Bellwork: What kinds of crimes can be solved using DNA evidence? Why?

Applications of Genetic Engineering Section 15.3

In today’s class we will… Looks at uses of genetic engineering for: Transgenic crops Transgenic animals Medicine and health Gene therapy Look at how our understanding of how genes are regulated has developed How DNA can be used to identify individuals To solve crimes Identify paternal relationships

How does genetic engineering benefit agriculture and industry? Life as we know it depends on living organisms What we eat What we wear Researchers have attempted to use genetic engineering to improve the products we get from plants and animals Overall goal is to produce better, less expensive and more nutritious food, and a less harmful manufacturing process

Genetically modified crops First introduced in 1996 In 2007 they made up 97 % of soybeans, 86 % of cotton and 80 % of corn in the US. Possibility of programming into plants a natural insecticide effect If plants have Bt gene to produce BT toxin, enzymes in insects convert Bt toxin to a lethal form, killing the insect Also possible to ’program’ into plants a natural herbicide resistance Increase farmers yield Can program resistance to viral infections Future possibilities include a resistance to rot and spoilage

Potential issues with GM crop usage In the USA, herbicide resistance has lead to an increased use of herbicides Herbicides are dangerous chemicals Potentially dangerous to humans Continued exposure could cause dangerous diseases such as cancer

GM crops usages in the united states

Genetically modified animals Transgenic animals are also becoming important to our food supply 30% of milk in US comes from cows that have been injected with hormones made by recombinant DNA techniques to increase milk production Transgenic salmon has been produced using growth hormones, which grows much faster than wild salmon Spider genes have been combined into cells of lactating goats Goat produces silk along with milk Sales of meat and milk from cloned animals has been legal in the US since 2008 You may have eaten cloned meat without realizing! Impossible to tell the difference (although cloned animals are normally only cloned for breeding stock)

How does recombinant DNA technology improve human health? Preventing Disease Food can be genetically modified to contain essential nutrients Example Golden Rice (See articles) Defficiancies in ProVitamin A can lead to infant bkindess Potential for transgenic plants and animals that produce human antibodies to fight disease Medical Research Transgenic animals can be used to simulate human disease where defective genes play a role Treating disease Using recombinant DNA in bacteria we can make proteins that were previously hard to make (Human growth hormone)

Gene therapy Can we simply replace a defective gene with a new improved version? New field of medicine call gene therapy is attempting to do this Possible due to advances in molecular biology and the human genome project Scientists genetically engineer viruses so that it can’t reproduce or cause harm DNA containing the modified gene is implanted into the virus Patient’s cells are infected with the virus In theory defective gene is replaced, but still experimental procedure

Genetic testing It is possible for potential parents to find out if they are carriers for genetic diseases such as cystic fibrosis Hundreds of genetic disorders can be identified Specific DNA sequences that detect the complementary base sequences are used to identify the gene causing alleles

Examining active genes Genes in the human body are not always active Explains how cells function normally, and what happens when cells don’t work properly Scientists use a DNA microarray technology to study hundreds or thousands of genes at once This is a glass slide or silicon chip that to which spots of single stranded DNA are tightly attached If you want to compare genes from cancer cell to genes from normal cells in the same tissue, mRNA is extracted from both cell types and copied into single stranded DNA with a fluorescent color. These cells compete for binding sites on the slab Slab is scanned to see whether cancer cells or normal cells produce more of a particular kind of mRNA – you can visually see which has bound more to the spot for a gene YouTube video DNA microarrays…..

How do we use DNA to identify individuals? Remember, every individual has a unique genome Except for identical twins This idea is the basis for DNA fingerprinting Sections of DNA that widely vary from one individual to another, bit have little or no function are analyzed Gaps between genes

How is the fingerprint produced?

Forensic Science DNA fingerprinting has been used since the 1980s Revolutionized Forensics Used to solve crimes, convict criminals, even overturn wrongful convictions DNA has overturned over 110 wrongfully convicted death row prisoners Also used to target ivory trade Investigators can identify which herd ivory came from on the basis of DNA

Establishing family relationships DNA fingerprinting makes it possible to identify alleles carried by the child that are not carried by mother Any others must come from the father They will be present in his DNA fingerprint It is 99.99 % effective Determining ancestry can be a bit hard, due to the genetic scrambling during Meiosis and sexual reproduction We do have some clues.. Y chromosome always passes father to son Mitchondrial DNA always passes mother to child

Summary Genetic engineering is a very useful aspect of Moelcular Biology Transgenic plants and animals can have numerous benefits to society Recombinant DNA can be used to create medicines Gene therapy is a new exciting field with a lot of potential for treating genetic diseases Our understanding of how genes are activated is ongoing using DNA microarrays Finally, DNA can be used to trace individuals Solving crimes Identifying paternity