APPLIED GENETICSAPPLIED GENETICS

Humans have been using the concept of Humans have been using the concept of inheritance long before they understood inheritance long before they understood

modern genetics. Now that we have a better modern genetics. Now that we have a better understanding we have gone quite a few understanding we have gone quite a few

steps further.steps further.

Selective BreedingSelective Breeding

Choosing the organisms with the most Choosing the organisms with the most desirable traits for mating. The only way desirable traits for mating. The only way this is possible is if all organisms of the this is possible is if all organisms of the same species are not the same.same species are not the same.

Variation = inherited differences Variation = inherited differences

For example:For example:Dairy cows. Joe-bob-jimbo the farmer wants cows that Dairy cows. Joe-bob-jimbo the farmer wants cows that

produce enormous quantities of milk. He recognizes that produce enormous quantities of milk. He recognizes that some cows, for whatever reason (but if they’re not some cows, for whatever reason (but if they’re not genetic reasons this won’t work) produce more milk than genetic reasons this won’t work) produce more milk than others. Each breeding season he only breeds those cows others. Each breeding season he only breeds those cows that produce lots of milk hoping their calves will inherit that produce lots of milk hoping their calves will inherit their mom’s enormous milk-making abilities. Eventually, their mom’s enormous milk-making abilities. Eventually, Joe-bob-jimbo will have cows that produce mucho milk. Joe-bob-jimbo will have cows that produce mucho milk.

When the individuals chosen for mating are closely When the individuals chosen for mating are closely

related it’s called related it’s called inbreedinginbreeding

Hybridization:Hybridization: This is mating two different This is mating two different

species together. species together. Sometimes this makes Sometimes this makes for a hardier organism. for a hardier organism. The classic example is The classic example is the mule. The mule is the mule. The mule is stronger and more stronger and more durable than either the durable than either the horse or the donkey (the horse or the donkey (the parent species). The parent species). The problem is, due to problem is, due to chromosomal chromosomal mismatching, most mismatching, most hybrids are sterile. hybrids are sterile.

Genetic Engineering:Genetic Engineering:

This involves the actual This involves the actual manipulation of genes manipulation of genes

Step 1. Isolate the desired gene. Step 1. Isolate the desired gene.

Step 2. Combine that gene with the new Step 2. Combine that gene with the new organism’s DNAorganism’s DNA

Step 3. Insert the combined DNA into the Step 3. Insert the combined DNA into the organism.organism.

Recombinant DNARecombinant DNA

Because a section of DNA is cut out of one Because a section of DNA is cut out of one genome and the genome and the combinedcombined with another with another genome it is referred to as:genome it is referred to as:

RECOMBINANT DNARECOMBINANT DNA

Because the process is so similar to video and Because the process is so similar to video and audio tape splicing, this type of genetic audio tape splicing, this type of genetic

engineering is called engineering is called Gene Splicing.Gene Splicing.

BiosteelBiosteel

Genetic engineers in Plattsburg, NY have spliced the Genetic engineers in Plattsburg, NY have spliced the gene for the protein that makes up spider’s silk into gene for the protein that makes up spider’s silk into goat zygotes (zygoats?).goat zygotes (zygoats?).

Ounce per ounce, spider’s silk has more tensile Ounce per ounce, spider’s silk has more tensile strength than steel.strength than steel.

When the spider’s gene is expressed in goats they When the spider’s gene is expressed in goats they don’t spin webs and swing around the city fighting don’t spin webs and swing around the city fighting crime (Spidergoat, spidergoat, does whatever a crime (Spidergoat, spidergoat, does whatever a spidergoat does)spidergoat does)

BiosteelBiosteel

Instead, the silk protein is secreted in the Instead, the silk protein is secreted in the milk of the goat. The goats are milked and milk of the goat. The goats are milked and the protein separated from the rest of the the protein separated from the rest of the milk.milk.

The protein is used instead of Kevlar in The protein is used instead of Kevlar in bullet-proof vests and other applications bullet-proof vests and other applications needing strength and flexibility.needing strength and flexibility.

HumulinHumulinSome people lack a functional gene for insulinSome people lack a functional gene for insulin

Made in the pancreas, allows cells to take up glucose

Supplemental insulin was provided by taking it from camels and sheep

That makes the sheep and camels grumpy and dead.

Plus, some people were allergic or sensitive to camel and sheep proteins.

HumulinHumulinEnter Enter E. coliE. coli

They’re a little bit easier to grow than goats

We splice the gene for human insulin from a human cell.

We turn the strand of DNA into a loop called a plasmid.

Bacteria are quite used to taking up plasmids into their own genome so this is very easy.

Now we have a bacteria that can synthesis human insulin!

Makes for much happier camels!

Humulin on the Regents ExamHumulin on the Regents Exam