Download Human Molecular Genetics

Human Molecular Genetics
Tools of Molecular Biology
In genetic engineering, biologists make changes
in the DNA code of a living organism.
DNA Extraction: cells are opened and the DNA is
separated from the other cell parts
Cutting DNA: biologists cut them into smaller
fragments using restriction enzymes
Separating DNA: Gel Electrophoresis separates
DNA fragments according to their size.
Human DNA Analysis
1. Testing for alleles: DNA testing can pinpoint
the exact genetic basis of a disorder.
2. DNA Fingerprinting: analyzes sections of
DNA that have little or no known function
but vary widely from one individual to
another
DNA Fingerprinting
Chromosomes contain large
amounts of DNA called
repeats that do not code
for proteins.
This DNA pattern varies
from person to person.
Restriction enzymes are
used to cut the DNA into
fragments containing
genes and repeats.
DNA Fingerprinting
DNA fragments are separated
using gel electrophoresis.
Fragments containing repeats
are labeled.
This produces a series of
bands—the DNA fingerprint.
The Human Genome Project
The Human Genome Project is an ongoing effort to
analyze the human DNA sequence.
– In June 2000, a working copy of the human genome
was essentially complete.
– Research groups are analyzing the DNA sequence,
looking for genes that may provide clues to the basic
properties of life.
– Biotechnology companies are looking for information
that may help develop new drugs and treatments for
diseases.
Gene Therapy
In gene therapy, an absent or faulty gene is
replaced by a normal, working gene.
The body can then make the correct protein or
enzyme, eliminating the cause of the disorder.
Gene Therapy
A DNA fragment containing
a replacement gene is
spliced to viral DNA.
The patient is then infected
with the modified virus
particles, which should
carry the gene into cells
to correct genetic
defects.
The aim of today's gene technologies is
to introduce, enhance or delete
particular characteristics of a living
thing, depending on whether they are
considered desirable or undesirable.
Applications of Genetic Engineering
Transgenic Organisms
• An organism described as transgenic,
contains genes from other species.
How are transgenic organisms useful to
human beings?
Transgenic Organisms Benefits
-
Insect resistant crops
Virus resistant
Herbicide tolerant
Tolerant to environmental conditions (frost,
drought
Transgenic Animals
• Transgenic animals have been used to
study genes and to improve the food
supply.
– Mice have been produced with human genes
that make their immune systems act similarly
to those of humans. This allows scientists to
study the effects of diseases on the human
immune system.
– Researchers are trying to produce transgenic
chickens that will be resistant to the bacterial
infections that can cause food poisoning.
Transgenic Plants
• Transgenic plants contain a gene that
produces a natural insecticide, so plants
don’t have to be sprayed with pesticides.
Cloning
• A clone is a member
of a population of
genetically identical
cells produced from a
single cell.
• In 1997, Ian Wilmut
cloned a sheep
called Dolly.
• Animation
Dolly and Bonnie
Cloning
• Cloning Dolly
Donor Nucleus
Fused cell
Egg Cell
Embryo
Cloned
Lamb
Foster Mother
The Future of Cloning
• Researchers hope cloning will enable
them to make copies of transgenic animals
and help save endangered species.