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Genetics & Biotechnology
MU Module 11
Applied Genetics
Section 1
Selective Breeding
Selective breeding occurs when we (humans) breed organisms with certain traits to produce offspring with desired traits.
Hybridization
A method of selective breeding
Crossing parents with different traits to produce offspring that are hybrids of the parents
The goal is to get certain traits in the hybrids that aren’t in either parent
Can take a long time (expensive)
Inbreeding
Closely related organisms with desired traits are bred to keep the desired traits and remove unwanted traits in the offspring
Not all undesired traits may be removed - sometimes harmful recessive traits show up in the offspring populations
Test Cross
Genotype = alleles (versions) of a gene present in the genome of the individual
When an individual's genotype is not known, a test cross can be used
Test cross = unknown individual is crossed with a homozygous recessive for the desired trait
DNA Technology
Section 2
Genetic Engineering
An alternative to selective breeding
Manipulate the DNA to select for traits in offspring
Adding DNA from another organism
DNA Tools
Goal: isolate the gene from the genome and manipulate the DNA (decrease/increase expression of that gene)
Restriction enzymes = enzymes that cut DNA into fragments by recognizing certain DNA sequences
Gel electrophoresis = separates DNA fragments by size
DNA fragments are loaded into a gel
An electrical current causes the negatively charged DNA to move through the gel
Smaller DNA fragments travel further/faster than larger fragments
Recombinant DNA Technology
Section 3
Recombinant DNA
Once the fragments of DNA (genes) have been cut out of the genome and separated, we can combine them with other fragments/genomes
Once combined, we can replicate the recombinant DNA for further study
Gene Cloning
A technique for replicating recombinant DNA
The DNA is recombined in a plasmid (withing a bacterium)
When the bacterium replicates, so does the plasmid (and the gene)
PCR
Polymerase Chain Reaction is another method of replicating the gene
PCR can make multiple copies of 1 gene from a single template
DNA Sequencing
A tool used to study the isolated gene
Once the sequence (A,G,T,Cs) of a gene is known, its function can be inferred by comparing it to known genes with similar sequences
Biotechnology
Scetion 4
Biotechnology is the application of genetic engineering to genetic problems
Organisms that contain DNA/genes from other organisms are called transgenic organisms
Animals are commonly used to study diseases
Plants are commonly used to study disease and pest resistance