Transcript - The Multiliteracies Project

Genetics
Review
I have a
Theory
What is…
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Mendel,
Mendel,
Mendel, it’s
always about
Mendel
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Re-pro-duce!
Re-pro-duce!
DNA
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What is the difference between
genotype and phenotype?
Genotype is the set of genes which is
responsible for a particular trait. It is the
genetic make-up of an organism.
Phenotype is the appearance or physical
expression of that trait
Skin color is coded for by several
different genes which results in a
range of skin colors from very dark to
very light. This is an example of
Polygenic inheritance
___________________
Who developed the two fundamental
principles of heredity and what are they?
•Gregor Mendel
•Mendel’s First Law = Law of Segregation or
Law of Inheritance, which states that
inherited traits are determined by genes,
which segregate (separate) in the gametes
•Mendel’s Second Law = Law of Independent
Assortment, states that the inheritance of
alleles for one trait does not affect the
inheritance of alleles for another trait
If you have a tall individual, where tall
is dominant over short. How do you tell
if they are homozygous or
heterozygous?
Test cross with recessive
individual.
Using
Blending
Red andtheory
Whitewas
flowers
the idea
in your
explanation,
that the traits
describe
of anthe
offspring
theory of
blending
would
inheritance
be a blend
andof
why
its it was
parents’
traits.
So a red
considered
incorrect.
flowered plant and a white
flowered plant would produce
offspring with pink plants. This
was considered incorrect
because rarely did this ever
actually happen in nature.
What is heterozygous advantage?
Situation in which heterozygous
individuals have an advantage over
both homozygous dominant and
homozygous recessive individuals.
What are genes that do not
assert independently due to
their proximity to each other on
the same chromosome called?
Linked genes.
What is a karyotype and what is
it’s purpose?
It is the evaluation of the size,
shape and number of
chromosomes to help identify
genetic problems as the cause of a
particular disorder or disease.
What is a carrier?
An individual that has inherited the
recessive allele for a certain genetic
trait, but does not express that trait; it
carries that trait and can transmit it to
its offspring.
What is a Punnett Square?
It is a table used to calculate the
probability of genotype and phenotype of
offspring or it is a simple method of
illustrating all possible combinations of
gametes from a given set of parents
What is the difference between
Mendel’s 3:1 ratio and Mendel’s 1:2:1
ratio?
Mendel’s 3:1 ratio is based on
phenotype while Mendel’s 1:2:1
ratio is based on genotype
What is the difference between
cross-pollination and self-pollination?
Cross-pollination is the transfer of
pollen from one plant to another plant
of the same species. Self-pollination is
the transfer of pollen to the pistil of the
same flower
Why was cross-pollination
important during Mendel’s pea
plant breeding experiments?
Because it allowed Mendel to control
the breeding patterns in his pea plants
easily.
What is the difference between ‘F1
generation’ and ‘F2 generation’ between
two true breeding plants with opposite
forms of a trait?
F1 generation are all (100%) heterozygous
and are the parents of F2 generation. F2
generation are 25% homozygous
dominant, 50% heterozygous, 25%
homozygous recessive
Plant A has Red flowers and was self
Plant
B is
heterozygous
and
a
fertilized
and
produced
100 red
flowered
theRed
white
flower
plants.carrier
Plant Bofhas
flowers
and was
allele.
The reason
the numbers
self
fertilized
and produced
79 red
of theplants
plantsand
don’t
followflowered
the
flowered
21 white
ratio
perfectly
is because
the
plants.
Why
did Plant
B produce
white
ratioifisitonly
a probability
of the
flowers
was red
and why do
phenotypes.
numbersthe
of possible
plants produced
not perfectly
follow the mendelian ratio?
What is the difference between
Mitosis and Meiosis?
Mitosis is the cell division process that
occurs in somatic cells where cells
divide only once, its purpose is for
tissue repair, growth and cell
replacement. Meiosis is the cell
division process that occurs in gametes
or germ cells where cells divide twice.
Females carry 2 x chromosomes and
males only have one. Why do we not
see a different in the expression of xlinked genes between males and
females?
Due to Barr bodies, one of the x
chromosomes condenses and
becomes deactivated.
Four viable sperm cells are
______
produced at the end of mitosis, and
One viable eggs are produced at
_______
the end of mitosis.
The diploid number of chromosomes
for dogs is 78. How many
chromosomes are in the gamete cell of
a dog?
39
What disease do these characteristics
represent? What is it caused by?
• Single x-chromosome
• Sterile female
• Partially developed secondary sexual features
• 1 in 5,000 live births.
Turner Syndrome (XO), Aneuplodity
What is the method of
replication that uses one parent
and one daughter strand to
make new strand of DNA?
Semiconservative
What is cloning?
It is the production of identical
copies of molecules, genes,
cells, or even entire organisms.
What can cause mutations?
Toxic compounds, radiation
and viruses.
Which of the chromosomes shown here
are homologous?
All but 4
DNA is a long strand molecule
consisting of repeating nucleotide
units. Chromosomes are a length of
Explain
theeach
relationship
between
DNA. On
chromosome
are
alleles,
DNA.
specificgenes,
geneschromosomes
which code forand
different
traits. Alleles are different forms (or
versions) of a gene. Each chromosome
has the same gene, but may have
different alleles of that gene
Game 2
Typical, just
typical
Dominance
Technologies
What’s
normal?
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Be Positive
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Widow’s peak is a simple dominant trait
(W). If a student does not have a widow’s
peak, and we know that her father
doesn’t either but her mother does, what
are the genotypes of all 3 individuals?
The father would be homozygous
recessive (ww), the student would be
homozygous recessive (ww), but the
mother would have to be heterozygous
(Ww)
In humans, albinism (lack of skin
pigment) is due to a recessive gene.
Suppose that two normally pigmented
parents produce an albino child. What
are the chances of their second child
also being albino?
25%
A male and female guinea pig are
both heterozygous for fur colour and
fur texture. Both dark fur (A) and
rough fur (B) are dominant traits.
Determine the frequency of offspring
that have rough and dark fur.
9/16
If the offspring of two tall plants are
crossed and the exact genotype of
each parent is unknown, using the
principle of dominance what are the
odds of having AA offspring?
7/12
In cattle, horns (h) are recessive over
hornlessness
(H). A hornless
Bull: hornless
(Hh) bull is
crossed Cow
with A:
three
cows,(hh)
A, B, and C.
horned
Cow A isCalf
horned
and produces
A1: horned
(hh) calf A1
which is Cow
also horned.
Cow
B
is
hornless
B: hornless (Hh)
and produces calf B1, which is horned.
Calf B1: horned (hh)
Cow C is horned and produces calf C1,
Cow C: horned (hh)
which is hornless. Give the genotypes
Calf
C1:
hornless
(Hh)
and phenotypes of all seven animals
A calico cat has 2 different
coloured patches on its body
what causes this phenomenon
Codominance
What is the difference between
incomplete dominance and
codominance?
Incomplete dominance means neither
allele types are dominant.
Codominance means both allele types
are dominant
What is the difference between
codominance and multiple
alleles inheritance?
Codominance is when there is a
possibility of two alleles being
expressed equally, whereas multiple
alleles inheritance is when there is
more than possible two allelic forms of
a gene.
If a homozygous black bull is
mated with a homozygous
white cow and the calf is gray,
this would be an example of
Incomplete Dominance
____________________.
However, if the calf has black
and white spots this would be
an example of
Codominance
_______________.
A farmer wants to establish a
pure strain of roan cattle that
breeds true. Why is this
impossible?
Roan is codominant, RWRR, so when you
cross them you don’t get a 1:0, you get a
1 white : 2 roan : 1 red
The giant panda is an endangered species
partially due to the very small window
that females are receptive to breeding.
Natural inseminations by males rarely
result in a fertilized egg. What method
might a laboratory conservationist be
able to use to ensure egg fertilization?
in vitro fertilization
What is one benefit of
developing genetically
engineered medical products
such as insulin?
Cheaper to make in large quantities.
Why are stem cells so important to
medical research?
They are unspecialized cells that have
the potential to be made into organs
and other tissues that the body will not
reject.
Explain one way cloning is used today.
Cloning is used in agriculture to produce many copies
of the same high-quality crop plant. In medicine,
cloning is used to produce identical strains of bacteria
for research. Gene cloning is used to make certain
medications such as insulin. Cloning (through
Polymerase Chain Reaction) is used to copy DNA
sequences for crime scene investigation
Prenatal genetic testing has significant
benefits. However, many ethical
dilemmas are also associated. Name one
dilemma.
Termination of pregnancy or potential
discrimination against persons with
disabilities.
A phenotypically normal male who has a
hemophilic brother marries a
homozygous normal woman. What is
the probability that any of their children
will be hemophilic?
0%, not possible
What disorder is a mucus causing
inflections in lungs and pancreas, and
causes males to be infertile?
Cystic Fibrosis
What disorder is this showing?
What is the cause?
Trisomy 21 (Downs syndrome),
non-disjuntion
Looking at the following pedigree, what
type of disorder can you rule out?
Can not be X-linked
Sickle cell disease is caused by a single
mutation in the DNA of a particular
gene. A person with this disease has red
blood cells that lose their original donut
shape and form a sickle shape. People
with this disorder suffer from low energy
levels, blood clots, and strokes. This is an
example of
Pleiotropy
_______________.
Progeria is a rare autosomal dominant
disorder that causes individuals to age
rapidly. If one parent is normal and the
other had a mutation leading to the
abnormal gene causing the disease,
what is the probability that their
offspring will inherit the disease?
50%
A woman with blood type B has a child
with blood type O. She claims the child
is a man’s with blood type A. Is it
possible that this child is his?
Yes
Codominance
because
A andofB
Are human blood
typesalleles
examples
can
be expressed
equallyorincodominance
an individual
incomplete
dominance
as AB. Bothand
thewhy?
A and the B are
expressed (thus are both dominant). If
human blood types were an example of
incomplete dominance, alleles A and B
would form an intermediate phenotype
of A and B. In other words, neither A
nor B would be expressed in the
individual
Identical twins both have blood type O,
and the mother also has blood type O.
What are the possible blood types of
the father?
AO, BO or O
Mrs. Doe and Mrs. Roe had babies at the
same time. Mrs. Doe took home a girl and
named her Nancy. Mrs. Roe received a boy
and named him Richard. However, Mrs. Roe
was sure she had a girl, and sued the
hospital. Blood tests showed that Mr. Roe
was type O and Mrs. Roe was type AB. Mr.
and Mrs. Doe were both type B. Nancy was
type A and Richard was type O. Had an
exchange occurred?
Yes