DNA Mutations

What is a gene mutation? Often times, parts of DNA will have a base (or more) missing, added, or incorrect Can be caused by: errors in replication, transcription, cell division, or by external agents (like radiation)

What is a gene mutation? A mutation is any change in the Nucleic Acid (DNA/RNA) sequence. Any agent that can cause a mutation is a mutagen. Any mutagen that causes cancer is a carcinogen Any mutagen that causes birth defects is a teratogen

Mutagens Any agent that can cause a mutation These are caused by factors in the environment such as: Radiation (x-rays, UV, nuclear) Chemicals Extremely high temperatures Biological agents such as HPV

How common are mutations? Mutations occurs at a frequency of about 1 in every 1 billion base pairs Everybody has about 6 mutations in each cell in their body!

The most common types of mutations are : Point Mutations 1.Substitution 2.Insertion w/ frameshift 3.Deletion w/ frameshift Chromosomal Mutations 1.Deletion (a piece missing) 2.Duplication (a piece copied) 3.Inversion (a piece flipped) 4.Translocation (a piece moved to another location)

DNA (Gene) Mutation 1. Substitution – a different base is substituted for the original Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TGC - TTC What has happened in this mutation?

DNA (Gene) Mutation Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TGC - TTC *Adenine was accidentally replaced with thymine *What is this mutation called?

Substitution Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TGC - TTC What will happen to the amino acids?

Original DNA- ATC would code for : STOP Mutated DNA of TTC would code for: Lysine

DNA (Gene) Mutation 2. Insertion with Frameshift - produce extra copies of parts of a chromosome. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TAG – CAT - C What has happened in this mutation?

DNA (Gene) Mutations Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TAG – CAT - C *Adenine was inserted, causing the remaining DNA to shift to the right. *What is this mutation called?

Insertion with Frameshift Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TAG – CAT - C What will happen to the amino acids?

DNA (Gene) Mutation 3. Deletion - loss of all or part of a chromosome. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TCA- TC What has happened in this mutation?

DNA (Gene) Mutation Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TCA- TC *Guanine was removed, causing the remaining DNA to shift to the left *What is this mutation called?

Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TCA- TC Deletion w/ Frameshift What will happen to the amino acids?

What happens if you accidently skip an answer on a scantron sheet?

Substitution or Point Mutation THE DOG BIT THE CAR THE LOG BIT THE CAR THE DOG BIT THE CAT THE DOG HIT THE CAR THE HOG BIT THE CAR THE FOG BIT THE CAR

Insertion Mutation THE DOG BIT THE CAR THH EDO GBI TTH ECA R

Deletion Mutation THE DOG BIT THE CAR THE OGB ITT HEC AR

Gene mutations 4. Point mutations Change one nucleotide or just a few nucleotides in a gene Examples: sickle cell anemia & cystic fibrosis Cancer, color blindness 5. Frame-shift mutations The reading pattern is displaced and “shifts” into new positions Examples: duchenne Muscular Dystrophy

Frame shift mutations The cat and the rat ran far. The ca and the rat ran far. t

Chromosomal mutations 6. Inversion = reverse the direction of parts of a chromosome. 7. Translocation = occurs when part of one chromosome breaks off and attaches to another different chromosome.

Mutations: Changes in DNA Advantages: Abnormal, even lethal genes can be passed on to offspring Disadvantages: New, stronger genes can be passed on to offspring

Are they harmful? b. Silent mutations – changes the nucleotide sequence by has no effect on the synthesized protein c. Non-sense mutations – creates a protein that is not usable. HARMFUL

Construct the Chart: Cut out chromosomes to compete the chart on Chromosomal Mutations

Chromosomal Mutations