DNA and Mutations

What is DNA? DNA (Deoxyribonucleic acid) is found in all living things. It is the carrier of genetic information

DNA affects how an organism looks, behaves, and how it’s body functions. You found some of those traits earlier in this unit!

Sections of DNA are called genes Many genes stacked together form our chromosomes You have 46 chromosomes, 23 from mom, 23 from dad.

Genes can come in multiple forms-usually dominant or recessive

The genes for blood type have 3 different versions (3 different alleles) – A, B, and o These genes tell the blood cell what type of protein to have on the cell membrane surface

The phenotype (physical appearance) is controlled by the genotype (genes) of the organism.

But what if there is a change to the genotype? A small change in the genes can cause a big change in the appearance and traits of the organism!

Objectives Define mutation Identify causes of mutations Describe effects of mutations

What is a Mutation? Any permanent change to DNA is called a mutation.

What is a mutation? The DNA can be changed in several ways

What is a mutation? A mutation can happen to a small section of DNA or to a chromosome

What causes a mutation? Mutations are a natural process that has been occurring for millions of years, changing DNA a little at a time.

What causes a mutation? Many times a mutation occurs naturally during mitosis. That mutated cell often doesn’t survive to divide again.

Other causes of mutations can be environmental – Radiation (x-rays/gamma rays), UV light, chemicals (cigarettes), or viruses (HPV) can cause mutations in the DNA Normal DNA and DNA being hit by x-rays and radiation

What are the effects of mutations? Are mutations bad? Can I get superpowers from a mutation?

What are the effects of mutations? Most of the time, there is NO effect! The cell may fix the mistake or destroy itself and the mutation does not get passed on.

What are the effects of mutations? Or the mutation may have occurred in a section of DNA that does not affect the organism’s genes.

Effects Sometimes the mutation can be harmful to the organism.

Harmful mutation in humans Sickle Cell- red blood cells cannot carry oxygen as well due to their shape.

Uncontrolled growth of a mutated cell can lead to cancerous tumors

Effects Sometimes the mutation can be helpful to the organism-which banana would you prefer?

Effects Watermelon anyone?

Effects Double muscled (Belgian Blue) cattle with myostatin mutations

Effects Some gardeners will purposely expose seeds to radiation to cause mutations in their plants

Blue eyes are a mutation

Even bacteria can benefit from having mutated DNA- they can avoid being killed by an antibiotic

Review and Summary Mutations are a change in DNA They occur naturally but can also be caused by environmental factors Most of the time, there is no effect to a mutation, but other times, the mutation can harmful or helpful to the organism.