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  There can be positive effects though! –Faster or stronger cells!

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.