3.5 Genetic Modification and Biotechnology

Formation + use of Bt crops in agriculture

Corn modified w/ a bacterial insecticide gene so that it produces insect toxins w/ its cells, protecting it from pest species.

Different ways natural clones can arise

Embryo splitting, fission + budding.

Determine the # and size of DNA fragments after being exposed to restriction enzymes (both linear and plasmid DNA).

In linear DNA from eukaryotes, # of fragments is 1 greater than the # of restriction cut sites. In circular DNA from prokaryotes # of fragments is = to # of restriction cut sites. Size of fragments is determined by subtracting bp # of cut site from total # of bp or finding difference btwn cut site bp.

Ex of cloning animal embryos via natural + artificial embryo splitting

In nature, embryo splitting results in identical twins. Artificially, can be performed in livestock embryos. Use a "squirt" of saline solution or a special micro-scale scalpel to split the embryo.

Impact of Bt corn on monarch butterflies

Leads to increased death of monarch butterflies.

Contrast sexual + asexual reproduction.

S: offspring show family resemblance but siblings vary b/c they inherit different combinations of genes from 2 parents. A: produced genetically identical offspring that inherits all their DNA from a single parent.

Analyze DNA profile to determine relatedness/forensic guilt

See diagram.

Process of reproductive cloning via somatic cell nuclear transfer

See diagram.

Source + use of pharmaceutical insulin prior to use of gene transfer tech

See diagram.

Describe the role of restriction enzymes in nature and in biotechnology applications.

They are found in bacteria who use enzymes to break viral DNA into useless fragments. In biotechnology, restriction enzymes cut DNA into smaller fragments.

Benefits of using gene transfer tech in production of pharmaceutical insulin

Today it is made from the human gene that codes for the insulin protein and is expressed + cloned in the bacterium, E. coli. Large quantities of E. coli are now grown in fermentation vats to make tons of human insulin available to the growing # of diabetic patients.

How universality of genetic code allows for gene transfer btwn species

A gene determines a particular trait by encoding for a specific polypeptide in a given organism. B/c genetic code is (almost) universal an organism can potentially express a new trait if the appropriate gene is introduced into its genome. Transfer of genes btwn species is gene modification + the new organism is a transgenic.

Define clone

A genetically identical organism.

Process of reproductive cloning via embryo splitting

A pluripotent embryo is separated into separate cells which can each develop into separate individuals.

Process of DNA profiling

A sample of DNA is obtained. PCR is used to produce more copies of the DNA. DNA cut into fragments by restriction enzymes. DNA fragments are separated by size via electrophoresis. Fragments separate into series of bands. Bands compared btwn different samples. If banding pattern is the same, then DNA is from the same source. Children will share bands w/ either 1 or both parents. Used for paternity tests, forensic analysis, genetic disease diagnosis + evolutionary analysis.

Potential environmental, health + agricultural benefits and risks of an example of genetically modified crop

Agricultural crops are commonly modified to improve yield, growth rates + nutritional value. Could increase evolution of resistance in certain pest populations, transferred genes could mutate + cause unexpected risks + could create super weeds.

2 ways risk of scientific research can be assessed

Ask Pasqualucci.

Production of Dolly the sheep using somatic cell nuclear transfer

Ask Pasqualucci.

Assess the risks + benefits of an ex of a genetically modified crop

B: Increased disease resistance, less use of chemical herbicides + increased nutritional content. R: Could be toxic to humans, non-target organisms affected by toxins and increased resistance to toxin evolves in pests.

Ex sources of DNA that can be used in DNA profiling

Blood, saliva, semen + tissue samples

Define cloning

The process of creating an organism genetically identical to its ancestor.

Function + purpose of DNA electrophoresis

Used to separate molecules according to their size. Result = series of bands each containing molecules of a particular size. Band pattern can be used to identify individuals for forensic purposes, paternity testing, to determine evolutionary relationship btwn species + to test for genes associated w/ a disease.

Describe a technique for genetic modification

mRNA which codes for insulin is extracted from a human pancreatic cell which produces insulin. DNA copies are then made from this mRNA by using enzyme reverse transcriptase + these DNA copies are then extra guanine nucleotides to end of gene to create sticky ends. @ same time a selected plasmid is cut using restriction enzymes which cut the DNA @ specific base sequences. Then extra cytosine nucleotides are added to create sticky ends. Once we have both plasmid + gene ready, these are mixed together. The 2 will link by complementary base pairing + then DNA ligase is used to make sugar phosphate bonds. Plasmids w/ human insulin gene can then be moxies w/ host cells such as bacterium. Bacterium will take in plasmid + start producing insulin which can then be collected + purified.