Transcript Genetics 2 1314

Selective Breeding
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Selecting few organisms with desired traits
to be parents of the next generation
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Techniques
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Inbreeding: crossing two individuals with identical
or similar alleles to produce specific traits. This
can increase the chance of inheriting genetic
disorders...so you gotta be careful. Dogs breeders
and cattle folks do this.
Hybridization: crossing two individuals with
different traits, so offspring might get the
best traits of both. Used in agriculture.
Cloning
Clones are genetically identical to the
organisms from which they are produced.
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Plants: a horticulturist or botanist can cut a
small piece of plant, replant, and grow a new
plant
Animals: egg from one animal, has its nucleus
replaced with nucleus from another. This egg is
implanted in a third animal and gestated.
Genetic Engineering
The genes (specific segments of DNA) from one
organism are transferred into DNA sequence of
another. This is called “gene splicing.”
 Bacteria: insert DNA from another organism into
a bacterial cell. You get the bacteria to do the
work (such as manufacturing human insulin).
 Other organisms: we can take the genes from one
organism and insert them into another. Coolio…right?
“Like…how?” Like we can insert human genes for blood
clotting into cows, who in turn, produce blood clotting
factor (a protein). Then we can extract it and use it to treat
hemophilia.
…we’re so awesome  Well…ummm…sometimes
anyway.
Gene Therapy
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This is when genes are really depressed or angry
and need to talk to someone to “let it all out.” Did
you write that? Don’t you feel a little ridiculous?
The real skinny…We insert working copies of
gene into the DNA of people who have a
genetic disorder in hope that it will do the
job. For example…Insert a gene for certain
protein that ensures proper lung function into
a virus. The virus then produces the missing
protein. We “infect” an afflicted person with
the virus to help cure their cystic fibrosis.
It’s difficult and still being developed,
but…we’re gettin’ there…more cool points for
us.
The Human Genome Project
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Genome: all DNA in a cell of an organism
The goal was to identify each base-pair
sequence in human DNA (3,000,000,000) and
all 20-25 thousand genes.
Information leads to better understanding
and treatment/ prevention strategies
Finished in April 2003.
The real goal is to decode the human
PROTENOME…that’s all of our proteins…cuz
that’s the essence of what we are!
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The human genome contains 3164.7 million
nitrogenous bases (A, C, T, and G).
The average gene consists of 3000 bases, but
sizes vary greatly, with the largest known
human gene being dystrophin at 2.4 million
bases.
The total number of genes is estimated at
30,000
Almost all (99.9%) nucleotide bases are
exactly the same in all people.
The functions are unknown for over 50% of
discovered genes.
Less than 2% of the genome codes for
proteins.
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Mutations
When sumpin’ just ain’t right wit da DNA.
Many mutations are harmless…some…not so
much.
We’ve identified about 1.4 million locations where
mutations occur in our DNA. That’s almost as many
locations as Starbucks has.
This can help to find chromosomal locations
for disease-associated sequences and tracing
human history.
The ratio of gamete (sperm or egg cell) mutations is
2:1 in males vs females. Way to go guys.
Why the higher mutation rate in the male? Well a
few reasons including the greater number of cell
divisions required for sperm formation than for eggs.