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What percent of the produce in the grocery store is genetically modified ? |
Cloning: the creation of
an organism that is an exact
genetic copy of another. Every single bit of
DNA between two organisms is the same. Twins
are natural clones, they share the exact same DNA. How does one go about making
an exact genetic copy of an organism?
Somatic cell
nuclear transfer (SCNT) is one method of
cloning. In order to better understand this process visit this site and take
part in cloning your own mouse
.
Time line of genetics history
Transgenic breeding:
genetically-modified organisms
(GMO) For corn that is sweet, potatoes that are
non-toxic -- all crop plants, in fact -- you have genetic manipulation to thank.
And selective breeding is really just a primitive form of genetic manipulation.
When a breeder chooses a male plant and a female plant for breeding, what he or
she is really doing is choosing specific genes to combine from those two plants.
By hand-delivering pollen (sperm) from the male plant to the female flower
(which produces the egg), the breeder intervenes in the natural fertilization
process to ensure that traits from the two "best" plants get passed on to their
offspring. It's like an arranged marriage for plants.
But selective breeding is both imprecise and inefficient. Thousands of genes
combine at once, and the offspring plant may not receive the exact combination
of genes the breeder had intended. The breeder has no way of knowing whether the
desirable genes are in the sperm and egg; one can only guess, based on the
parent plants' appearance. Many offspring may need to be produced in order to
get one with the desirable trait. So genetic manipulation through selective
breeding is a slow process of trial and error.
Genetic engineering, however, is a targeted approach that allows scientists to
remove specific genes from one organism and insert them into another. The gene
recipient is called a genetically modified organism, or GMO (also called a
"transgenic"). This efficient technique is also remarkable because it allows
genes to be transferred between different species, for example, between a
flounder and a strawberry. Classical breeding could never achieve such a thing,
since it requires the parent organisms to be of the same species.
As genetic engineering techniques improve, more and more GMOs are being grown
and put on grocery store shelves. And while the GM food industry touts the
benefits of genetic modification, ranging from increased crop yields to enhanced
nutritional content of GM foods, the public is not convinced.
online activity
make your own crop, online activity
You decide and then vote online.
Only one-tenth of a single percent of DNA (about 3 million bases) differs from one person to the next. Scientists can use these variable regions to generate a DNA profile of an individual, using samples from blood, bone, hair, and other body tissues and products.
In criminal cases, this generally involves obtaining samples from crime-scene evidence and a suspect, extracting the DNA, and analyzing it for the presence of a set of specific DNA regions (markers).
Scientists find the markers in a DNA sample by designing small pieces of DNA (probes) that will each seek out and bind to a complementary DNA sequence in the sample. A series of probes bound to a DNA sample creates a distinctive pattern for an individual. Forensic scientists compare these DNA profiles to determine whether the suspect's sample matches the evidence sample. A marker by itself usually is not unique to an individual; if, however, two DNA samples are alike at four or five regions, odds are great that the samples are from the same person.
If the sample profiles don't match, the person did not contribute the DNA at the crime scene.
If the patterns match, the suspect may have contributed the evidence sample. While there is a chance that someone else has the same DNA profile for a particular probe set, the odds are exceedingly slim. The question is, How small do the odds have to be when conviction of the guilty or acquittal of the innocent lies in the balance? Many judges consider this a matter for a jury to take into consideration along with other evidence in the case. Experts point out that using DNA forensic technology is far superior to eyewitness accounts, where the odds for correct identification are about 50:50.
The more probes used in DNA analysis, the greater the odds for a unique pattern and against a coincidental match, but each additional probe adds greatly to the time and expense of testing. Four to six probes are recommended. Testing with several more probes will become routine, observed John Hicks (Alabama State Department of Forensic Services). He predicted that, DNA chip technology (in which thousands of short DNA sequences are embedded in a tiny chip) will enable much more rapid, inexpensive analysis using many more probes, and raising the odds against coincidental matches.
Assignment 1.5e - DNA and Traits
Scoring criteria
Part A
along with these
questions to dive into the world of cloning.View this short 
on cloning.
Part B
What's the controversy over GM foods? View this short
clip before you
begin part B.
Did you know that you have probably consumed food that is genetically modified.
How is it done? Visit this site from PBS
and actively participate in genetically engineering a "supercrop".
How do you feel about GM foods? Click on, "Should we grow them?" Read and answer each question. What is your vote? Explain why you voted this way.
Click on the "Engineer a crop". Read the information and then try the Selective breeding activity. Next perform the Transgenic Manipulation activity: Read carefully and list the steps used to make your plant. How can you test your tomato plant to see if you have succeeded?
Visit the guess, "what's coming for dinner?" section. Look over and review the items on the table. Pick two items from the table and summarize there involvement with GM foods.
Write a paragraph discussing at least 2 pros and 2 cons of GM foods.
Part C
Have you ever wondered how CSI
uses DNA to solve a crime, well now you will have a chance to do it on
your own. View thison
using DNA to solve crimes before you begin part C.
Visit this NOVA
site and begin solving the mystery. Begin by reading the introduction and
then start with part 1. List the steps for creating a DNA fingerprint and
give a brief summary of what happened for each step. Who is the
culprit in this crime?
- Analyze DNA "fingerprints" to solve a hypothetical paternity case
- Read the information at the link.
- Use this
- Answer the questions as they are on this word doc. (the questions have been modified from the web page version).
- Attach the completed word doc. to this assignment.
Research Links:
