Honors: Genetic Applications – Biotechnology- Ch. 13

Biotechnology = use or alteration of organisms, cells or biological molecules to achieve practical goals

Genetic engineering = modifying genetic material to:

- better understand inheritance: locate genes, find diseases

- improve treatment for disorders: cures, prevention

- improve plants/animals: modify foods

Who does this?

BioGen, Celera , Millennium, Pfizer, USA – NIH- 23 bil in 2002

Techniques

Genetic Recombination- use a circular bacteria DNA strand called a plasmid, and insert it into bacteria which makes it part of its own DNA = transformation (Griffith)

- detect DNA function by testing the bacteria, ex. Amp plates

Restriction enzymes - proteins from bacteria that cut at specific sequences of DNA and cut it, usually protect the bacteria from foreign DNA

- creates “sticky ends”, can insert new DNA

- use to break DNA into pieces, ex. EcoRI, BamIII

DNA hybridization – label a piece of known DNA with radioactivity (called a probe), mix in unknown DNA and look for places where they bond = southern blot

Gel electrophoresis - separating pieces of DNA based on their size.

- DNA is - charged. Put a - charge on it and it will move away.

- Place this in a matrix with pores (agarose), the smaller pieces will travel faster

- You can thus separate pieces of DNA or genes, find the size of them, remove them from the gel. Purify them to have the gene.

Northern – gels using mRNA

Westerns – gels using proteins

PCR - polymerase chain reaction - way of making huge amounts of DNA fromm 1 piece, p235

DNA sequencing - take a strand of DNA and cut it with eenzymes that cut at A, C, T, G and 1 by 1 get the sequence of the DNA

Applications

Cloning or Nuclear Transfer– p194-195

- Take a cell from specie A and remove the nucleus, place that into an enucleated egg cell from specie B

- use electricity to fuse them, culture, put back in the organism that the egg was from (B), baby is born with same nuclear DNA

- why? study development, make better animals

DNA fingerprinting - comparing the same pieces of DNA from people using restriction enzymes and gel electro.

- use RFLP's - repeats

- the sizes can be matched. Ex. OJ case, paternity, crimes: 1 in 57 billion (10x # people on earth) OJ was innocent

Transgenes - taking genes from one organism and putting it into another species

- has been done for ages with food, now more advanced

- ex. a gene in an insect produces a toxin; this gene is placed into corn, which is then produced by the corn. When produced it wards off predators, thus significantly increasing crops

- Also being done in animals. Ex. taking insulin gene and putting it in bacteria ex. glowing rabbit

Xenotransplant - transplant of an organ for 2 different species, ex. pig hearts

- problem is disease

Gene therapy - inserting the correct gene into cells to replace the damaged gene.

ex. in CF it was thought this would work. It hasn't but we have come a long way since then

- use of vectors to transport the gene

Human genome project - to sequence all the genes in the human species, big 1st step that is completed, the hard part is how to use this information.

- 3.2 billion base pairs, 30,000 + genes, 750 MB of info, 5,000 books

- Make drugs, gene therapy or replacement

- Venter and Collins ran most of the project

- Who owns? - Patents→ women who wanted to patent herself

- Use DNA probes to find similar genes in other organisms

- sequences of these are known : 77 known including several E. coli strains, TB, some strep strains, Salmonella, C. elegans, Drosophila,

- close – Paramecium, zebrafish, frog, mouse

Fertility – improvements have come because of biotechnology

- no more test tube babies

Ethics - all of these genetic issues bring up ethical questions.

-ex. Selective abortions, genetic screening for jobs, insurance etc.

http://www.ncbi.nlm.nih.gov/