practice Sheet pg.63
Chp.12 Study Guide
• Complete on separate sheet of paper
• Take home and study it!
• Due Monday as separate grade!
Friday 2/28
• Collect Study Guides  Any Questions???
• INB Check #3
• Chp.14, 15, 16 Title Page
Pg.65 (skip pg.64)
• Chp.14, 15, 16 Title Page
–Write title of all 3 chapters
–3 pictures (one from each chapter)
–3 key words (one from each chapter)
–3 colors