Biology: Mutations and DNA Technology
Proteins are the connection between the gene code DNA and how that gene is expressed.
MUTATIONS are changes in the base sequence of a gene. Mutations can happen when cells make
mistakes in copying their own DNA or be caused by radiation or chemicals in the environment.
GENE MUTATIONS:
Point Mutations are mutations that only involve one nucleotide. There are three kinds:
Substitutions- changes one base for another (G to T)
Deletions- one or more bases are lost/ deleted (base A is taken out)
Insertions- one or more bases are added (base C is added to the sequence)
Substitutions usually affect no more than a single amino acid, but deletions and insertions can have a more dramatic effect.
FRAME SHIFT MUTATIONS
Insertions or deletions that change multiple codons after that point
Frame shift mutations (insertions and deletions) change every amino in the protein that follows the shift.
Frame shifts can alter a protein so much it is unable to function
Mutations at the beginning of a gene damage more of the code.
Most mutations are neutral meaning they have little or no effect on gene function.
Mutations that cause defective proteins are usually harmful. Harmful mutations are associated with many genetic disorders and can cause cancer.
Mutations can also cause genetic variability can be beneficial. They can help an animal survive and reproduce. Mutations cause variation in population for natural selection to act upon.
If a mutation happens in a sex/ gamete cell, it could be passed on to offspring. If it happens in a body/ somatic cell, the mutation will not get passed on.
GENOME: the complete set of genetic material or DNA present in an organism
HUMAN GENOME PROJECT:an international, collaborative research program whose goal was the complete mapping and understanding of all the genes of human beings
DNA TECHNOLOGY ———
GEL ELECTROPHORESIS is a process in which DNA molecules are cut into pieces using restriction enzymes and then placed in a gel with an electric current and separated based on their size
DNA is negatively charged. Smaller pieces of DNA move quicker because they have less resistance in the gel. Larger fragments are closer to wells/ negatively charged side of the gel.
Gel electrophoresis can be used as a DNA fingerprinting tool due to the fact that every person will have a different band pattern of DNA fragments
Because an offspring of sexual reproduction will have half of each of its parents’ DNA, its gel electro bands should all match up to either the mom or the dad
GENETIC ENGINEERING refers to the direct manipulation of DNA to alter an organism's characteristics (phenotype) in a particular way
POLYMERASE CHAIN REACTION (PCR) is a method widely used to rapidly make millions to billions of copies (complete copies or partial copies) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) to a large enough amount to study in detail
A KARYOTYPE is a picture of an individual's complete set of chromosomes. The term refers to a laboratory- produced image of a person's chromosomes isolated from an individual cell and arranged in numerical order
GENE THERAPY involves transplanting normal functioning genes inside an individual's cells typically in an effort to treat a genetic disease. This is traditionally done by using a virus as a vector to transport the new genes but could also be done using stem cells
CRISPR is a genetic engineering technique in molecular biology by which the genomes (genetic information) of living organisms may be modified. By using the Cas9 enzyme, the cell's genome can be cut at a desired location, allowing existing genes to be removed and/or new ones added in vivo (in the organism itself).