Gene mutations

• Mutations in codons can create different sequences of amino acids then intended, compromising its intended shape and functionality
• Mutation in the betaglobin in DNA codes hemoglobin that forms rigid structures that force the RBC to have a sickle shape. This gives the blood cell less space to bind to oxygen, can block blood streams, cause blockages and pain. Furthermore, they last for a shorter time, meaning their destruction can outpace production causing less oxygen to be carried in the blood stream
• Sickle cell anemia occurs when Adenine replaces Thymine in the DNA sequence and codes for Thymine instead of Adenine in the mRNA and amino acid sequence, replacing normal glutamic acid with valine
• Valine is non polar so it has a very rigid structure while glutamic acid is polar with a flexible and compressed structure
• Anemia that can lead to Jaundice (yellow eyes) fatigue, damage to eyes, heart, lungs, etc.
• Sickle cell anemia happens when 2 of the 4 polypeptides in the hemoglobin protein (the beta chains) have a base mutation causing them to be abnormal and inactive. The hemoglobin can only bind to 1/2 the usual amount of oxygen, causing anemia
• There are three types of mutations; Substation, Insertion and Deletion- all are rare and random
• Substitution; the switching of one base for another (sickle cell anemia)
• Insertion mutation: one or more bases are inserted between a code (extra- Huntington's disease)
• Deletion mutation: One or more bases are deleted from the DNA strand (CCR5 receptor protein = non-functional)
• The severity of mutations depend on where they occur- in a coding region (coding for proteins); they are of great effect
• Silence/Same sense mutation effect: A mutation that results in a same amino acid being encoded by the changed gene (no effect)
• Nonsense mutation effect: A base mutation that results in a stop codon being produced instead of the intended amino acid
• Mis-sense mutation effect: A base mutation that changes the amino acid that is inserted into the protein and can make it functional [unchanged] or unfunctional [changed] depending on the amino acid change and location (sickle cell anemia)
• Single nucleotide polymorphism: A single nucleotide that is different between individuals in a population.
• For sickle cell anemia, the beta chains are formed from a mutation is the base DNA sequence when Thymine is replaced by Adenine that is transcribed into an mRNA as Adenine instead of Thymine, and then is translated into valine instead of glutamic acid

  
• Gene mutation is the permanent, random and structural change in the base sequence of DNA
• Mutations can be POINT mutations (ex. base substitutions), or FRAMESHIFT mutations (deletions/insertions)
• Location of mutation affects the impact of it- it is more severe if mutation is present in coding regions over non-coding regions
• Frameshift mutations are a lot more severe than point mutations
• CCR5 is a receptor protein on the surface of white blood cells that HIV viruses can bind with to enter the cell and replicate throughout the body. Some people have mutations that prevent them from producing these receptors which means they are not able to contract the disease as HIV is locked out of their immune system
• Huntington's disease is a neurodegenerative disorder in which chromosome 4 codes for several too many CAG codons causing a frameshift insertion disease that leads to neuronal degeneration and neurological dysfunctions.
• Mutations can be caused by errors in DNA replication or repair, or due to mutagens like radiation or chemical substances that can also be carcinogens
• carcinogens - agent promoting the development of cancer
• Chemicals that can act as mutagens include nitrate and nitrate preservatives, barbecuing, benzoyl peroxide, UV radiation, asbestos, cadmium compounds, PVC, diesel exhaust, benzene, tobacco smoke, gamma rays, alpha particles
• Radiations that can act as mutagens include Gamma rays, X-rays, alpha particles from radioactive isotopes, short wave UV radiation
• "Single nucleotide polymorphism" or SNP is based on base substitutions that caused by degeneracy in genetic code that might or might not code for the same amino acid as intended. It is evolutionary and beneficial for increasing the diversity of the population
• Germ-like cells are responsible for reproductive cells (haploids) so any mutation in them is hereditary and present throughout the entire organism
• Somatic cells are body cells used to create specialized cells so any mutation in them cannot be inherited an only shows up in a specific area of the body
• A gene is a section of DNA with a base sequence about hundreds or thousands of bases long
• An allele is a variant of a gene differing in one or more baess from the original strand - consequences of mutation
• Mutations are changes to the base pair sequence of an organisms genetic code
• Spontaneous mutation: occurring without mutagens
• Physical mutation: Caused by radiation
• Chemical mutation: Caused by exposure to chemical mutants
• Alleles are different mutations of the same sequence in the same locus ex. OG: TCCGAT --> TCGAT / TCGGAT / TCCAGAT
• Biological mutations: caused by virus injection that mutate DNA
• Chemical, physical and biological mutations are not inheritable but spontaneous mutation is
• "Wildtype" - the original base sequence/non-mutated version of the gene that codes for the functional protein