Humans, Biotechnology,

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Humans, Biotechnology, And Genetic Disorders
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Old Uses of Biotechnology
Before modern genetics, human biotechnology was
limited to the science of selective breeding --
Selective breeding is where people crossed the
best traits of two organisms in the hope to get
a new organism with multiple desirable
traits -- like a farmer crossing his
best-tasting and largest-growing tomato plants
to make great- tasting large tomatoes -- was
also done inter-species Today, modern genetics
and biotechnology can be used to do things like
DNA profiling using RFLP, and gene therapy
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Gene Therapy
Gene Therapy is an attempt to cure genetic
disease by replacing diseased genes with
healthy ones -- there have been some successes,
like the treatment of hypercholestemia by gene
therapy in liver cells -- there have also been
many failures, often resulting in death when
genes get knocked out WHAT FOLLOWS IS A LIST
OF GENETIC DISORDERS THAT YOU ARE RESPONSIBLE TO
KNOW
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Cystic Fibrosis (CF)
Cystic fibrosis is caused by an autosomal
recessive allele The result is the excess
production of mucous in the lungs and digestive
tract, due to lack of production of certain
enzymes Tends to run in Caucasian populations,
particularly of European descent There is no
treatment, just therapies such as drugs that
break down excess mucus. Often, lung transplants
are necessary The disease gets more severe as
victims age, usually resulting in death by the
late 20s or early 30s
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Sickle-Cell Anemia
Sickle-cell anemia is caused by a codominant
autosomal allele Individuals with sickle-cell
anemia have red blood cells that bend (or
sickle), making it so that the hemoglobin is
unable to carry as much oxygen Red blood cells
tend to stick together or clot in veins and
arteries Tends to run in populations of African
descent, as heterozygous conditions provide
relief from malaria Many blood transfusions are
necessary throughout a lifetime, and individuals
tend to have a short lifespan
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Phenylketonuria (PKU)
PKU is caused by a recessive autosomal
allele Individuals with PKU are missing an enzyme
that allows for the digestion of the amino acid
phenylalanine Over time, phenylalanine
accumulates in the nervous system causing severe
retardation and death If diagnosed early, a diet
avoiding phenylalanine can prevent the symptoms
of this disease -- the diet can be stopped when
the nervous system is fully developed
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Tay-Sachs Disease
Tay-Sachs disease is caused by a recessive
autosomal allele In Tay-Sachs, individuals have
an inability to break down lipid molecules This
leads to degradation of the nervous system,
blindness, seizures, and eventually death,
usually before age 5 Tends to run in populations
of European descent, especially Ashkenazi
Jews There is no treatment or cure
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Huntingtons Disease
Huntingtons Disease is caused by an autosomal
dominant allele Around age 40, the nervous system
begins to degrade, eventually leading to
blindness, seizures and death Because this
disease has an onset after reproductive age and
is dominant, parents have a 50 chance of passing
the allele onto offspring There is no cure for
Huntingtons Disease (also called Huntingtons
Chorea)
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Hemophilia
Hemophilia is caused by a recessive sex-linked
allele In hemophilia, the blood is missing one of
its clotting-factor proteins and does not clot,
leading to excessive bleeding and eventually
death There is no cure for hemophilia, but with
careful monitoring and treatment, hemophiliacs
can live a long life
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Nondisjunction Disorders
Nondisjunction disorders can be spotted using a
karyotype Downs Syndrome (Trisomy 21) mental
retardation, long life possible Turners Syndrome
(XO) undeveloped female, usually
sterile Klinefelters Syndrome (XXY)
underdeveloped male, can be sterile
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Other Disorders . . .
Marfans Syndrome
Achondroplasia