Transcript Genetics - myteacherpages.com

Introduction to Genetics: Answer the following T/F
questions in your notebook. Then write 3 questions you
hope to have answered by the end of the unit.
1)
2)
3)
4)
5)
Girls inherit more traits from their mother than their father
You have inherited traits that are not apparent/visible
Color blindness is more common in males than females
Identical twins are ALWAYS the same sex
A person can transmit genetic traits to their offspring which they
themselves DO NOT show
6) The father determines the sex of a child
7) The total number of male births exceeds female births each year
8) Acquired characteristics, like mathematical skills, can be inherited
9) Fraternal twins are more closely related to each other than to
other siblings
10) Some traits that are inherited are a blend of the mother and
fathers
• Genetics is the field of biology
devoted to the study of genes,
heredity, and genetic variation in
living organisms.
• Heredity is the passing of traits from
parents to their offspring.
Inheritance
• Why do you look like your parents? Or even
your grandparents?
• You inherited the genes for traits from your
parents (only half or one copy from each)
when their gametes combined to make you!
• Those genes (segments of DNA bases) code
for making proteins (protein synthesis & gene
expression) which are responsible for
producing your traits.
Characteristics vs. Traits
• In today’s activity you’re going to compare
characteristics and traits and whether they are
inherited or acquired traits.
• A characteristic is a genetically heritable
feature like eye color.
• A trait is the variation of a particular
characteristic. For example blue, brown, or
green would be traits if the characteristic is
eye color.
Inherited vs Acquired Traits
• A trait is inherited if it can be determined by the
genes on your chromosomes that you received
from your mother and father.
• A trait is acquired if it was NOT passed on
genetically and is instead gained through
experience.
– Dying your hair; you pass on your original hair color
trait to your child
– Working out to build muscle strength; your child will
not be naturally muscular just because you were
– Effects of plastic surgery cannot be passed on
Date: 1/21/15
Objective: Understand the experiments conducted by
Gregor Mendel and the laws he developed because of
them.
QOD: Using this bird as an example, state one
inherited and one acquired trait.
Agenda:
1.QOD
2.Notes
3.Reading guide
Homework: Traits vs Characteristics activity due
tomorrow
MENDELIAN GENETICS
Early ideas about heredity
• Until the 19th century, scientists
thought that traits were inherited
by blending.
• For example, a tall plant and a short
plant would create a medium plant.
• The experiments conducted by
Gregor Mendel helped to disprove
this idea.
Gregor Mendel
The “Father of Genetics”
• Austrian monk, teacher, scientist,
gardener
• Questioned the blending theory
of inheritance because it didn’t
support what he observed in the
garden of the monastery
• Experimented with pea plants to
investigate how traits were
passed from parents to offspring
• Credited with formulating the
basic laws of heredity that still
govern the study of genetics
today
Mendel’s 7 Traits
• Traits – genetically determined variations of a
characteristic
– Example: Tall vs. short (plant height) or Green vs.
yellow (pod color)
First Experiments – Flower Color
• P Generation are
purebred (only contain
one version of trait)
• F1 – 100% Hybrids
(contain a trait for white
and a trait for purple)
• F2 – 3:1 ratio of purple
to white flowers, white
trait reappears
Conclusions
• Mendel concluded that two factors
control a given characteristic, one of
which dominates the other, and these
factors separate and go to different
gametes when a parent reproduces.
• He called this the Law of Segregation.
Law of Segregation
Each parent only gives one allele of
the two they posses to their
offspring
Important Vocabulary
• Today we refer to Mendel’s
“factors” as alleles and we
represent them by using
upper and lower case
letters.
• Allele – alternative form
of a gene abbreviated
using letters
– Tall (T) or short (t)
– Green (G) or yellow (g)
• Mendel found that one factor or
allele is usually dominant and one
is recessive.
• Dominant – the allele
that is expressed and
masks the recessive form;
shown with capital letter
• Recessive – the allele that
is only expressed when
two recessive alleles for
the same characteristic
are inherited; shown with
lower case letter
Note: Complete dominance means one trait is completely dominant over the other
Alleles (different versions of a gene) are
found on homologous chromosomes
Second Experiments
• Mendel wondered whether different
characteristics are inherited together.
• For example, are yellow seeds and round
seeds always inherited together? Or do these
two characteristics show up in different
combinations in offspring?
• He investigated the inheritance of two
characteristics at a time…
Second
Experiments
• P Generation – purebred
• F1 – 100% Hybrid, each
contain one version of
each trait
• F2 – 9:3:3:1 ratio with 4
different variations
• These two traits are
therefore NOT inherited
together
Conclusions
• Mendel, like any good scientist, repeated
experiments using different combinations of
characteristics and got the same results.
• He concluded that factors controlling different
characteristics are inherited independently of
each other.
• He called this the Law of Independent
Assortment.
Law of Independent Assortment
Brown eyes
Black hair
Blue eyes
Red hair
Brown eyes
Red hair
Blue eyes
Black hair
Linked Genes
• Although many traits do not influence the
inheritance of other traits, some DO.
• This is because they are usually located on the
same chromosomes.
• These are called linked genes.
• Example: red hair and freckles
Gene Expression
• Recall that genes are segments of DNA that
code for traits. Traits are expressed via
proteins.
• Gene expression is the activation or “turning
on” of a gene that results in transcription and
the production of a protein.
• Mechanisms to control gene expression have
evolved so that each protein is made by a
particular cell only when needed.
END
Date: 1/23/15
Objective: How are Punnett squares used to show
probability.
QOD: What is the probability of getting tails/tails if
you “cross” a trick coin hh and a regular coin Hh. (Try
to do a Punnett square)
DUE: Probability Lab
Agenda:
1.QOD
2.Notes
3.Foldable
4.Reading guide or HW
Homework: Complete questions 1-14.
Friday Review
•
•
•
•
•
Who is the “Father of Genetics”?
How would you describe the P-generation?
What happened in the F1 generation?
What does it mean if a trait is dominant?
How many alleles or factors do organisms get
from their parents?
• What does the Law of Independent
Assortment explain?
Activity
Probability Lab
Important Vocabulary
• Dominant allele – masks the recessive form, a
capital letter ex. Tall (T)
• Recessive allele – only expressed if dominant is
not present, a lower case letter ex. Short (t)
• Homozygous – having two of the same alleles for
a trait ex. Homozygous dominant – tall TT
ex. Homozygous recessive – short tt
• Heterozygous (hybrid) – have one of each allele
or version of a trait ex. Heterozygous - Tall Tt
Important Vocabulary
• Genotype – an organism’s genetic material; as
in what are their alleles or letters
– Homozygous dominant TT
– Heterozygous Tt
– (homozygous) recessive tt
• Phenotype – an organism’s physical
appearance like tall or short
Punnett Squares
A tool used to show the possible
genetic combinations of a genetic
cross between two parents
Show a cross between a purebred purple
flower and a purebred white flower
Parent plant
genotypes
Parent plants
possible
gametes
PP
P
X
P
pp
p
This supports the Law of Segregation
p
Show a cross between a purebred purple
flower and a purebred white flower
Parent plants
possible
gametes
1. Separate each
parents’ alleles
by writing each
set on one side
of the Punnett
square
P
P X p
p
Show a cross between a purebred purple
flower and a purebred white flower
1. Separate each
parents’ alleles by
writing each set on
one side of the
Punnett square
p
P
P
p
Show a cross between a purebred purple
flower and a purebred white flower
2. Fill in the squares
to show the possible
allele combinations in
the offspring by
bringing the letters
over and down into
each box.
Capital letters go first.
p
p
P
Pp
Pp
P
Pp
Pp
Show a cross between a purebred purple
flower and a purebred white flower
3. Calculate the genotypic
and phenotypic ratios
Genotypic ratio is PP:Pp:pp
Phenotypic ratio is
dominant:recessive
So,
Genotypic ratio = 0:4:0
Phenotypic ratio = 4:0
100% are purple
p
p
P
Pp
Pp
P
Pp
Pp
Each square represents a
possible zygote allele
combination (offspring)
Show a cross between two heterozygous
purple flowered plants
Parent plants
possible
gametes
1. Separate each
parents’ alleles
by writing each
set on one side
of the Punnett
square
P
p X P
p
Show a cross between two heterozygous
purple flowered plants
1. Separate each
parents’ alleles by
writing each set on
one side of the
Punnett square
P
P
p
p
Show a cross between two heterozygous
purple flowered plants
2. Fill in the squares
to show the possible
allele combinations
in the offspring by
bringing the letters
over and down into
each box. Capital
letters go first.
P
p
P
PP
Pp
p
Pp
pp
Show a cross between two heterozygous
purple flowered plants
3. Calculate the genotypic
and phenotypic ratios
Genotypic ratio is PP:Pp:pp
Phenotypic ratio is
dominant:recessive
So,
Genotypic ratio = 1:2:1
Phenotypic ratio = 3:1
75% purple 25% white
P
p
P
PP
Pp
p
Pp
pp
Each square represents a
possible zygote allele
combination (offspring)
• Explain Mendel's laws in genetic terms, that is,
in terms of chromosomes, genes, and alleles.
• Explain the relationship between genotype
and phenotype. How can one phenotype
result from more than one genotype?
Monohybrid means looking at one trait at a time
PRACTICE MONOHYBRID CROSSES
Let’s do a Punnett square for BB x Bb
B= black fur in bunnies
b= white fur in bunnies
So black fur is dominant
B
1. Separate each
parents’ alleles by
writing each set on
one side of the
Punnett square
B
B
b
Let’s do a Punnett square for BB x Bb
B= black fur in bunnies
b= white fur in bunnies
So black fur is dominant
2. Fill in the squares
to show the
possible allele
combinations in the
offspring by
bringing the letters
over or down into
each box. Capital
letters go first.
B
b
BB
Bb
B
B BB Bb
Let’s do a Punnett square for BB x Bb
B= black fur in bunnies
b= white fur in bunnies
So black fur is dominant
3. Calculate the genotypic
and phenotypic ratios
So,
Genotypic ratio = 2:2:0
Phenotypic ratio = 4:0
What are the chances of a
white bunny?
B
B b
BB Bb
BB
Bb
B
Let’s do a Punnett square for a
heterozygous bunny and a white bunny
B= black fur in bunnies
b= white fur in bunnies
B
1. Separate each
parents’ alleles by
writing each set on
one side of the
Punnett square
b
b
b
Let’s do a Punnett square for a
heterozygous bunny and a white bunny
B= black fur in bunnies
b= white fur in bunnies
2. Fill in the squares
to show the
possible allele
combinations in the
offspring by bring
the letters over or
down into each box.
Capital letters go
first.
B
b
Bb
bb
b
b Bb bb
Let’s do a Punnett square for a
heterozygous bunny and a white bunny
B= black fur in bunnies
b= white fur in bunnies
3. Calculate the
genotypic and
phenotypic ratios
So,
Genotypic ratio = 0:2:2
Phenotypic ratio = 2:2
What are the chances of
a white bunny?
B
b
Bb
bb
b
b Bb bb
TEST CROSS
What is a test cross?
• When the genotype of an organism is
unknown, it can be determined if you cross it
with an individual that is homozygous
recessive.
• Test crosses are often used in breeding (like
dog breeding) to determine if organisms are
really “pure bred” (homozygous) for desired
characteristics.
Problem
• You’re a rabbit breeder and you want to breed
black bunnies and you do not want any white
bunnies.
• What should the parent bunnies genotypes be
to ensure they always produce black bunnies?
– Black = B (dominant)
– White = b (recessive)
BB x BB
• What color bunny should you cross your black
bunnies with to figure out their genotype?
• You’re looking for the bunny that when mated
with the white bunny, never produces any
white bunnies.
• Lets observe the Punnett squares that
illustrate this situation
Test Crosses
If your black bunny is
homozygous dominant:
b
If your black bunny is
heterozygous:
b
b
b
B
Bb Bb
B
Bb Bb
B
Bb Bb
b
bb bb
100% of the time black bunnies are
produced. YAY! This means your
bunny is purebred – BB!
50% of the time black bunnies are
produced. BOO!
If your bunny makes white bunnies,
you know they are not purebred, its
heterozygous Bb.
Looking at two traits together, instead of just one
DIHYBRID CROSSES
52
Predicting Dihybrid Crosses
• Dihybrid crosses track the inheritance of
two traits together.
• Let’s do a cross between two
heterozygous tall, heterozygous purple
flowered pea plants
–So, TtFf x TtFf
–This also mean instead of a 2x2 box,
we’ll have a 4x4 box
Predicting Dihybrid Crosses
• Before when looking at one trait, we separated each into their
own gamete, so one letter was above each box on the
Punnett square.
• Now, there will be two letters above each box to show that
there are two traits inherited together in each gamete.
• We FOIL to determine the 4 possible gamete combinations.
TtFf
Predicting Dihybrid Crosses
• Phenotypic Ratios
– Tall, purple : tall,
white : short, purple
: short, white
• Keep same letters
together, capitals 1st
• You will not be asked
for genotypic ratios for
dihybrid crosses
Predicting Dihybrid Crosses
• Phenotypic Ratio
– 9:3:3:1
TTFF TTFf TtFF
TtFf
TTFf
TTff
TtFf
Ttff
TtFF
TtFf
ttFF
ttFf
TtFf
Ttff
ttFf
ttff
Example of useful dihybrids
• Epistasis in coat color in mice - a genotype for
one gene alters the effect of the other gene
• aa = no pigment
production
• Regardless of
coat color gene,
mice is albino
57
Classwork:
Work on your reading guide or
practice packet
Incomplete Dominance
• Type of inheritance pattern where the
heterozygote is an intermediate or mix
between the dominant and recessive traits.
• Example – when a red carnation (RR) and a
white carnation (WW) are bred, a pink
carnation (RW) is produced.
• Use all capital letters since one isn’t
completely dominant over the other
RED x WHITE
RR x WW
So,
Genotypic ratio = 0:4:0
Phenotypic ratio = 0:4:0
100% pink
R
R
RW
RW
W
W RW RW
PINK X WHITE
RW x WW
So,
50% pink
50% white
R
W
RW
WW
W
RW
WW
W
Codominance
• Type of inheritance pattern when both alleles
are expressed in the heterozygote.
• Example – A brown cow (BB) and a white cow
(WW) produce a roan cow (BW) which is white
AND brown.
ROAN X ROAN
BW x BW
So,
25% brown
50% roan
25% white
B
W
BB
B
BW
BW
WW
W
Sex-linked trait
• Remember sex chromosomes determine an
individual’s gender.
• XX = female
• XY = male
• Sex-linked traits are only carried on (one of)
the sex chromosomes
• Since the X is larger, most sex-linked traits are
carried on the X and not the Y
– “X-linked”
• Traits must be symbolized using a superscript
on the X or Y, such as XR or Xr
Sex-linked traits
•
•
•
•
Fruit fly eye color
Red-green Color blindness
Hemophilia – blood clotting disorder
Duchenne's muscular dystrophy
Sex-linked Trait Practice
• Eye color is carried on the X chromosome in fruit
flies
• Red is dominant = XR
• White is recessive = Xr
• What are the possible female genotypes?
• XRXR , XRXr , XrXr
• What are the possible male genotypes?
• XRY or XrY
– Notice the Y doesn’t carry the trait; this makes sexlinked disorders more common in males because
they only need to inherit one allele rather than two
Cross a homozygous red eyed female
with a white eyed male
• The female’s genotype?
– XRXR
• The male’s genotype?
–
XR
XrY
So, now there is a 50%
chance of having a male
or female…
100% XRXr red females
100% XRY red males
r
X
Y
XR
XRXr
XRXr
XRY
XRY
PATTERNS OF HUMAN
INHERITANCE
Polygenic Traits
• “Many genes”
• Traits that are controlled by more than one
gene
• Most human traits are polygenic
• Examples
– Height
– Skin color
– Eye color
– Hair color
Skin Color Pigmentation
http://www.hhmi.org/biointeractive/biology-skin-color
Complex Characters
• Phenotype depends on the environment as well
as genes.
– “nature vs nurture”
• Examples
–
–
–
–
–
–
Malnutrition affects height
Exercise affects build
Sun exposure affects skin pigmentation
Experience affects intelligence
Tree leaf size and shape are affected by sun and wind
Even twins have phenotypic difference caused by
environment/experiences.
Multiple Allele Traits
• When more than two alleles determine a
trait, although an individual can still only
inherit two alleles.
• Examples
– Feather color in pigeons has 3 alleles
– Coat color in rabbits has 4 alleles
– Blood type in humans has 3 alleles
• Also shows codominance
Blood Type
A multiple allele trait
• The gene for blood type, gene I, codes for a
molecule that attaches to a membrane protein
found on the surface of red blood cells.
• Alleles IA and IB code for different molecules.
• Your body can recognize these proteins if they
belong to you.
Blood Type
• Possible alleles IA, IB, or i
– IA and IB are dominant to i
• There are 6 possible
genotypes (allele
combinations)
• There are 4 possible
phenotypes
– A, B, AB or O
• Blood typing shows
codominance when a
person inherits an allele
for A and B
Blood Type Punnett Square
Cross a homozygous type A with a heterozygous type B
Correct (AP) Way
Shorthand Way
IB
IA
IA IB
IA
IA IB
B
A
AB
A
AB
i
IA i
IA i
AO
O
AO
50% AB Heterozygous
50% AO Heterozygous A
Sex-influenced traits
• Traits in which males and females show
different phenotypes even though they have
the same genotype.
• Example – baldness, dominant in males,
recessive in women
• The differences are mainly due to males and
females producing different hormones.
Single allele traits
•
•
•
•
Traits where there is only one allele
If you have the allele, you have the trait
No recessive
Example – Huntington’s Disease
– Degenerative disease of the nervous system by
lethal dominant allele
– Located on Chromosome#4
– Can be detected with genetic testing
Classwork:
Complex Inheritance Practice
Date: 2/2/15
Objective: How do you interpret a pedigree?
QOD: None, please take out your notes packet
and your homework packet
Due today: CSI Lab
Agenda:
1.Review HW
2.Notes
3.Assign Project groups and topics
4.Homework
Homework: Next homework packet check is
tomorrow
Pedigrees
• Pedigree charts show a record of inherited
traits in a family
• They can be used to study or track the
transmission of a hereditary condition or
disease over generations
• They are particularly useful when there are
large families and a good family record over
several generations.
Pedigrees
Symbols used in pedigree charts
Normal male
Affected male
Normal female
Affected female
Marriage
A marriage with five children, two
daughters and three sons. The eldest
son is affected by the condition.
Eldest child  Youngest child
Pedigrees
• In pedigrees, carriers have one copy of the
recessive allele
– So they CARRY the trait, but they do not show it
– Symbol =
• Pedigrees can be used to make predictions
about future offspring or the genotype of
individuals in the pedigree
Pedigrees
• The first pedigree tracks the widow’s peak, so
the filled in shapes have a widow’s peak
– Widow’s peak is a dominant trait
• Carriers are not always shown on pedigrees
• Figure out the genotypes of the blank
individuals on the pedigree
– Think about what alleles their parents can give
them
#63
Ww
ww
ww
First generation
Ww (grandparents)
1
Ww ww ww Ww Ww ww
2
3
WW
or
Ww
Widow’s peak
Second generation
(parents plus aunts
and uncles)
Third
generation
(two sisters)
ww
No widow’s peak
Dominant trait (widow’s peak)
ww= no widow’s peak
85
WW= widow’s peak
Pedigrees
• The second pedigree tracks the attached
earlobes (a recessive trait), so the filled in
shapes have attached earlobes
• Figure out the genotypes of the blank
individuals on the pedigree
First generation
(grandparents)
Second generation
(parents plus aunts
and uncles)
Ff
FF or Ff ff
Ff
ff
Third
generation
(two sisters)
Attached earlobe
ff
Ff
Ff
ff
FF
or
Ff
?
ff
Free earlobe
Recessive trait (attached earlobe)
87
Organising the pedigree chart
• Generations are identified by Roman numerals
I
II
III
IV
Organising the pedigree chart
• Individuals in each generation are identified by
Arabic numerals numbered from the left
• Therefore the affected individuals are II3, IV2 and
IV3
I
II
III
IV
Date: 2/6/15
Objective: What are the different chromosomal
mutations?
QOD: A person who possesses an allele for a
trait, but doesn’t show the trait is called a
______.
Due today: Pedigree HW
Agenda:
1.Review HW
2.Notes
3.GMO Video
Homework: PROJECTS DUE MONDAY!
Remember not all mutations are bad…they can create new alleles for a
trait!
MUTATIONS
Mutations
• Mutations are changes in a DNA sequence
• Genetic disorders can occur if mutations to
the chromosomes occur before or during
meiosis.
• Offspring will carry the mutation in every cell
of their body.
Translocation
• When a piece of a chromosome breaks off and
reattaches to a non-homologous chromosome
Deletion
• The loss of a piece of a chromosome due to
breakage
• Can be caused by viruses, radiation, or chemicals
Deletion
• Cri du Chat, “cry of the cat,” is a disorder
cause by deletion of chromosome 5
– Infant’s cry is usually high-pitched
– Small at birth
– Respiratory problems
– Small head
– Round face, small chin
– Wide set eyes with folds of skin over eyes
Inversion
• A chromosome segment breaks off, flips
around, and reattaches
• Inversion can cause a clotting protein in
Hemophiliacs to not get produced
Nondisjunction
• When a chromosome fails to separate or
detach from its sister chromatid during
meiosis.
• Results in the addition or deletion of a
chromosome from a gamete
Effects of Nondisjunction
• Monosomy occurs when only one copy of a
pair is present (45)
• Trisomy occurs when three of a particular
chromosome is present (47)
• Many trisomys and almost all monosomys
are fatal.
Nondisjunction Abnormalities
• Trisomy 21 or Down Syndrome – extra 21st
chromosome – mental delay, fold of skin above eyes,
weak muscles, wide set eyes,
• Jacob Syndrome – XYY males – tall, acne, not overly
aggressive
• Turner Syndrome – XO females (missing X) – short,
webbed neck, absence of puberty, infertile, low set
ears and poor hearing
• Klinefelter Syndrome – XXY male (extra X)– mental
delay, low fertility, rare cases XXXY, XXXXY
• Triple X Female – XXX – no physcial abnormalities
Duplication
• When a gene sequence is
repeated one or more
times within a
chromosome.
• Fragile X Syndrome –
caused by duplication of a
gene on the X
chromosome
– Most common form of
autism and inherited
intellectual disabilities in
boys.
GENETIC DISORDERS:
DETECTION AND TREATMENT
Genetic Screening
• An examination of a person’s genetic makeup
• May involve studying a karyotype, blood tests
for certain proteins, or direct tests of DNA.
• Today, doctors can detect more than 200
disorders in a fetus
Genetic Screening
• Amniocentesis – procedure where amniotic
fluid is removed from the pregnant mothers
amnion (sac around fetus) during the 14-16th
week of pregnancy
• Chronic Villi Sampling – procedure in which
the chronic villi (cells from the zygote that
grow between the uterus and placenta) is
sampled and studied during the 8-10th week
of pregnancy
Genetic counseling
• The process of informing a person or couple
about their genetic makeup and what
problems might affect their offspring
• Many people with a family history of a genetic
disease seek counseling.
Gene Therapy
• In most cases, physicians treat only the
symptoms of genetic disease
– PKU – strict diet
– Cystic Fibrosis – breathing & back pounding
treatments
• Gene therapy would allow doctors to replace
a defective gene with a healthy copy of the
gene
Gene Therapy
• The location of the defective gene must be
known.
• A modified virus carrying the healthy gene would
be introduced to the patient’s affected area such
as the lungs with cystic fibrosis.
• The patient’s symptoms improve until the cells
die and the procedure is repeated.
• Researchers are working to increase the
effectiveness
• This is currently only done with somatic (body)
cells.
DNA TECHNOLOGY
DNA Identification
• Except for identical twins, no two people have
the same DNA.
• DNA identification compares DNA samples in
regions of a chromosome that differ.
• Useful for paternity tests, identification of
human remains, tracing human origins,
providing evidence in criminal cases.
Gel Electrophoresis
• Technique that separates DNA or proteins by
their size and charge allowing the fragments
to be studied
In Vitro Fertilization
• “In glass”
• In vitro fertilization in humans is the process
of fertilizing egg cells with sperm outside of
the human body
• The fertilized egg is then transplanted in the
uterus to grow normally.
Genetic Engineering
Genetic Engineering – the process of altering the
genetic material of cells or organisms to allow
them to make new substances
Artificial Selection or
Selective Breeding
• Breeding only those plants or organisms with
desirable traits.
• People have been using selective breeding for
thousands of years in agriculture and with the
domestication of animals.
Recombinant DNA
• Recombinant DNA is DNA created
from joining the DNA of two
different organisms.
• In 1982, insulin was the first
product made from recombinant
DNA that was used in bacteria
• Since then more than 30 products
have been approved worldwide
including many medically
important proteins to treat
hemophilia, growth defects, viral
infections, cancer, and more.
Cloning
• A clone is an exact copy
of a DNA segment, a
whole cell, or a
complete organism.
• 1997, Dolly the Sheep
• We want to be able to
make clones of
productive or healthy
animals to increase
yields on farms.
Cloning
• Dolly was an identical copy of her
mother created through the
process of reproductive cloning
• She was made by taking an egg
cells from a random sheep,
removing its nucleus, placing it
beside udder cell’s from Dolly’s
“mother” and passing an electric
charge between the two cells.
Stem Cell Technology
• A stem cell is an undifferentiated cell that can
develop and become specialized into different
types of cells.
– Embryonic stem cells
• Obtained from embryos
– Adult stem cells
• Body cells that can differentiate into some other cell types
– Induced pluripotent stem cells
• Body cells that have been induced to return to a stem-cell-like
state
• Right now stem cell therapy is still being
researched. When stem cells grow unregulated,
they can lead to cancers. Researchers are trying to
find ways to prevent this.
Genetically Modified Organisms
• GMO – any organisms whose DNA has been
altered by genetic engineering techniques
• Using recombinant DNA, organisms have
been produced with traits that can come
from adding the genes of another species
• Advances have allowed scientists to
manipulate, remove, and add genes to a
variety of different organisms to induce a
range of different traits.
• Many companies are producing and selling
genetically modified foods and medicines.
Vaccines & DNA Vaccines
• Vaccines contain all or part of a harmless version
of a pathogen that, when injected into the body,
creates immunity to disease.
– Our bodies respond by making defensive proteins called
anti-bodies, so if we ever encounter the disease again,
we are prepared to fight the infection.
• DNA vaccines are made with the DNA of the
pathogen without the disease-causing capabilities.
– If injected, our bodies would fight off the proteins the
DNA makes.
– If infected later on, immunity would provide protection.
• Researchers are currently trying to do this for AIDS,
malaria, and certain cancers.
Bioethics
• Bioethics is the study of ethical issues related to DNA
technology.
• Many different people are involved in addressing the
ethical, legal, and social issues that arise as we make
advancements in genetic engineering.
– Germline gene therapy and reproductive cloning are
currently viewed as unethical
– Regulations and safeguards on agriculture for GMOs
– Your genetic makeup should remain confidential to protect
you from discrimination in the workplace or elsewhere.
• We want to ensure that no tools turn out to be
dangerous or give unwanted results in the future.
• As you grow up in the 21st century, you may be asked
to vote as an informed citizen on bioethical issues.