4.4 Genetic engineering and biotechnology

DNA profiling

• Identify natural variations found in every person’s DNA

• Use variable number of tandem repeats (VNTR)– Short, repeated sequences of nucleotides e.g.

CACACA, ATTCGATTCG– Number of repeats are highly variable– No known function

4.4 How is DNA profiling useful?

• Forensic investigations– Collect samples such as

blood or semen to use as evidence for court case

• Investigate paternity– The bands on the child's

fragments are either found on the mother or the male1.

DNA profiling

1. Isolate DNA from biological materials from the crime scene (hair, blood, etc.) and possible suspects

DNA profiling

2. Polymerase chain reaction• Purpose: make copies of DNA• Two strands of DNA separate

(DNA denaturation due to high temperature)

• DNA polymerase from Thermus aquaticus (a bacteria that lives in hot springs)

• Synthesizes new DNA strand by using complementary strand as template

DNA fingerprinting process3. Cut the DNA into small

fragments via restriction enzymes

4. Gel electrophoresis• Method of separating mixture of

DNA• Mixture placed in well• Electric field is applied gel via

electrodes• Separate according to size and

charge (highly charged molecules move faster)

Will our gel look like this?

DNA profiling

5. Make single stranded DNA• Application of external stress:

strong compound (acid/base)

6. Add radioactive probe • DNA fragment containing

nucleotide bases complementary to gene of interest

• Hybridization

Try this!

DNA profiling – M. Andersonhttp://www.youtube.com/watch?v=DbR9xMXuK7c

Gel electrophoresis virtual labhttp://learn.genetics.utah.edu/content/labs/gel/

4.4 Genetic engineering and biotechnology

1. Blog: Describe the process of DNA profiling. 2. Feedback distributer: Fernanda

4.4.5 The Human Genome Project

• Begun formally in 1990 the international projects aims• Completed April 2003

Findings: 1. Number and loci of all genes in our genome (30,000). Fewer than expected =>

complex relationship between genes.

2. New proteins and functions discovered. Better drugs design using knowledge of protein structure

3. DNA comparisons can be made with other species. Closely related species share more similarities in the DNA sequence. Used to infer evolutionary history.

The Human Genome Project

• Genetic ‘report card’: contains individual genetic information – Who should have

access? – How should they use

it?

GMO & CloningFeedback distributer: Diego

If your topic is GMO, please sit in the middle.

Announcement: Learning Log

Gene transfer• Universality of genetic

code allows genes to be transferred from one organism to the other

• Genes are transferred between species, the amino acid sequence of polypetides translated from them is unchanged

Gene transfer• plasmids = vector = medium by

which genes of interest are transferred to host– small (2 - 30 genes) loops

of bacterial DNA

• a host cell (bacterium):– receives a gene of interest – via a vector replicates

repeatedly, passing on gene of interest to offspring

Gene transfer• restriction enzymes

produced naturally by bacteria as defense against viruses

– used to cut the desired section of the DNA– recognizes unique sequences of DNA in plasmid

and in gene of interest – Cuts complementary sticky ends in gene of

interest and plasmid– allow incorporation of gene of interest into

plasmids

• DNA ligase– creates covalent bonds– joining together gene of interest within

plasmid,– producing recombinant DNA

• GMO = genetically modified organism

Monsanto

• America’s BIG Agricultural biotechnology cooperation

• “Roundup”: Crops genetically designed to tolerate herbicide

• 80% of soybean, corn, cotton, sugar beets, and canola seeds grown in US are from Monsanto

Gene patenting

• Patent = Intellectual property right

• Right to prevent others from making, using selling patented product without permission

DiscussionBenefits Controversies

Questions:

Cloning

• Clone = group of genetically identical organisms or group of cells derived from single parent

Dolly – Word’s most famous sheep • Born 1996

• Three sheep: DNA donor, Egg cell donor, surrogate mother

• Electric shock causes two cell membranes to fuse and mitosis to trigger

• Embryo implanted into surrogate mother

• http://learn.genetics.utah.edu/content/tech/cloning/

Why clone?• Cloning for medical purposes

– Cloning animal models of disease: create multiple copies of transgenic organism with disease causing mutation in genes

– “Pharming” for drug production• Farm animals such as cows, sheep

and goats are genetically engineered to produce drugs or proteins

– Cloning stem cells for research

Why clone?• Retrieving endangered

or extinct species– Cloning dinosaurs? – Need well preserved DNA

• Reproducing a deceased pet– Cat cloning service in US

Why clone?• Cloning humans?

– Couples that can’t have child– Couples that have lost child

• Does everyone have right to have children, regardless of how they are created?

• Is human cloning playing with nature?