Selective Breeding Have you ever seen a dog show on tv? How many different types of dogs were there?!
Selective Breeding We know all the dogs are the same species o So how did we end up with so many different breeds?! Selective Breeding – allowing only animals with desired characteristics to produce the next generation
Selective Breeding People use selective breeding to pass desired traits on to the next generation
Hybridization Hybridization – crossing dissimilar individuals to bring together the best of both organisms o The offspring are usually hardier o May include a fast growth rate with a resistance to a particular disease
Inbreeding When it comes to dogs and cats, we found particular traits we desired most We continued to breed these animals to produce more with similar traits Inbreeding – continued breeding of individuals with similar characteristics
Variation Variation exists in nature and is the key to the survival of a group of organisms o Imagine…everyone in this room was severely allergic to bee stings o Now, we drop a bee’s next right in the middle of the room o What would happen?!
Variation The bee allergy was an extreme example but you get the point Populations need variation! Breeders can increase the genetic variation in a population by inducing mutations, which are the ultimate source of genetic variation
Variation in Bacteria Bacteria reproduce very quickly! This allows bacteria to evolve rapidly Scientists have created useful “mutant” bacteria to do many jobs!
New Plants Scientists can use drugs that prevent chromosome separation during meiosis Polyploidy – when a cell has many sets of chromosomes o Animals usually die of this condition but plants can survive o Often creates larger and strong plant species
Manipulating DNA Genetic Engineering – making changes to DNA sequence Scientists can remove DNA from a cell, make copies and alter the sequence to what they wish!
Manipulating DNA In order to make copies of DNA scientists use a technique called polymerase chain reaction PCR – technique used to copy DNA
Manipulating DNA First the DNA must be extracted o Cells are broken open, proteins are broken down and DNA is removed Then the DNA is cut using restriction enzymes, which cut DNA at specific sequences
Gel Electrophoresis Scientists must then separate the DNA to be analyzed Gel Electrophoresis – DNA fragments are placed in one end of a porous gel and an electric voltage is applied to the gel. Smaller particles move faster.
Gel Electrophoresis DNA is usually dyed with a fluorescent marker to make it more visible
How is this Useful!? Knowing the sequence of DNA allows scientists to do some pretty incredible things! o Study specific genes o Compare genes of other organisms o Helps researchers discover the functions of genes o Can help to prevent or cure diseases
Transformation Transformation – when a cell takes DNA from outside the cell and integrates it with its own DNA Very easy to do with bacteria o Bacteria readily accept plasmids, simple circular structures containing recombinant DNA
Transgenic Organisms Transgenic – containing genes from other organisms o Genetic engineering has improved biotechnology Transgenic tobacco plant Contains genes from a firefly! Transgenic tomatoes Ripening gene has been turned off so the tomatoes have a longer shelf life
Cloning A clone is a genetically identical organisms created from a single cell. In 1997, Ian Wilmut was the first scientist to clone a mammal o Dolly the sheep was the first mammal to be successfully cloned!
GMOs Genetically Modified Organism o Good or bad? o Safe? o How far should we take it?