Transcript Human Genetics

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Biotechnology
&
Bioethics
Should we or shouldn’t we?
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Biotechnology
The
application of scientific and
engineering principles to biological
agents to provide goods and services to
better human life
Many
moral issues today are centered
around genetic engineering via the
manipulation of DNA
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Ethics
Moral
philosophy
Discipline
concerned with
what is morally good and
bad, right and wrong
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Bioethics
Discipline
dealing with the
ethical implications of biological
research and the applications of
that research
Deals
with the questions relating
to the appropriate use of new
technologies
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There are no simple answers to ethical
dilemmas….
What will cause the
greatest good for
mankind?
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The Basics & More
A review
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23 Pairs = 46 TOTAL Chromosomes
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Autosome vs. Sex Chromosome
 Autosomes
-first 22
homologous pairs
 Sex
Chromosomes last pair
(23rd) that determine the sex
of an individual
+ Autosomal Traits
2 Types of Traits:
Autosomal
AA, Aa
Autosomal
aa
Dominant
carrier
Recessive
+ Sex-Linked Traits – on X
Typically Recessive
 Expresses Trait:
Male - Xa Y
Female - Xa Xa
 No
Male - XA Y
Female - XA XA
or XA Xa
Expression:
carrier
Cloning
GMO
DNA Fingerprint
Pedigrees
Karyotyping
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Biotechnology
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Karyotyping
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What are Chromosomal
Mutations?

Damage to chromosomes due to physical or chemical
disturbances or errors during meiosis.
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Two Types of Chromosome Mutations:
1.
Chromosome Structure
2.
Chromosome Number
+Problems
with Chromosome Structure:
1.
Deletion – during cell division, especially meiosis, a
piece of the chromosome breaks off, may be an end
piece or a middle piece (when two breaks in a
chromosome occur).
2.
Inversion – a segment of the chromosome is turned
180°, same gene but opposite position
3.
Translocation – movement of a chromosome segment
from one chromosome to a non-homologous
chromosome
4.
Duplication – a doubling of a chromosome segment
because of attaching a broken piece form a
homologous chromosome, or by unequal crossing
over.
+Problems
with Chromosome Number
Trisomy – having three of a particular type of
chromosome (2n + 1)
Monosomy – only one of a particular type of
chromosome (2n -1)
Polyploidy – having more than two sets of
chromosomes; triploids (3n = 3 of each type of
chromosome), tetraploids (4n = 4 of each type
of chromosome).
+How do you think Chromosomal
Mutations with differing number of
chromosomes develops?
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Monosomy and Trisomy due to Nondisjunction – members
of homologous chromosomes do not move apart in Meiosis I
or sister chromatids do not separate during Meiosis II leaves
one cell with too few chromosomes and one cell with too
many.
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Triploids develop from the fertilization of an abnormal
diploid egg, produced from the nondisjunction of all
chromosomes. Tetraploids develop from the failure of a 2n
zygote to divide after replicating its chromosomes,
subsequent mitosis would produce 4n embryo.
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Polyploidy is common in the plant kingdom, spontaneous
origin of polyploid individuals plays important role in
evolution of plants. In the animal kingdom, natural
occurrence of polyploids is extremely rare. In general,
polyploids are more nearly normal in appearance than
having monosomy or trisomy, which is more disruptive to
have one extra chromosome in a pair.
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Pedigrees
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Pedigree –genetic family tree
Symbols and Rules:
 Male
=
 Affected
 Link
Female =
=
Unaffected =
Carrier =
parents together with a line and then make a
vertical line to connect to offspring.
+ Autosomal Dominant Pedigree
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Draw a Pedigree showing a cross between Heterozygous parents
that have 2 boys and 2 girls.
Genotypes of Affected and Unaffected:

AA and Aa = Affected
aa = Unaffected
Aa
aa
Aa
Aa
Aa
AA
+ Autosomal Recessive Pedigree
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Draw a Pedigree showing a cross between Heterozygous
parents that have 2 boys and 2 girls.
Genotypes of Affected and Unaffected:
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AA=Unaffected Aa=Carrier, Unaffected aa=Affected
Aa
aa
Aa
Aa
Aa
AA
+ Sex-Linked Recessive Pedigree
 Draw
a Pedigree showing a cross between a
Red eyed Male fruit fly and a Carrier Female
fruit fly which have 2 males and 2 females. Red
is dominant to white.
Genotypes of Parents:
Male = XR Y
Female = XR Xr
XRY
XRY
XRXr
XrY
XRXR
XRXr
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Autosomal Dominant Traits
 Heterozygotes
 Affected
are affected
children usually have affected parents.
 Two
affected parents can produce an unaffected
child. (Aa x Aa)
 Two
unaffected parents will not produce affected
children. (aa x aa)
 Both
males and females are affected with equal
frequency.
 Pedigrees
show no Carriers.
+ Autosomal Recessive Traits
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Heterozygotes are Carriers with a normal phenotype.

Most affected children have normal parents. (Aa x Aa)
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Two affected parents will always produce an affected child.
(aa x aa)
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Two unaffected parents will not produce affected children
unless both are Carriers. (AA x AA, AA x Aa)
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Affected individuals with homozygous unaffected mates will
have unaffected children. (aa x AA)
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Close relatives who reproduce are more likely to have
affected children.
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Both males and females are affected with equal frequency.

Pedigrees show both male and female carriers.
+ Sex-Linked Recessive Traits
 More
males than females are affected.
 An
affected son can have parents who have the
normal phenotype. (XAY x XAXa)
 For
a daughter to have the trait, her father must also
have it. Her mother must have it or be a carrier.
(XaY, XaXa, XAXa)
 The
trait often skips a generation from the
grandfather to the grandson.
 If
a woman has the trait (XaXa), all of her sons will
be affected.
 Pedigrees
carriers.
show only female carriers but no male
Autosomal Dominant Disorders
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Dwarfism
Polydactyly and
Syndactyly
Progeria
+ Autosomal Recessive Disorders
Congenital Deafness
Sickle Cell anemia
Albinism
+Sex-Linked Recessive Disorders
Red/Green Colorblindness
Hemophilia
Deafness
Cataracts
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DNA
Fingerprinting
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DNA Fingerprint
DNA
fragments show unique patterns from
one person to the next.
Used
in paternity disputes and as forensic
evidence.
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RFLPpieces of DNA cut up by enzymes
Restriction Fragment Length Polymorphism (RFLP)
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Nucleotide sequence variations in a region of DNA that
generates fragment length differences according to the
presence or absence of restriction enzyme recognition sites.
Gel Electophoresis
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RFLP animation
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Diagnose Disease
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Paternity Testing
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Forensics
DNA Fingerprinting
Animation
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Genealogy
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Genealogy
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Cloning
Making an EXACT
copy of an
individual
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Reproductive Cloning
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Creating a genetically identical organism
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Many animals have been successfully cloned
Cloning
How it is done
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Industrial Cloning
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http://www.bbc.com/news/science-environment-25576718
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Therapeutic Cloning
 Cloning
Individual Human Cells
 Involves
Stem cells – precursor cells that give rise
to specialized cells/multiple tissue types
 Allows
organs
for the generation of human tissue and
 Enhances
our understanding of human
development and serious medical conditions
(cancer, birth defects, etc)
 Embryonic
vs Adult Stem Cells
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Have we made a Human Clone?
NOT YET
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VIDEO
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Eugenics
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An effort to breed better human beings
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Encourage “good genes”
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Discourage “bad genes”
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Fear of history –
Sterilization of the mentally ill in early America
Nazi concentration camps
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Genetic Testing
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Individual risk assessment based upon a person’s DNA
profile
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DNA chip identifies genetic predispositions
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Potential for genetic discrimination
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DNA profiling? DNA banks?
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PreImplantation Genetic Diagnosis
(PGD)
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Diagnosing inherited genetic disorders “in vitro”
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Choosing which embryos will be transferred to the uterus based
upon desired traits
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Gender decisions
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“Designer Babies?”
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Are Designer Babies Real?
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GMO
Genetically
Modified Organisms
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How GMOs are made:
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Transgenic Plants
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Engineered plants that contain novel genes from other
species
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Results in new characteristics that make plants more
desirable and useful to humans
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GMO Foods Video
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Are they safe to eat?
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How do they affect the ecosystem?
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Transgenic Animals
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Engineered animals that contain novel genes from other
species
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Results in animals that are more desirable and useful to
humans
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Goats VIDEO
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Are they safe to eat?
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Where do we draw the line?
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Xenotransplantation
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Harvesting organs from animals for organ transplantation
into humans
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Severe Organ donor shortage
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Pigs – Perfect match!
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Do we have the right? PETA
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Dangers of Creating New Human Viruses
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Video
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Finding a Balance
Focusing on whether or not “we could”
Instead of whether or not “we should”
Weighing the Pros versus the Cons
Acknowledging the tremendous
responsibilities that must be faced with the
information that we have acquired.