Gene transfer & Geneti-cally modified organisms

JeHoon Oh

Definition of Gene

• Gene is the heritable factor that de-termines the phenotype and geno-type.

Definition of Genotype and Pheno-type

• Phenotype: characteristic of an or-ganism

• Genotype: It is the arrangement of al-leles in organisms.

State two examples of the currentuses of genetically modified crops

or animals.

• An example of genetically modified crop is the deactivation of the ripening gene in tomatos – (from page 245 biozones). The gene is deleted to control the ripen-ing.

• Another example is livestock improve-ment through use of transgenic animals. Transgenic sheep produces enhanced wool. – (from page 246 biozones).

Discuss the potential benefits andpossible harmful effects of one

example of genetic modification.

• Benefit: -Prevent the shortage of food -better quality of food with mineral and

vitamins-Longer duration of food ripening• Disadvantages:-Food can be unsafe to humans -Risk of having unknown effect to organ-

isms through gene transfer.

Outline three outcomes of thesequencing of the complete human genome.

• It would help identify much of 20,000 ~ 25,000 genes in human DNA

• It would improve store of information as data• Transfer could be done using technologies related to private sec-

tor(All this information referenced from http://

www.ornl.gov/sci/techresources/Human_Genome/home.shtml)-Also location of genes could be discovered-Evolutionary relationship can be more explainable(These two outcomes are referenced from http://i-biology.net/ibdpbio/04-genetics-and-geneticengineering/ge-

netic-engineering-and-biotechnology/)

When genes aretransferred between species, the amino acid sequence of polypeptides translated

from them is unchanged because the genetic code is universal.

All organisms use the same genetic code.

Thus, the gene should be transcribed and translated into same protein.

Outline a basic technique used forgene transfer involving plasmids,a host cell (bacterium, yeast orother cell), restriction enzymes

(endonucleases) and DNA ligase.

• The restriction enzymes (like CTAGG we learned in class from Ecori) are cut from genome to gain the desired gene.

• Plasmid is removed from Ecoli to get the same enzyme restriction.

• Same restriction enzyme can connect each other due to their same ends.

• Ligase is used like glue stick to join the stick ends, fixing the gene.

• This newly created gene is replaced into the host cell. (Human insulin is produced this way)

(Referenced from http://i-biology.net/ibdpbio/04-genetics-and-genetic-engineering/genetic-engineering-and-biotechnology/)