BIOTECHNOLOGY The future is here!

MUTATIONS Mutation - changes in the DNA sequence that affect genetic information Types of mutations: Gene mutations - changes within a single gene Chromosomal mutations - changes within a whole chromosome (affects multiple genes)

Gene Mutations Point Mutation - a change in a single nucleotide (example: changing an A to a C) Frame-shift Mutation - an insertion or deletion of a nucleotide that causes a different reading of codons from the point of the change to the end of the gene

Point Mutations Normal AAT TAA TAG GAT TTT AAA Mutation AAT TAG TAG GAT TTT AAA The G was used instead of an A.

Frame-Shift Mutations Usually occurs as a result of an insertion or deletion Normal TAC GCA TGG ATT Insertion TAT CGC ATG GAT T T was inserted after the A.

Example using words: THE FAT CAT ATE THE RAT TEF ATC ATA TET HER AT Just like this mutated sentence does not make sense, frameshift mutations make nonsense proteins that cannot do their jobs correctly. DELETION of H

Chromosomal Mutations Deletion – when part or all of a chromosome is lost Duplication – when part of a chromosome is mistakenly repeated Inversion – when part of a chromosome becomes oriented in reverse of its normal direction Translocation – when one part of a chromosome breaks off and attaches to another nonhomologous (not the partner) chromosome

Chromosomal Mutations Deletion Duplication Inversion Translocation

When do mutations occur? During DNA replication, mistakes can be made when DNA polymerase adds complementary nucleotides. If this mutation or mistake happens very early on in a baby’s development, the mutation can affect the entire baby. The rest of the cells will have that same mutation. Remember, we all start off as one cell that must make many news cells through mitosis. Every time your cells divide, DNA has to copy itself and mistakes can be made.

If a one of your skin cells divides right now and a mutation occurs, this is probably not a problem. However, if the mutation causes certain genes to change, the new, mutated skin cell can become a cancer cell.

Cause of mutations Mutagen – any agent that causes DNA to mutate UV light Radiation Smoking Many different chemicals

Mutations gone wide Cats

Gene Regulation Only some of your genes are being expressed (used to make protein) at any given time. Your body needs mechanisms to “turn on” or “turn off” genes. Chemicals can act as blocks or starters. Some cancers are caused by genes being turned on that should not have been! For example, these genes can be turned on by smoking, which mutates DNA.

Types of Genetic Disorders Autosomal Dominant gene Example: Huntington’s Disease Autosomal Recessive gene Examples: Tay Sachs, Sickle Cell Anemia, and Albinism Sex-linked Genes (usually recessive) Examples: Hemophilia and color-blindness Chromosomal – entire chromosome or large areas of a chromosome is affected Random mutations Example: Progeria

Genetic Engineering Manipulating DNA

Working with DNA DNA Extraction Cells are chemically opened and the DNA is pulled out. Cutting DNA DNA strands from most organisms are much too large to be analyzed all at once. Somehow we must cut the DNA into smaller fragments.

Special enzymes are used to cut the DNA in specific places. These special enzymes are called restriction enzymes. These restriction enzymes cut the DNA molecule at specific sequences of nucleotides.

Recognition sequences

How do we separate the DNA fragments? ELECTROPHORESIS

Electrophor-what?!? Electrophoresis is a technique that separates DNA fragments (using electricity) in a jello-like slab based on the size of the fragments. Smaller fragments are able to travel longer distances more quickly. DNA has a negative charge so the fragments will flow toward the positive electrode (opposites attract).

DNA plus restriction enzyme Mixture of DNA fragments Gel Power source

If you were to compare two samples of the same DNA using the same restriction enzymes, the banding pattern would be the same. Different people make different banding patterns.

And why would we do this? DNA Fingerprinting Paternity Tests Children have a banding that is a combination of their mom’s and dad’s banding. Crime solving Identify the person who committed a crime (no two people have the same DNA) Medical diagnosis Determine if you have the gene that causes a disease or disorder.

Transgenic organisms Transgenic organisms contain genes from other organisms. Genes from one organism can be inserted into another organism.

Transgenic Bacteria Used to make: Insulin Human Growth Hormone Clotting Factors

Transgenic Animals Used to study genes and improve the food supply Mice with human-like immune systems. Livestock with extra copies of growth hormone genes. Sheep and pigs that produce human proteins in their milk.

Transgenic Plants Used for food supply and medical supplies Soy and corn Rice with additional Vitamin A Plants that produce blood proteins

Cloning Producing genetically identical organisms from one original cell. We have successfully cloned pigs, cows, mice, sheep, and monkeys. The first animal cloned was a sheep named Dolly in 1997.

A donor cell is taken from a sheep’s udder. Donor Nucleus These two cells are fused using an electric shock. Fused Cell The fused cell begins dividing normally. Embryo The embryo is placed in the uterus of a foster mother. Foster Mother The embryo develops normally into a lamb—Dolly Cloned Lamb Egg Cell An egg cell is taken from an adult female sheep. The nucleus of the egg cell is removed.