MONSTROUS MUTATIONS!!!

What is a mutation?

• Mutations are changes in DNA!

• However, these simple changes or mistakes can cause big changes in phenotypes of organisms!

Mutations in reproductive cells…

• If a mutation happened during the creation of the reproductive cells… – There could be non-functioning cells – New traits might be produced – Proteins may not work correctly – Embryo may not survive – Faster or stronger cells!

 • There can be positive effects though!

Mutations in body cells…

• If mutation is caused by radiation and it is a non-reproductive cell, the mutation may not be passed on to the offspring.

• However, the mutation could cause problems for the individual.

• Damage to the gene could impair the function of the cell.

– Muscle cell may lose its ability to make the protein necessary for contraction – Skin cell may lose its elasticity.

Mutations in body cells…

• When the cells divide, the new cells will have the same mutation!

• Aging may be caused by a buildup of these mutated cells!

• Cancer is also caused by a mutation in the cell’s rate of division.

Point Mutations

• A point mutation changes a single base pair in the DNA sequence.

• What could this cause?

– Change in amino acid sequence – EX: THE DOG BIT THE CAT.

THE DOG BIT THE CAR.

This is a BIG difference!

• In general, point mutations are less harmful than other mutations because it only changes one base in the sequence.

Frameshift Mutations

• A frameshift mutation occurs when a single base is added or deleted from the DNA sequence.

• This is a problem because it shifts the reading of codons by one base and thus a totally different protein is produced!

Chromosomal Mutations

• Chromosomal mutations are changes at the chromosomal level.

• Some of these changes may be caused by: – Chromosome parts breaking off – Lost parts of chromosomes – Parts that rejoin incorrectly – Parts that rejoin backwards or even the wrong chromosome part

Effects of Chromosomal Mutations:

• Occurs most often in plants!

• Few chromosomal mutations are passed on to the next generation because the zygote usually dies.

• If the zygote lives and grows up, usually it is sterile and cannot produce offspring or pass on the mutated genes.

Causes of Mutations

• Some mutations just happen! Similar to a silly mistake on a math problem. These are called SPONTANEOUS mutations!

• Many mutations are caused by environmental factors, such as, radiation.

• MUTAGENS are agents that can cause errors in DNA. – EX: high energy radiation, chemicals, high temperatures.