Biotechnology

Dolly and surrogate Mom

Genetically modified rice.Embryonic stem cells and gene therapy

Biotechnology

Biotechnology is the engineering of organisms for useful purposes.

Usually involves the creation of hybrid genes and their introduction into organisms in which some or all of the gene is not normally present.

Fourteen month-old genetically engineered (“biotech”) salmon (left) and standard salmon (right).

Biotechnology

We’ll examine:

Animal cloning

Gene cloning for pharmaceutical production

The promise and perhaps perils of embryonic stem cells

DNA fingerprinting

Genetically modified foods

Animal Cloning

Dolly and her surrogate mother 1997

Why Clone Animals?

To answer questions of basic biology

Five genetically identical cloned pigs.

For herd improvement. To satisfy our desires (e.g. pet cloning).

For pharmaceutical production.

Is Animal Cloning Ethical?

The first cloned horse and her surrogate mother/genetic twin.

As with many important questions, the answer is beyond the scope of science.

1. Researchers isolated a somatic cell from an adult female sheep

2. Transferred the nucleus from that cell to an egg cell from which the nucleus had been removed

3. The egg cell, with its new nucleus, was behaving just like a freshly fertilized zygote

4. It developed into an embryo, which was implanted into a surrogate mother and carried to term.

Video

The Biotechnology of Reproductive Cloning

Saved by Cloning?

Some are firm believers while many view these approaches to be more of a stunt.

Article

(Science (2002) 295:1443)

Carbon Copy– the First Cloned Pet

The Next Step?

Attempts at human cloning are viewed very unfavorably in the scientific community.

Recombinant DNA, Gene Cloning, and Pharmaceutical Production

DNA can be cut at specific sequences using restriction enzymes.

This creates DNA fragments useful for gene cloning.

Restriction Enzymes are Enzymes That Cut DNA Only at Particular Sequences

The enzyme EcoRI cutting DNA at its recognition sequence

Different restriction enzymes have different recognition sequences.

This makes it possible to create a wide variety of different gene fragments.

Restriction enzyme animation

Palindrome: word that is the same forward and backwords

Examples:racecardadmom

5'- G A A T T C -3‘3'- C T T A A G -5'

DNA Cut by a Restriction Enzyme Can be Joined Together in New Ways by Ligase

These are recombinant DNA and they often are made of DNA from different organisms.

Plasmids are Used to Replicate a Recombinant DNA

Plasmids are small circles of DNA found in bacteria.

Plasmids replicate independently of the bacterial chromosome.

Replication often produces 50-100 copies of a recombinant plasmid in each cell.

Pieces of foreign DNA can be added within a plasmid to create a recombinant plasmid.

Harnessing the Power of Recombinant DNA Technology – Human Insulin Production by Bacteria

Human Insulin Production by Bacteria

6) join the plasmid and human fragment

and cut with a restriction enzyme

Human Insulin Production by Bacteria

Mix the recombinant plasmid with bacteria.

Screening bacterial cells to learn which contain the human insulin gene is the hard part.

Route to the Production by Bacteria of Human Insulin

A fermentor used to grow recombinant bacteria.

This is the step when gene cloning takes place.

The single recombinant plasmid replicates within a cell.

Then the single cell with many recombinant plasmids produces trillions of like cells with recombinant plasmid – and the human insulin gene.

One cell with the recombinant plasmid

Route to the Production by Bacteria of Human Insulin

The final steps are to collect the bacteria, break open the cells, and purify the insulin protein expressed from the recombinant human insulin gene.

Route to the Production by Bacteria of Human Insulin

Overview of gene cloning. Cloning animati

on

Transgenics

Transgenic organism: organism genetically engineered by inserting a gene from another organism

Transgenic animals, plants, bacteriaresearch, medical, and agricultural purposes

Transgenic Bacteria

Insulin, growth hormones, and substances that dissolve blood clots

Transgenic bacteria slow formation of ice crystals on crops to prevent from crop damage, clean up oil spills, and decompose garbage

Transgenic Plants

Genetically engineered to have more resistance to insect or viral pests

Herbicide and insecticide resistant soybeans, corn, cotton and canola

Peanuts and soybeans that do not cause allergic reactions

Rice plants with increased iron and vitamins to decrease malnutrition

Transgenic Animals

Transgenic livestock produced to improve food supply and human health

Transgenic goats engineered to secrete a protein called antithrombin III which prevents human blood from forming clots during surgery

Pharming

These goats contain the human gene for a clot-dissolving protein that is produced in their milk.

Pharming is the production of pharmaceuticals in animals engineered to contain a foreign, drug-producing gene.

ProteinProtein AnimalAnimal UseUseAntithrombin IIIAntithrombin III GoatGoat Reduce amount of Reduce amount of

blood needed in blood needed in some surgeriessome surgeries

Factor VIII, Factor Factor VIII, Factor IXIX

Goat, Pig, SheepGoat, Pig, Sheep Treatment of Treatment of HemophiliaHemophilia

CFTRCFTR SheepSheep Treatment of cystic Treatment of cystic fibrosisfibrosis

LactoferrinLactoferrin CowCow Natural antibiotic Natural antibiotic and used in and used in coronary surgerycoronary surgery

Alpha-1-antitrypsinAlpha-1-antitrypsin SheepSheep Treatment of cystic Treatment of cystic fibrosis and fibrosis and emphysemaemphysema

LysostaphinLysostaphin CowCow An anti-bacteria An anti-bacteria compound that compound that prevents mastitis in prevents mastitis in cowscows

Spider Silk ProteinSpider Silk Protein GoatGoat Production of ultra-Production of ultra-strong, lightweight strong, lightweight medical industiral medical industiral materialsmaterials

The Guiness Book of Animal Records 1995. "Spider silk is the strongest of all natural and man-made fibres.... It is even stronger than steel: the dragline of a European garden spider (Araneus diadematus), for example, can support a weight of 0.5 g (0.002 oz) without snapping, whereas a steel strand of similar thickness will snap under the strain of just 0.25 g (0.01 oz)."

"Spider silk is extremely strong -- it is about five times stronger than steel and twice as strong as Kevlar of the same weight. Spider silk also has the ability to stretch about 30-percent longer than its original length without breaking, which makes it very resilient."

The Stem Cell Concept

A stem cell is an undifferentiated, dividing cell that gives rise to a daughter cell like itself and a daughter cell that becomes a specialized cell type.

The Promise and Possible Perils of Stem Cells

Stem Cells are Found in the Adult, but the Most Promising Types of Stem Cells for Therapy are Embryonic Stem Cells

The Inner Cell Mass is the Source of Embryonic Stem Cells

The embryo is destroyed by separating it into individual cells for the collection of ICM cells.

Some Thorny Ethical Questions

Is it ethical to harvest embryonic stem cells from the “extra” embryos created during in vitro fertilization?

Are these masses of cells a human?

DNA, the Law, and Many Other Applications – The Technology of DNA Fingerprinting

A DNA fingerprint used in a murder case.

What are we looking at? How was it produced?

The defendant stated that the blood on his clothing was his.

DNA Fingerprinting Basics

Different individuals carry different alleles.

Most alleles useful for DNA fingerprinting differ on the basis of the number of repetitive DNA sequences they contain.

DNA Fingerprinting BasicsIf DNA is cut with a restriction enzyme that recognizes sites on either side of the region that varies, DNA fragments of different sizes will be produced.

DNA samples treated with ethidium bromide are inserted into wells in a piece of agar (gel)

When a charge is applied, DNA which is negative will travel to the positive end of the gel

Smaller pieces will travel the furthest

Bands are visualized under UV light

A Site With Three Alleles Useful for DNA Fingerprinting

DNA fragments of different size will be produced by a restriction enzyme that cuts at the points shown by the arrows.

The DNA Fragments Are Separated on the Basis of Size

The technique is called gel electrophoresis.

The pattern of DNA bands is compared between each sample loaded on the gel.

Gel electrophoresis animation

Possible Patterns for a Single “Gene” With Three Alleles

In a standard DNA fingerprint, about a dozen sites are analyzed, with each site having many possible alleles.

A DNA Fingerprint

When many genes are analyzed, each with many different alleles, the chance that two patterns match by coincidence is vanishingly small.

DNA detective animation

HGP fingerprinting page

DNA and the Law

SLT 3/8/05

Some applications of DNA fingerprinting in the justice system.

Restriction Enzymes and Gel Electrophoresis

http://arbl.cvmbs.colostate.edu/hbooks/genetics/biotech/gels/virgel.html

Biotechnology Australia site - Games

Genetically Modified Foods

Many of our crops in the US are genetically modified.

Should they be?

GM Crops are Here Today

Source: Pew Initiative on Food and Biotechnology, August 2004.

Methods for Plant Genetic Engineering are Well-Developed and Similar to Those for Animals

1. Restriction enzyme cut plasmid2. Insert gene of interest3. Introduce to plant cells

Golden Rice is Modified to be Provide a Dietary Source of Vitamin A

Worldwide, 7% of children suffer vitamin A deficiency, many of them living in regions in which rice is a staple of the diet.

Golden rice (yellow) with standard rice (white).

Genetically Modified Crops

Genetically Modified Cotton (contains a bacterial gene for pest resistance)

Standard Cotton

GMOs, Especially Outside the US, Are a Divisive Issue

Protesters at the 2000 Montreal World Trade Summit

European sentiment

Current Concerns by Scientists Focus on Environmental, Not Health, Effects of GM Crops

The jury’s still out on the magnitude of GM crop’s ecological impact, but the question is debated seriously.

Current Concerns by Scientists Focus on Environmental, Not Health, Effects of GM Crops