Genetics & Biotechnology

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

• A method of selective breeding

• 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

DNA Tools

• 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

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Biotechnology

Scetion 4

Biotechnology

• 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