DNA TechnologyChapter 13Honors Biology

Genetically Modified Organisms•Modified genome of an organism

▫Takes DNA from multiple sources and combine them to form a new genome DNA from same species DNA from different species- Transgenic

organisms

Crops that

•Do NOT need fertilizer

•Disease resistant plants

•Insect resistance

•Herbicide resistant

•Salt-tolerant plants

Golden Rice• Insertion of

genes to produce a precursor of vitamin A (beta-carotene)

• Helps areas where there is a shortage of dietary vitamin A Golden

riceWhite rice

Dangers of GMO’s

•Unexpected allergies

•Introduction of new genes to a population▫SUPER

WEEDS•Creation of

invasive species

See the hornworm beginning to form at the leaves!

This hornworm eats and destroys the tomato plant!

Hornworms attack tomato and tobacco plants

DNA Fingerprints

•I. DNA Fingerprints pattern of bands made up of specific fragments from an individual’s DNA

•USED FOR:▫DETECTION OF A RELATIVE▫SIMILARITIES BETWEEN SPECIES

▫Forensics

Forensics- DNA fingerprinting

•VNTR- Variable number

tandem repeats

•Show variations in length

between individuals

•Can be compared with

DNA databases (CODIS)

What about twins?

•Dizygotic (fraternal twins) do not have the

same DNA

▫More like siblings that happen to be the

same age

•Monozygotic (identical twins)have identical

DNA

▫But not identical fingerprints!

How do you make DNA fingerprints?

•RFLP (restriction fragment length polymorphism) analysis▫1. extract DNA from specimen using

restriction enzymes▫2. separate fragments of DNA using

electrophoresis (separates DNA according to size and charge)

▫3. placed in wells made on gel and run electric current through gel

▫4. blotted onto filter paper/ photgraphic film.

Analysis▫negative fragments migrate to positive charged end of gel but not all at same rate

▫pores in gel allow smaller fragments to migrate faster separating fragments by size.

• Electrophoresis “electro” = electricity “phoros” = to carry across

• Determine the genetic differences and the

evolutionary relationship among species of

organisms

• Method that separates on basis of size, electric

charge and other physical properties

Can you tell who could be the father? Circle matching DNA bands

Are you related? Linkage analysis

•A mother, father, and their four “children”

Accuracy of DNA Fingerprints•DNA fingerprints are very accurate

•However, genetic tests can only absolutely disprove, not prove, relationship!

•Courts accept 99.5% accuracy as proof of alleged paternity

Evolutionary linkage- Common ancestor?

Polymerase Chain Reaction (PCR)

•Used when you only have a TINY piece of DNA

•PCR can be used to quickly make many copies of selected segments of the available DNA

•Use a PRIMER to initiate replication

•DNA doubles every 5 minutes

PCR is used for:•1. Forensics▫increased the amount of DNA evidence for testing

•2. Diagnosing genetic disorders

•3. Studying ancient fragments of DNA (tiny amounts)

Vaccines•Used to improve

immunity against certain diseases

•Present- Uses weakened or dead versions of the microorganism▫Risk of the body not

being able to handle the infection

▫Risk of dead organisms reviving

DNA Vaccines

•Future- DNA vaccines- using specific parts of DNA that code for antigens ▫No risk of infection

Avian flu- virus

Cloning

• Growing a population of genetically identical cells from a single cell.

• 1997 - Ian Wilmut with Dolly, the cloned sheep

• CLONE• 1. A cell, group of

cells, or organism from and genetically identical to a single ancestor.

• 2. An organism descended asexually from a single ancestor.

• CLONING• 1. To make multiple

identical copies of a DNA sequence.

• 2. To create or propagate an organism from a clone cell.

• 3. To produce a copy of.

Clone vs. Cloning

Uses• Cloning can be used to test for

genetic diseases

• Regenerate nerves or spinal cord

tissue

• Help in plastic surgery

• Clone organs for transplantation

• Grow skin grafts for burn victims

• Manufacture bone, fat, and

cartilage

Steps

1. Remove nucleus from egg cell

2. Fuse de-nucleated cell with a body

cell from another adult

3. Cells fuse to become 2N and then

divides

4. Implant embryo in reproductive

system of foster mother

Ethical Issues

What are the implications of cloning?How will cloning affect the medical field?

What will be the effect on the gene pool?

Is there potential for abuse?How should it be regulated?Would you consider cloning yourself?

Stem Cells

•Self renewing-regenerate•Multi-potency- can become many different

types of cells

•Uses▫Basic Knowledge of Human Development▫Models of Human Disease▫Transplantation-Cell Replacement ▫Drug Development ▫Organogenesis