1 Genetics and Biotechnology Chapter 13 Selective breeding is used to produce organisms with desired traits. I. Applied Genetics A. Selective Breeding 1. Definedthe process by which desired traits of certain plants and animals are selected and passed on to their future generations. a. Ex. Breeding great tasting apple 3. Hybridization a. remindercrossing organisms with different forms of a trait to produce offspring with specific traits are hybrids. ex. Animal breeders, gardeners, scientist, etc. select traits that will give the organism a competitive edge. ex. Plant with disease resistance crossed with fast growing plant c. time consuming d. ex. Rice breeders took 30 yrs to hybridize rice. It can adapt to locations and more nutritious a. Finding a desired traitinbreed to make sure it is becomes a pure trait Ex. Clydesdale horses c. Disadvantage to inbreeding increases the chances of homozygous recessive traits to show up. B. 1. Definedbreeding an organism with an unknown genotype with a homo. recessive. a. If the unknown parent is homo dominant, all offspring will have the trait. If the unknown parent is heterozygous, the offspring will have another trait pop up. The phenotype ratio will be 1:1 White grapefruits are dominant while red is recessive. Wwhite, wred White = WW or Ww Red = ww only Breeder wants only white grapefruits.
2 Before he chooses a plant to cross, he/she wants to know if it a pure white grapefruit with WW and not a Ww. Breeder performs a test cross with a red (ww) grapefruit. WW x ww Ww x ww II. Researchers use genetic engineering to manipulate DNA A. B. 1. DefinedManipulating the DNA of one organism in order to insert the DNA of another organism. a. ex. Extract DNA that causes light from lightning bug to a plant. c. Transgenic organisms a. agriculture c. studying the development of a certain disease d. selecting traits that might be beneficial to humans. 3. What risks are associated with genetically engineered products? a. loss of native organisms 1. Intro a. Genomethe total DNA presen in the nucleus of each cell. humans have MILLIONS of nucleotides in their genome scientist must be able to isolate only the part of the DNA they are studying. Restriction enzymes Gel electrophoresis a. Definedproteins which recognize and bind to specific DNA sequences and cleave (cut) the DNA within that sequence because they constantly fight against viruses entering their DNA
3 c. scientists have isolated hundreds of these restrictive enzymes for use in DNA research. d. cut specific genes from DNA 3. EcoRI a. restrictive enzyme Unique in that it has sticky ends sticky ends lets them bind to other DNA and hook together. c. Other restrictive enzymes which are not sticky (blunt) then the fragments with 2 blunt ends can hook together. a. Definedthe ability to separate DNA fragments by using an electric current. DNA separates according to density and charge. Positive and negative ends in the gel. c. C. Recombinant DNA Technology 1. a. recombinant DNA (rdna) two DNA s from different sources are combined. A large amount of rdna is needed for research. One must make the rdna quickly and accurately. Scientists use bacteria as factories to make any kind of DNA segment needed to study. c.how do we make bacteria factories for us? Bacteria have a circular DNA and bits of DNA fragments called plasmids. Biotechnology companies sell plasmids that allow researchers to create rdna with special properties. For example, genes that glow, tags, etc. How do you get the part of the DNA into the bacterial DNA? (viruses or plasmids can be used as vectors to infect the bacteria with the wanted gene to be studied) DNA ligase enzyme pinches together the wanted gene into the circular DNA of the bacteria. The bacterial DNA now has been infected (by way of the vector) with the new gene and has Bacterial DNA that has been changed a bit with the new piece of DNA. Now The bacteria now has new instructions to pump (make/synthesize) NEW product.such as insulin etc.
4 D. 3. a. definedmaking an exact copy of a gene. using bacteria as factories to keep cloning the gene. a. Most DNA sequencing unknown in most organisms. Knowing the DNA sequence gives valuable information concerning the function of the organism. comparing of genes with similar sequences to identify mutations errors in the DNA sequence. a. Function Makes copies of specific regions of sequenced DNA Used to copy DNA for any scientific investigation, including forensic analysis and medical testing. c. PCR can detect a single DNA molecule in a sample. Very powerful tool. 1. Definedthe use of genetic engineering to find solutions to problems. a. when an organism has its own DNA and a bit from another organism. ex. Glowing Tobacco Plants DNA from firefly 3. Transgenic animals Cows which produce more milk. Goats make a protein in their milk to prevent clotting during surgery Chickens/Turkey that is resistant to diseases Future~making organs for organ transplants? a. Genetically engineered to be more resistant to insect or viral pests. (7million farmers in 18 countries) soybean cotton Developing peanuts and soybeans that do not cause allergic reactions. c. Rice with more iron and vitamins for third world countries. d. Variety of plants resistant to extreme weather conditions. e. working on banana s that may produce vaccines and plants that produce biodegradable plastics! 5. a. Used to produce
5 growth hormones blood clot blaster Used to slow the formation of ice crystals on crops to protect them from frost c. d. Decompose garbage III. Genome contain ALL of the information needed for an organism to grow and survive. (readable cookbook of DNA) A. 1. International project finished in 2003 G a. Definedcomplete genetic information in a cell. Human genome = 3 billion nucleotides! c. Human genomeif fused together as font size from text, it would extend from California to South America d. studied the genomes of smaller organisms to help handle larger organisms (mice, fruit fly, bacteria) 3. a. use just 2% of the nucleotides to make proteins for the body! Same in all humans (ex. Heart location etc.) 98% are noncoding sequences! UNIQUE to each person a. Noncoding sequences different in every individual c. People can be identified using the genetic information contained in blood, hair, semen, or skin. B. 1. Definedfield of study which involves creating and maintaining databases of biological information C. DNA Microarrays 1. Microscope slides or silicon chips with known DNA fragments Researchers can dye areas of study on a DNA and study them simultaneously P. 377 D. 1. Sections of DNA sequences may be altered by a single nucleotide in the genome. These are called single nucleotide polymorphisms. a. regions of linked variations identifying groups of SNP s in a specific location on a DNA
6 3. a. The study of how genetic inheritance affects the body s response to drugs. Helps to accurately dose drugs for an individual. c will allow for increase of safety, speed of recovery and reducing side effects. a. Defined a technique aimed at correcting mutated genes that cause human diseases Scientists insert a normal gene into a chromosome to replace a dysfunctional gene. rdna put in a virus virus infects the area DNA is corrected. trials for immune deficiency illnesses, diabetes, cancer, retinal disease, Parkinson s, and more.