DNA Mutations

Mutations Occur 1 of 2 ways 1. DNA damage from environmental agents such as UV light (sunshine) 2. Mistakes when copying DNA

DNA Damage from Environmental agents EXAMPLES Skin Cells with sun exposure Lung cells with cigarette smoke Radiation Cells have the ability to repair damages, but as an organism ages, DNA repair does not work as effectively; thus changes occur in the DNA

Original Strand of Nucleotide Bases

Damage from environmental agents

Mutation: modifying nucleotide base When DNA strands are separated and copied, the altered base will pair with an incorrect base and cause a MUTATION! Environmental factors

G now pairs with T, instead of forming a normal pair with ___.

Mutation: breaking phosphate backbone TRANSLOCATION Breaking the phosphate backbone of DNA within a gene creates a mutated form of the gene. Caused by environmental agents such as nuclear radiation which can break the bonds between oxygens and phosphate groups Answer: It is possible that the mutated gene will produce a protein that functions differently

What might happen if the phosphate backbone is broken?

Mistakes created during DNA duplication: Mutations occur when DNA polymerase makes a mistake. ODDS 1 in 100,000,000 bases DNA repair proteins fix many of these mistakes

What kind of mutations are there? Point mutation Frame-shift mutation Deletion Insertion Inversion DNA expression mutation

Point Mutations A simple change in one base of the gene sequence. Original: The fat cat ate the wee rat. Point mutation: The fat hat ate the wee rat. Changed the ‘c’ in cat to a ‘h’

Frame Shift Mutation One or more bases are inserted or deleted but keeps the original spacing. Original: The fat cat ate the wee rat. Frame Shift: The fat caa tet hew eer at. The ‘t’ from cat was removed, but kept the original letter spacing.

Deletion Mutations that occur when DNA is missing. Original: The fat cat ate the wee rat. Deletion: The fat ate the wee rat. Deletion of the word ‘cat’

Insertion Mutations that occur when extra DNA is added to the strand, insertions can also cause frame shift mutations. Original: The fat cat ate the wee rat. Insertion: The fat cat cat ate the wee rat. Extra ‘cat’ added to the sequence

Inversion An entire section of DNA is reversed. Original: The fat cat ate the wee rat. Inversion: The fat tar eew eht eta tac. cat ate the wee rat is inverted tar eew eht eta tac

American botanist Barbara McClintock won the Nobel Prize for discovering that corn genes were moving from one location to another in the chromosome. Jumping genes

Studies of prematurely old mice hint that DNA mutations underlie aging

Darwin’s Finches

Mutations can occur within a gene preventing the synthesis of the correct protein

“GFP Bunny” comprises the creation of a green fluorescent rabbit; the use of genetic engineering to transfer natural or synthetic genes to an organism to create unique living beings.

Mutations Can Be…… Harmful / Lethal Beneficial / Adaptive Neutral: most common / Variations

Genetic Variations within a Species