DNA Technology

Please pick up notes on the front desk.

DNA Technology DNA technology is the exploitation of the knowledge of DNA and the genetic code for the purpose of industrial and medical applications in some cases ethical and in other cases unethical. This can only occur when biologists know exactly where particular genes for particular traits occur on specific chromosomes.

A gene map shows the relative location of each known gene on a chromosome. The Human Genome Project mapped the (90%) + DNA sequence and is useful for identifying genes of specific traits. Gene Map of human chromosome 3

So what can do some biologists do with this information?

Cloning Cloning is when an identical copy of a gene or an entire organism is produced. Cloning may occur naturally or may be engineered.

Naturally Occuring Identical twins have for the most part identical DNA and are considered to be clones. Many organisms and cells reproduce asexually and are therefore genetically identical.

Examples Bacteria – Division through binary fission produces two identical bacteria.

Sea stars clone themselves through regeneration.

Aspen reproduce through a process called suckering. The largest Aspen (and its clones) contains about 47,000 trees on about 100 acres.

Engineered Cloning 1997 Dolly was the first mammal to ever be cloned. Clones will never be identical behaviorally and may not even look 100% like one another. Environment plays an impact on development.

Cloning Opportunities Current studies are exploring how to use organs from cloned mammals for human transplants. Cloning may help save endangered species. Produce superior livestock or crops.

Cloning Controversy The success rate is very low. Hundreds of tries for one clone (and expensive). Clones may not be as healthy or live as long as the original (“old DNA”). Cloned animals in the wild will reduce genetic variability.

Stem Cells Undifferentiated stem cells have the potential to become specialized in structure or function. Therapy using stem cells can replace tissue that is deficient due to disease or damage.

Examples Stem cell skin grafts may now be used to replace conventional grafts.

Bone marrow transplants use healthy bone marrow stem cells to replace cancer producing ones in an individual with leukemia.

Genetic Engineering Manipulating DNA in organisms for a variety of reasons to achieve desired results.

Selective Breeding Classical breeding (inbreeding) process of artificially selecting and breeding organisms with desired traits to produce the next generation. Most crops and domesticated animals are a result of this.

The process works b/c in order for the parents to show strong expression for the trait, they must carry at least one gene for the trait. –Once the breeder has achieved this, inbreeding continues (crossing individuals who are closely related). –Over multiple generations, the gene for the trait will become more prevalent. –Problems- recessive gene defects show up after generations of inbreeding.

Hybridization A form of selective breeding in which two organisms that are different but similar species are crossed to get beneficial traits expressed by both. (white bass X striped bass)

Mules

What if? +

The Loch Nasquatch

Recombinant DNA DNA that contains genes from more than one organism. Recombinant DNA may be able to produce crops that make medicine and vitamins. A transgenic organism is one that has one or more genes from another organism inserted into its DNA.

Examples Transgenic bacteria make human insulin for Diabetes. Genetically Modified Crops

Genetically Modified Organisms Crops are genetically engineered to be resistant to particular insect pests. For example, toxin genes (Bt toxin) from a bacterium found in soil (Bacillus thuringiensis) are inserted into the crop DNA so that the plants produce toxins specifically deadly to the larvae of their pest insects. Soybeans have been genetically modified to resist herbicides that would normally kill them. Plants are genetically modified to ensure longer shelf life or greater resistance to frost. Farm animals (such as pigs, cows and chickens) are genetically modified for faster growth rates, leaner muscle-to-fat ratios or superior resistance to disease. Plants are modified to yield higher protein or nutrient levels, or produce healthier oils containing ‘functional food’ components such as omega 3 fatty acids. Genetically modified cows can produce milk that contains higher levels of bioactive milk proteins or human blood clotting components or a human breast milk component.

Bt Corn

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Gene Therapy Scientists insert a normal gene into an absent or abnormal gene. Once inserted, the normal gene begins to produce the correct protein or enzyme, eliminating the cause of the disorder. Often times the injected gene is rejected by the host.

Example Cystic Fibrosis patient inhaling healthy DNA.