Reading Essentials for Biology Glencoe (794133), страница 36
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Why do scientists want tofamous cloned animal was Dolly the sheep, cloned in 1997. Theclone animals?cloning process is not efficient, but scientists hope someday to use________________________it so that ranchers and farmers can clone the most productive,healthy animals to increase and improve the food supply.________________________Scientists developed a method of replicating DNA outside of________________________living organisms, called polymerase chain reaction (PCR). Thismethod uses heat to separate DNA strands from each other.
Anenzyme from a heat-loving bacterium is used to replicate theDNA when the correct nucleotides are added to a PCR machine.The PCR machine can make millions of copies of DNA in a day.Scientists analyze bacterial, plant, animal, and human DNA.Scientists use this type of DNA analysis in crime investigations andin the diagnosis of disease. Scientists also use PCR to provide pureDNA that is used to determine the correct sequence of DNAbases. This information helps scientists identify mutations.4. Which three areas willmost likely benefit fromDNA technology?________________________________________________________________________146Chapter 13Applications of DNA TechnologyHow can humans benefit from DNA technology? Three mainareas seem to offer the greatest promise: industry, medicine, andagriculture.
For example, scientists have changed the E. coli bacteria to produce the expensive blue dye used to color denim bluejeans. Scientists are also trying to develop corn that contains asmuch protein as beef.In medicine, recombinant DNA is used to produce insulin andthe human growth hormone. The human gene responsible forclotting blood has been inserted into sheep chromosomes. TheREADING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Foreign DNA(gene for humanCleavage sites growth hormone)NameDateClassSection13.2Recombinant DNA Technology, continuedsheep produce the clotting protein, which is then used for patientswith hemophilia, a disease in which blood cannot clot quickly.Researchers are discovering ways to increase the amount ofvitamins in certain crops.
That will help provide better nutrition.Some plants have already been developed that produce toxins tomake them resistant to insects. That will limit the use of dangerous pesticides.◗ After You ReadMini Glossaryclone: genetically identical copy of an organismor genegenetic engineering: method of cutting DNAfrom one organism and inserting theDNA fragment into a host organism of thesame or different speciesplasmid: small ring of DNA found in a bacterialcell that is used as a biological vectorrestriction enzyme: DNA-cutting enzyme thatcan cut both strands of a DNA molecule at aspecific nucleotide sequencetransgenic organism: organism that containsrecombinant DNA from a different speciesvector: means by which DNA from anotherspecies can be carried into the host cell; maybe biological or mechanicalCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.recombinant (ree KAHM buh nunt) DNA:DNA made by recombining fragmentsof DNA from different sources1.
Read the terms and their definitions in the Mini Glossary above. Circle two terms that arerelated to one another. On the lines below, tell how these terms are related.________________________________________________________________________________________________________________________________________________________________________2.
In the boxes below, list the steps for producing a transgenic organism.Recombinant DNA Process for Producing a Transgenic OrganismStep 1Step 2Step 3Visit the Glencoe Science Web site at science.glencoe.com to findyour biology book and learn more about recombinant DNA technology.READING ESSENTIALSChapter 13147NameDateClassSection13.3 The Human GenomeSC.H.3.4.3 The student knows that scientists can bring information, insights, and analytical skills to matters of publicconcern and help people understand the possible causes and effects of events.
Also covers SC.F.2.4.2, SC.H.3.4.5, SC.H.3.4.6◗ Before You ReadThis section discusses the effort to identify and map all the human genes. When the project is finished,it will be an incredible accomplishment. On the lines below, give an example of another importantscientific achievement that you know about. Describe how the world might be different today if thatachievement were never made.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnIdentify MainIdeas As you read this section, stop after every fewparagraphs and put what youhave just read into your ownwords.
Then highlight themain idea in each paragraph.1. What is the HumanGenome Project?________________________________________________________________________148Chapter 13The Human Genome Project is an international effort tocompletely map and sequence the human genome. The humangenome is the approximately 35 000 to 40 000 genes on the 46human chromosomes. Sequencing means putting each of thesegenes in the right order. The project began in 1990.
Today, thousands of genes have been mapped to particular chromosomes.Half of the genome has been sequenced. But scientists still do notknow the exact location of all the genes on the chromosomes.The genetic map that shows the relative locations of genes on achromosome is called a linkage map. Imagine a map of your statethat shows cities as being north, south, east, or west of each other,but does not show the exact location of each city. That is how alinkage map works.
It shows relative location, not exact location.Originally, the information used to assign genes to particularchromosomes came from linkage data of human pedigrees.Remember that in meiosis, genes sometimes cross over onto different chromosomes. Scientists know that genes that are fartherapart cross over more often than genes that are close together.That information helps scientists create a linkage map. But mapping by linkage data is not efficient because scientists had to waitfor individual humans to reproduce and mature in order to identify which genes were passed on.Now, a faster more efficient way to map genes is available.Using polymerase chain reaction (PCR), millions of copies ofDNA fragments are cloned in a day.
Since scientists know theREADING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Mapping and Sequencing the Human GenomeNameDateClassSection13.3The Human Genome, continuedlocation of some genes and some segments of DNA, they are usedas genetic markers. Because DNA segments that are near eachother on a chromosome are often inherited together, markers areused to track the inheritance pattern of a gene that has not yetbeen identified.Genes are sequenced by cutting DNA into fragments usingrestriction enzymes. The fragments are cloned, then put in theright order. The order is determined by overlapping matchingsequences.
Machines can perform this work, increasing the speedof map development.Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Applications of the Human Genome ProjectHow will these chromosome maps be used? Doctors will beable to diagnose genetic disorders even in unborn babies.
Genetherapies might be developed to correct genetic disorders. Lawenforcement workers will be able to link suspects to evidence leftat crime scenes.Diagnosing genetic disorders has been an important benefit ofthe Human Genome Project. A diagnosis can be made beforebirth. Doctors take cells from the fluid surrounding the fetus andanalyze the DNA. They can determine if the fetus will develop agenetic disorder. Now, thanks to DNA technology, doctors canuse gene therapy to help individuals with genetic disorders. Genetherapy is the insertion of normal genes into human cells tocorrect genetic disorders.
Doctors are conducting experimentsinvolving gene therapy for cystic fibrosis, sickle-cell anemia, andhemophilia. Research is also going on to use gene therapy on cancer, heart disease, and AIDS. It is hoped that gene therapies willbe developed to treat many different disorders.DNA technology is also helping law-enforcement workers solvecrimes using DNA fingerprinting. All it takes is a small sample ofhair, skin, blood, or other body tissue found at a crime scene. Thissample’s DNA is then compared with a DNA sample from a suspect. If the DNA samples match, the suspect most likely is guilty.DNA fingerprinting works because no two individuals (exceptidentical twins) have the same DNA sequences, and because allcells of an individual (except gametes) have the same DNA.Geneticists are using polymerase chain reaction (PCR) to cloneDNA from mummies to better understand ancient life. The DNAfrom fossils has been studied to compare extinct species with living species, or even two extinct species with each other.
The usesof DNA technology are unlimited.READING ESSENTIALS2. What is gene therapy?________________________________________________________________________3. Why does DNA fingerprinting work?________________________________________________________________________Chapter 13149NameDateClassSection13.3The Human Genome, continued◗ After You ReadMini Glossarygene therapy: insertion of normal genes intohuman cells to correct genetic disordersmation on the treatment and cure ofgenetic disordershuman genome: map of the thousands of geneson 46 human chromosomes that whenmapped and sequenced, may provide infor-linkage map: genetic map that shows the relative locations of genes on a chromosome1.
Read the key terms and definitions in the Mini Glossary above. Write a sentence using atleast two of the terms correctly.________________________________________________________________________________________________________________________________________________________________________2. In the top row of boxes, write the ways that results from the Human Genome Project canbe used.
In the bottom row, give specific examples. One box from each row has been filledin for you.Applications of the Human Genome ProjectTreat patients withcystic fibrosis.3. Circle T or F to indicate whether each of the following sentences is true or false.TF1. Humans have more than 75 000 genes located on 48 chromosomes.TF2. A linkage map shows the exact location of a gene on a chromosome.TF3. Using polymerase chain reaction (PCR), millions of copies of DNA fragments can becloned in a day.TF4. Gene therapy is the insertion of abnormal genes into human cells to correct geneticdisorders.Visit the Glencoe Science Web site at science.glencoe.com to findyour biology book and learn more about the human genome.150Chapter 13READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Gene TherapyNameDateClassSection14.1 The Record of Life◗ Before You ReadSC.D.1.4.3 The student knows that changes in Earth’s climate, geological activity, and lifeforms may be traced and compared.
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