Biotechnology. Breeding The first biotechnology Selective Breeding The breeding of organisms to...

Biotechnology

Breeding

•The first biotechnology

Selective Breeding

• The breeding of organisms to produce certain desired traits in their offspring

•Used to produce a new breed with a desired trait–Only the ones with the desired trait are selected to reproduce

Persian

Inbreeding• Crossing organisms that

have a similar genotype–Used to maintain a desired set of traits

–Can result in problems and undesirable traits (p. 207)

Sharpei

GermanShepherd

Outbreeding (hybridization)

• The crossing of distantly related organisms–Usually involves two breeds of the same species

Liger

Mule

Genetic Engineering

• Any technique used to identify or change genes at the molecular level

• Involves the building of Recombinant DNA–A molecule made from pieces of DNA from separate organisms

All genetic engineering experiments share 4

steps:•Cleaving DNA – a

desired gene is cut from DNA

•Producing Recombinant DNA – DNA fragment is put into the DNA of another cell

•Cloning cells – growing a large number of genetically identical cells from a single cell

•Screening cells – cells that received the gene of interest are identified and isolated

Example:• The gene for

human insulin can be isolated and inserted into a plasmid

• Bacterial cells then produce human insulin

• This is used by people who are diabetic

• Reduces the need for pig insulin which can cause allergic reactions

Transgenic Organisms•Organisms that contain genes from other species–Ex. Bacteria – gene for human insulin

–Ex. Mice with human immune genes to study immune system

Identifying Sequences in DNA

•DNA Fingerprint–DNA is cut into fragments by a restriction enzyme

• Because of differences in nucleotide sequences, the number of cutting sites for a restriction enzyme varies among the DNA of different individuals producing fragments of different lengths–The lengths are unique to each individual

• Samples are separated by a process called Gel Electrophoresisa. DNA fragments are dropped into thin slits in a track of gel

b. The gel tracks have a (+) charge at one end and a (-) charge at the opposite end

c. DNA has a (-) charge so the fragments move toward the (+) end of the gel

d. The smallest fragments move farthest along the tracks and the larger fragments stay toward the (+) end

e. A unique banding pattern is produced

f. Every person’s DNA has a unique pattern that can be used for identification

Cloning

•Clone: A member of a population of genetically identical cells produced from a single cell

•First cloned mammal – Dolly, the sheep

A donor cell is taken

from a sheep’s udder.

A donor cell is taken

from a sheep’s udder.Donor Nucleus

These two cells are fused using an electric shock

Fused CellEgg Cell

The nucleus of the egg cell is removed.

The fused cell begins dividing normally.

Embryo

The embryo is placed in the uterus of a foster mother.

Foster Mother

The embryo develops normally into a lamb—Dolly

Cloned Lamb

An egg cell is taken from an adult female sheep.

EXAMPLES OF BIOTECHNOLOGY IN

MEDICINE AND AGRICULTURE

• After listening to some of these examples of biotechnology in medicine and

agriculture, select three examples to include in your notes.

Making genetically engineered drugs

• The human gene for insulin can be inserted into bacteria so the bacteria produce human insulin–Human insulin is the first commercial product of genetic engineering

– Genetically engineered Factor VIII is used to treat hemophilia patients•This helps

blood to clot but is free of viruses (HIV and Hepatitis B) which could be in donated clotting factors.

Making genetically engineered vaccines

• Bacteria are genetically engineered to act as antibodies and are safer than using a weakened form of a disease-causing virus

• Helping treat the disease Cystic Fibrosis –Secretion of excess mucus in the lungs caused by a malfunctioning gene•This method has already had some success

•Healthy genes that have recombined with certain viruses or carrier cells can be delivered to lung cells via a nasal spray

•The healthy genes can replace the malfunctioning genes, correcting the genetic defect

Making crops resistance to herbicides and

insects• The gene that is resistant

to herbicides is inserted into plants

• The farmer treats the field with an herbicide and everything dies except the plants with the new gene

• Makes weed control easier

Making crops that need no fertilizer

• Genetically engineering crops to fix nitrogen

• Crops can be grown without adding fertilizer