3.5 Genetic Modification and Biotechnology Cloning 3.5 Genetic Modification and Biotechnology

Cloning the process of producing one individual that is genetically identical to another, using a single cell or tissue. CLONE: genetically identical organisms or cells derived from a single parent cell Remember: Cloning is a type of asexual reproduction.

Cloning Cloning occurs naturally in nature by both plants and animals (though is less common in animals)

Spore Formation Occurs in bacteria and mold The parent organism produces smaller cells called “spores” that can detach from the parent, land in another area and grow

Vegetative Propogation Occurs in many plants such as strawberries The plant produces a long stem-like feature called a “runner” that can detach from the plant and grow roots easily.

Budding Occurs in yeast and some multicellular organisms such as hydra. The organism grows and extensions, a “bud”, that eventually breaks off the parent.

Aphids In the spring female aphids can produce more female aphids that are essentially clones of themselves. In the fall, changes in their hormone levels causes them to produce males. Then male and female aphids can reproduce sexually.

Identical Twins They are an example of natural clones

Cloning Cloning can occur unnaturally as well. Humans have cloned plants for centuries and have recently begun cloning animals.

Plant Cloning WHY? Plants with favourable traits could be cloned (using vegetative propagation) to get: better tasting crops, better looking crops, larger crop yields, etc.

Animal Cloning It’s important to remember what cloning CANNOT do. Many people think that cloning a person will produce an individual of the same age. If humans were to be cloned, they would only reproduce a zygote, which then needs to be carried in a womb for nine months.

Cloning animals have traditionally been done by taking a fertilized egg (a zygote) and splitting it in half. This will produce a clone of the zygote (not of the parent). In this case, scientists have been able to create identical twins.

Cloning an adult mammal is MUCH more difficult In adults, all your cells are specialized to do specific jobs (for example: red blood cells, stomach cells, skin cells). It is very difficult to take a specialized cell and turn it back into a cell that is unspecialized (like those in zygotes).

Animal Cloning In July 1996, Ian Wilmut, a Scottish scientist, cloned the first mammal from an adult body cell – a sheep he named Dolly.

He first obtained an udder cell from a Finn Dorset sheep and removed the nucleus How did he do it?

He then obtained an egg cell from a Poll Dorset Sheep and removed the nucleus from the egg cell.

He placed the nucleus from the 1st cell (the Finn Dorset cell) into the egg cell of the Poll Dorset

To get this new cell to undergo cell division, he shocked it with electricity. He had to do this process ~277 times until it finally worked

Once the cell began dividing it formed an embryo. He implanted the embryo into the uterus of a Scottish Blackface Sheep The clone grew in the uterus of it until it was born. Dolly the sheep was a clone of the Finn Dorset Sheep.

Unfortunately, Dolly died prematurely at the age of 6 (half her lifespan) She displayed symptoms of premature aging, and such as arthritis and lung disease which is present in older sheep.

Many more species have been successfully cloned since Dolly, including goats, cows, mice, pigs, dogs, cats, rabbits, horses and camels, however, there are still many problems.

Why Clone Mammals? Cows that produce the most milk, hens that lay the most eggs, Cattle that produces the best tasting and beef can be cloned to make more organisms with the same desirable traits and create more financial profits.

If we could develop technologies to clone organs, it could solve problems related to lack of organ donors for sick individuals

Theraputic Cloning Involves stem cell research Aims at cell therapy – where diseased cells are replaced with health ones. Human embryos are produced (in vitro) and allowed to grow for a few days into a small ball of the cells. These cells are not yet specialised (they’re stem cells/ pluripotent)

Stem cells can also be obtained from umbilical cords or aborted fetuses. PURPOSE: Treat people suffereing from Parkinson’s Treat spinal cord injuries BONE MARROW – transplants for leukemia patients

Ethics of Therapeutic Cloning PRO: can cure and treat diseases with cell therapy

Ethics of Therapeutic Cloning CONS: Fear it can lead to reproductive cloning Creation and destruction of human embyros (“playing GOD”?) Embryonic stem cells are capable of many division and may turn into tumours.

GMOs: Genetically Modified Organisms Organisms whose genetic material has been altered to include specific genes, often from another species. If the GMO displays favourable characteristics it can be cloned to mass produce these favourable organisms.

Purpose of GMOs? Increase crop yields Increase shelf life Make disease and parasite resistant crops More nutritious crops Others?

Ex: Insulin Commercial Insulin (for diabetics) is produced by bacteria that has the gene for insulin inserted into its DNA

Flavr Savr 1994, the first GMO food do be sold commercially A tomato altered to stay fresh longer Contained a gene that blocked the production of an enzyme responsible for rotting

Golden Rice

Golden Rice Modified by adding genes from daffodils and bacterium Modified Rice now contains Vitamin A Many people in developing nations rely on rice as a major staple in their diet. Golden Rice provides more nutrition.

Bt Corn Inserted gene from the soil bacteria, Bacillus thuringiensis Causes the corn crops to produce a toxin making it resistant to insects.

Bt corn

Benefits of Bt Corn Reduces damage caused by the European Corn Borer (ECB) Less expensive than insecticide Less checking for effects of ECB Less insecticide – better for environment Less fungal infections

Harmful effects of Bt corn May kill other insects – influence food webs and ecosystems Insects may develop resistance to Bt toxin Which would make BT spray (insect repellent) ineffective for human use Pollen may get into another crop field, infiltrating organic crops and putting other ecosystems in jeopardy.

Cloning Endangered Species???

Problems with Clones lack of diversity/variation! The population of clones would be vulnerable to environmental changes and disease.

GM Crops Homework Read page 192-194 about the Risks and Benefits of GM crops Read “Analysing risks of monarch butterflies of Bt corn” on pg 194 and answer the corresponding data base question on page 195