Transcript Biology Today (BIOL 109)

An Ecological Perspective
(BIOL 346)
Talk one:
Biological Ethics
Perspective on What, exactly?
• Identify the structure, function, and processes of
ecosystems
– the physical environment and biological community of which
human society is a part and on which it depends.
• The environmental problems Humans have created.
• What natural resource challenges are being addressed by
the social, legal, economic, political, cultural, and religious
systems within societies.
• And, of course, the concept of Sustainability
– What? Why? How? Ethical issues involved!
• Ethics:
Ethics
– also known as moral philosophy, is a branch of philosophy that
involves systematizing, defending, and recommending concepts of
right and wrong conduct.
• Most people confuse ethics with behaving in accordance
with social conventions, religious beliefs, and the law, and
don't treat ethics as a stand-alone concept.
• Ethics can be defined as "a set of concepts and principles
that guide us in determining what behavior helps or
harms sentient creatures.”
– Paul, Richard; Elder, Linda (2006). The Miniature Guide to
Understanding the Foundations of Ethical Reasoning.
Bioethics
• The study of controversial ethics brought about by
advances in biology and medicine.
• Bioethicists are concerned with the ethical
questions that arise in the relationships among:
– Life sciences, biotechnology, medicine, politics, law,
and philosophy.
• It also includes the study of the more commonplace
questions of values ("the ethics of the ordinary")
that arise in primary care and other branches of
medicine.
Bioethics
• Also needs to address emerging biotechnologies
that affect basic biology and future humans.
• These developments include:
–
cloning, gene therapy, human genetic engineering,
astro-ethics and life in space, and manipulation of
basic biology through altered DNA, and proteins.
• Correspondingly, new bioethics
address life at its core.
also
need
to
– For example, biotic ethics value life itself and seek to
propagate it.
• With such life-centered principles, ethics may secure a
cosmological future for life.
Geoethics
• Deals with the way of human thinking and acting in
relation to the significance of the Earth as a
system and as a model.
• Scientific, technological, methodological and socialcultural aspects are included, e.g.:
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Sustainability and development.
geo-diversity and geo-heritage.
prudent consumption of mineral resources.
appropriate measures for predictability and mitigation
of natural hazards.
– geoscience communication.
• So:
Ethics
• Concepts of right and wrong conduct are clearly very
important for:
– Any scientific study
– Addressing and implementing policies of change:
• In an ideal world these ethical concepts would have, and
continue to, guide us as our understanding of science
increased.
• OOOPS!!!!!!!!!!!!
Scientific theories
• Animals, plants, and bacteria are examples of living systems
that share many properties distinguishing them from
nonliving things. These properties are branched into
theories.
Cellular organization
Fundamental unit of life is the cell – all living things are
made up of cells.
Metabolism
Living things take up energy-rich materials and give out
waste to environment. Some energy fuels life processes
some accumulates and is released after death.
Selective response
Living things respond selectively to stimulation in the
environment. Organisms recognize certain chemicals as
nutrients while ignoring others.
Scientific theories
Homeostasis
Living systems have some capacity to change harmful conditions
into conditions more favorable to their continuing existence – the
conversion of chemical compounds.
Growth and biosynthesis
Living systems go through phases during which they make more of
their own material.
Genetic material
Living systems contain genetic material (DNA and RNA) to allow
inherited traits.
Reproduction
Living systems can reproduce & pass on genetic material.
Population structure
Organism form populations. Of these organism capable of sexual
processes, a population is all those organisms that can interbreed
with one another.
Paradigms
• A paradigm is much more than a theory
– It includes a strong belief in the truth of one or more
theories and shared opinions as to what problems are
important and unimportant
– What techniques and research methods are useful
• Over time a paradigm shift occurs
– Better technologies and scientific instruments lead
scientists to look and old data in a different way
– Younger scientists look at old data in a new way
– In this way ideas and definitions of theories alter over
time an new data is collected and explained.
Paradigm Shifts
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OLD PARADIGM
Natural Theology, Lamarckism, and
several other competing paradigms
Blending inheritance and various folk
ideas
Various beliefs: bad humors, bad air
or water, evil spirits, and many others
Competing paradigms, including
Darwinism, mutationism, population
genetics, neo-Lamarckism
Classical Mendelian genetics
Various theories of territorial
behavior, sexual behavior, etc.; also
psychological theories (gestalt,
behaviorism, ethology)
Descartes’ mechanistic theories and
dualism
Classic germ theory: pathogenicity as
a characteristic of pathogen only
NEW PARADIGM
Darwinism (since 1859)
Classical Mendelian genetics (since 1865
or 1900)
Germ theory of disease (Pasteur, Koch,
since 1880)
Modern evolutionary theory (since
1940)
Molecular genetics (since 1950s)
Sociobiology (since 1975)
Mind–body connections (since 1980s)
Pathogenicity as an interaction of
pathogen and host (since 1990s)
Science has Improved our
Lives!
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Antibiotics--Penicillin, others?
Vaccines--Polio, Measles, Smallpox, others?
Cell Biology--Cancer Research, others?
Genetics--Basis for Disease, others?
Physics--Electricity!, others?
Engineering--Roads, Bridges, Buildings,
Planes, Trains, Bikes, others?
• Fermentation--Civilization!
Science has also opened up
“Pandora’s Box”
• Bio-warfare-, Anthrax letters, Current
worries?
• Nuclear Weapons--Does North Korea
really have them?
• Genome--Insurance issues, Selecting
offspring?
• Others?
Ethical thinking
• Ethics is a discipline
dealing with the analysis
of moral rule and the
ways in which moral
judgments are made and
justified.
• Would you park your car
in this space?
• Why?
Ethical thinking
• What benefits could
come from nuclear
power?
• At what cost?
• At what risk?
• Remember Chernobyl?
Chernobyl Nuclear Disaster
• April 26, 1986 in the Ukraine,
• It is regarded as the worst
accident in the history of nuclear
power.
• A plume of radioactive fallout
drifted over parts of the western
Soviet Union, Eastern and
Western Europe, Scandinavia, the
British Isles, and eastern North
America. Large areas of Ukraine,
Belarus, and Russia were badly
contaminated
• Resulted in the evacuation and
resettlement of over 336,000
people. About 60% of the
radioactive fallout landed in
Belarus, according to official
post-Soviet data
Chernobyl Nuclear Disaster
• Two hundred people were hospitalized
immediately, of whom 31 died (28 of
them died from acute radiation
exposure).
• Most of these were fire and rescue
workers trying to bring the accident
under control
• At least 8,000 people have died, most
from radiation-related diseases.
• About 2,000 people have been
diagnosed with thyroid cancer and
between 8,000 and 10,000 cases are
expected to develop over the next 10
years.
Chernobyl Nuclear Disaster
Rights
• Do animals have rights?
• Nearly all new drugs,
cosmetics, food additives,
new forms of surgery are
tested on animals first
• Many societies have
historically denied even the
most basic of rights to
classes of persons on the
basis of economics, gender,
race, ethnicity, or religious
beliefs
Experiments without consent
• Humans as experimental subjects
• Experiments on twins
• Bone, muscle, and nerve transplantation
experiments
• Head injury experiments
• Freezing experiments
• Malaria experiments
• High Altitude and pressure experiments
Experiments without consent
• 1932 The Tuskegee Syphilis Study
begins.
• 200 African-American men infected with
syphilis are never told of their illness, are
denied treatment, and instead are used as
human guinea pigs in order to follow the
progression and symptoms of the disease.
Charlie Pollard
• 95% all subsequently die from syphilis,
their families never told that they could
have been treated.
• Voluntary informed consent
– Both a moral and legal issue
• As there are lawyers under every rock!
Herman Shaw
Thalidomide
• Gender bias
– What happens if this is not
considered
– It was only in 1992 that
women were included in
medical trials of new drugs
by law!
• Thalidomide (Kevadon®)
– Developed as a morning
sickness drug in the 1950s
– BUT – never tested on women
• Led to a generation of
deformities
Thalidomide – how did it affect
DNA?
DNA structure:
• Composed of 4
nucleotide bases, 5
carbon sugar and
phosphate.
• Base pair = rungs of a
ladder.
• Edges = sugarphosphate backbone.
• Double Helix
• Anti-Parallel
DNA Replication
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Adenine (A) always base pairs with thymine (T)
Guanine (G) always base pairs with Cytosine (C)
ALL Down to HYDROGEN Bonding
Requires steps:
– H bonds break as enzymes unwind molecule
– New nucleotides (always in nucleus) fit into place
beside old strand in a process called Complementary
Base Pairing.
– New nucleotides joined together by enzyme called
DNA Polymerase
Central Dogma of Molecular
Biology
So, how did Thalidomide affect
DNA?
• Regulation of gene expression:
– Gene transcription begins with the enzyme RNA polymerase binding
to a promoter sequence.
– Allows transcription to occur DNA – RNA - protein
So, how did Thalidomide affect
DNA?
• When the polymerases stays attached to the promoter
longer more copies are transcribed
• On the DNA near the promoter there are regulatory gene
sequences called enhancers.
– Enhancers cause polymerase to bind more tightly and more gene
expression occurs
So, how did Thalidomide affect
DNA?
• If repressors bind to the regulatory sequences RNA
polymerase is blocked from the promoter and transcription
is halted.
• Thus gene expression stops
So, how did Thalidomide affect
DNA?
• So, things to remember:
• All genes are coded for at the genetic level by four
nucleotide bases (A, C, G, and T) and each gene has
a unique coding and relative ratio of these bases.
• Gene expression is highly regulated:
– Promoters, enhancers, and repressors
• In limb development, the genes involved have a
VERY HIGH relative ratio of guanine (G).
Thalidomide
• The structure of thalidomide
is similar to that of the DNA
purine bases adenine (A) and
guanine (G).
• In solution, thalidomide binds
more readily to guanine than
to adenine, and has almost no
affinity for the other
nucleotides, cytosine (C) and
thymine (T).
• Furthermore, thalidomide can
intercalate into DNA,
presumably at G-rich sites.
Thalidomide
• Thalidomide or one of its
metabolites intercalates into
these G-rich promoter regions,
inhibiting the production of
proteins and blocking
development of the limb buds.
• This intercalation would
significantly affect the genes
that rely primarily on guanine
sequences.
• Most other developing tissues
in the embryo rely on pathways
without guanine, and are
therefore not affected by
thalidomide
Thalidomide
• In UK alone there were
12,000 victims.
• Sometimes functional feet
and hands were amputated to
allow the fitting of lower- and
upper-limb Prosthesis in
order for the children to
appear “normal”.
• Special school were set up
too, in an attempt to keep the
children out of sight and out
of the minds of the public.
Thalidomide
• Victims of the 1970s
Thalidomide scandal have
passed their deformities on
to their children.
• Turns out that Thalidomide
altered the DNA of the
victims – so arms and legs
are not developed!
Thalidomide, Still?!!!!!!
• Still in use today
• Cancer treatments
– by cutting off the flow of blood
to tumors
• Leprosy
– is an infectious disease caused by
a DNA plasmid
– invades human nerves.
– If untreated can eventually cause
a variety of skin problems, loss of
feeling, and paralysis of the
hands and feet
.
Genetically modified crops
• All plant characteristics, such as size, texture, and
sweetness, are determined on the genetic level.
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Also:
The hardiness of crop plants.
Their drought resistance.
Rate of growth under different soil conditions.
Dependence on fertilizers.
Resistance to various pests and diseases.
• Used to do this by selective breeding
Genetically modified crops
• Agrobacterium method
– Uses the natural infection mechanism of
a plant pathogen
– Agrobacterium tumefaciens naturally
infects the wound sites in
dicotyledonous plant causing the
formation of the crown gall tumors.
– Capable to transfer a particular DNA
segment (T-DNA) of the tumor-inducing
(Ti) plasmid into the nucleus of infected
cells where it is integrated fully into
the host genome and transcribed,
causing the crown gall disease.
• So the pathogen inserts the new DNA with
great success!!!
What people think of using GM Plants!
• Survey carried out by:
– The Scientist Magazine.
• Feb 2004, No/15401
• 302 readers responded to survey
• Yes, a small group, as there are
seven billion people on the planet
• Interesting questions!
• What to YOU think?
Genetically modified crops
• Issues:
• Destroying ecosystems – tomatoes are now
growing in the artic tundra with fish antifreeze
in them!
• Destroying ecosystems – will the toxin now
being produced by pest-resistance stains kill
“friendly” insects such as butterflies.
• Altering nature – should we be swapping genes
between species?
Genetically modified crops
• Issues:
• Vegetarians – what about those tomatoes?
• Religious dietary laws – anything from a pig?
• Cross-pollination – producing a super-weed
• Human health – what of the antibiotic marker
gene?
The End.
Any Questions?