Transcript Genetics Since Mendle

Daily Science
1. Cabbage Patch Mama has dimples.
Cabbage Patch Papa does not have
dimples. All three children have
dimples. Dimples are dominant over
non-dimples. Give the probable
genotypes of Mama and Papa.
2. Vocabulary Review, Explain the
following: Phenotype, Genotype,
Genetics, Heredity, Zygote,
Heterozygous, Homozygous, Dominant,
Recessive
Standard
S7L3
UNDERSTAND THE IMPORTANCE OF AND
HOW BIOLOIGICAL TRAITS ARE PASSED ON
FROM GENERATION TO GENERATION
Learning Target
I can understand how heredity does
not always follow Mendelian rules.
Genetics Since Mendel
Gregor Mendel--A Reminder
• Austrian Monk who is considered the
“Father of Genetics.”
• Mendel’s Rules:
– Traits are controlled by 2 or more
alleles.
– One allele may be dominant. The
other may be recessive
– Alleles separate in gametes during
meiosis.
If Gregor Mendel were given a black
mouse & a white mouse
• What would he have said about the
offspring?
• He would have said that the
phenotype of the offspring
resembled one of the parents.
• Would he have considered a GRAY
mouse as an offspring?
• A gray mouse is possible, but how?
Genetics Today
Not Always Following the “Rules”
Incomplete Dominance
• This is a heterozygous condition in
which both alleles are PARTIALLY
expressed. (One allele for a specific trait
is not completely dominant over the
other allele)
• The offspring will be a blended form.
This form will be different than the
HOMOZYGOUS forms of either
parent.
Incomplete dominance
This is a form of
intermediate
inheritance in
which one allele for
a specific trait is not
completely
dominant over the
other.
Offspring of Incomplete Dominance
1. In incomplete dominance three
phenotypes are involved:
One for EACH parent and a third
separate (distinct) phenotype for
the offspring.
2. The trait in the offspring is a
BLEND (or mixing) of the parental
traits.
Incomplete Dominance continued:
3. Neither allele for a
trait is dominant.
4. The heterozygous
phenotype is
intermediate or is
between the
homozygous parent
forms.
5. For Example:
In a Chestnut Horse the dominant color is
chestnut (red).
In a Cremello Horse the dominant color is
creme/white.
Because both colors are equally dominant, the
offspring is a color called Palamino.
Chestnut Horse + Cremello Horse = Palomino
Say it Again?
• A palomino horse will result when a chestnut
horse and Cremello colored horse are crossed.
• This is because the heterozygous palomino gets
a single allele of a cream colored gene crossed
with a red (chestnut) gene.
6. Incomplete Dominance
7. Try the following cross:
Red Four O'clocks X White Four O’clocks
____ ____ X ____ ____
Use 2 different capital letters
All of the offspring were pink.
This is intermediate between red and
white.
Codominance
1.
2.
3.
Neither phenotype is dominant.
Instead, the individual expresses
both phenotypes.
Co – both are dominant enough to
be expressed!!
A hybrid offspring will
show a third phenotype.
Dominique Chickens
Co-Dominance
• “CO” means together - Cooperate; CoCaptain
• with INCOMPLETE DOMINANCE, there is
a blending of traits.
• With CO-DOMINANCE, BOTH traits
appear TOGETHER in the offspring.
For Example
• With INCOMPLETE DOMINANCE, a red and
white flower will produce a pink flower.
• In CO-DOMINANCE, a red and white flower
will produce a red and white spotted flower.
Multiple Alleles
1. Within the population, there may
be multiple forms for alleles.
2. Many traits are controlled by more
than TWO alleles. These are said to
be controlled by multiple alleles.
3. Blood type is an example of
multiple alleles.
Blood Type/Multiple Alleles
4. The alleles for blood type are A, B, and O.
5. Both A and B are dominant. They are said
to be co-dominant.
6. O is recessive.
Blood Type/Multiple Alleles
7. If someone had the A and B alleles, the
blood type would be AB.
(Both are
exhibited/co-dominant)
8. If someone exhibits blood type A, do
both alleles have to be A? NO Explain:
since A is dominant over O; someone
could be AA or AO
9. For someone to have the blood type O,
both parents would have to carry the
allele for O blood type.
Answer the following.
10. A man with blood type B marries a woman
with blood type A. Their first child is blood
type O. Predict what other blood types are
possible for any children they may have in the
future.
_____ _____ X _____ _____
Polygenic Inheritance
1. Poly is a prefix meaning more than one.
2. Polygenic inheritance occurs when a
group of gene pairs act together to
produce a trait.
3. Eye color, height, hair color, and skin
color are examples of polygenic
inheritance.
Environmental Role
1. The environment plays a role in how
some of your genes are expressed.
2. These influences may be internal or
external.
3. Example: Some people may be at risk
for skin cancer. These people need to
limit their exposure to the Sun.
Recessive Genetic Disorders
1. Both parents have a recessive allele
that is responsible for the disorder and
pass it on to the child.
2. Because the parents are heterozygous,
they don’t show symptoms.
3. Treat this as dominant/recessive when
working Punnett square problems.
Work these out on a sheet of
notebook paper or on notes.
Determine if these disorders are passed to the
offspring:
1. A mother has retinoblasoma and the father is
not a carrier. This is a cancer found in the eye.
2. A father is a carrier for Tay-Sachs and the
mother is not a carrier. This is a deterioration
of the nerve cells.
Will the offspring be male or female?
1. Chromosomes/genes that determine the sex
of an organism are XX in females and XY in
males.
2. Females produce eggs with an X chromosome
only.
3. Males produce sperm with either an X or a Y
chromosome.
4. Who determines the sex of the offspring?
Sex-Linked Disorders
1. An allele inherited on an X or Y
chromosome is a sex-linked gene.
2. Color blindness is a sex-linked disorder
caused by a recessive allele on the X
chromosome.
3. Complete the Punnett square for color
blindness. Who would inherit the trait?
The superscript C denotes the allele for color blindness.
XY X XcX
What if?
• Would a father who exhibited this trait
(colorblindness) pass it on to his son or
daughter?
• Why?
• Would this offspring have the
disorder?
What if?
• Would a father who exhibited this trait
(colorblindness) pass it on to his son or
daughter? Daughter
• Why? This trait is a sex linked gene on the
X chromosome.
• Would this offspring have the disorder? For
this cross, the female would be a carrier.
Hemophilia in humans is due to an Xchromosome mutation. What will be the
results of a cross between a normal (noncarrier) female and a hemophiliac male?
All sons are normal and all daughters are
carriers.
Mutations
1. Mutations occur when a gene is altered or
copied incorrectly.
2. A mutation may be harmful, beneficial, or
have no effect.
3. Chromosome disorders are caused by
more or fewer chromosomes than
normal.
4. These can occur because of mistakes
during the process of meiosis. (Which
would pass this disorder to the offspring.)
Pedigree
• A pedigree follows a trait through
generations of a family.
• https://www.youtube.com/watch?v=Wuk0
W10EveU
Selective Breeding
1. Involves selecting qualities within individuals
of a breed that are desired so that these
qualities may be passed on to the next
generation.
2. Inbreeding produces individuals with similar
characteristics.
Selective Breeding
3. Hybridization involves crossing
individuals with different traits.
– This is done with the hope of producing
offspring with the best traits of both
organisms.
What is genetic engineering?
1. Today scientists can use biology or chemistry
to change the arrangement of DNA that makes
up a gene.
2. This is used today for many reasons. One of
those reasons is to produce larger volumes of
medicine.
3. Cloning is a type of genetic engineering.
4. In cloning, the genetic information from a
single cell of an organism is used to produce
another organism with the same genetic
information.
What is genetic engineering?
• Today scientists can use biology or chemistry to
change the arrangement of DNA that makes up a
gene.
• This is used today for many reasons.
One of
those reasons is to produce larger volumes of
medicine.
• Cloning is a type of genetic engineering.
• In cloning, the genetic information from a single cell
of an organism is used to produce another organism
with the same genetic information.
What other ways can genes be used?
1. Genes can be changed by scientist to make
plants more resistant to disease.
2. Genes from one type of plant may be inserted
into another type of plant to help fight crop
diseases!
Standard
S7CS7
Students will question scientific claims and
arguments effectively.
Socratic Seminar on Genetic
Engineering
1. Must be prepared!!!!
2. Must have note cards with facts. (Have at
least 20)
3. Must anticipate every question to have a
rebuttal.
4. Work with others
5. This will be conducted as a discussion in the
round.
Bias
• What are the sources? Are they reliable?
• All advertising is biased. Think of some
examples.
• Look for generalities. (Ex: “A number of
scientists”, not naming specific studies, etc.)
• Your group will create a print advertisement
of pro/con of GM food.
Daily Science
1. Excessive hair on the ears is a Y-linked disorder.
If a male has this disorder, who will inherit it?
2. Shirley suffers from an X-linked recessive
disorder. Her husband, Frederick, is normal.
How will this affect her sons? Her daughters?
3. A woman with type B blood marries a man with
type A blood. Is it possible for them to have a
child with type O blood? Explain.
Thursday 1/15/15
1. Is the following karyotype from a human?
How can you tell? Is this from a male or
female?
2. Can a child inherit a recessive disorder if one
parent does not have the disorder, nor is a
carrier for the disorder?Explain
Answer the Following
1. What are GMOs? What are transgenic
organisms? (This is not explained, but you
should be able to infer from the reading.)
2. How are GMOs different from organisms
obtained through selective breeding?
3. In the concluding paragraph, what are
positives and what are negatives about
GMOs?
Broken down, this
means …