Human Genome

BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor

CHAPTER 12 DNA Technology and the Human Genome Modules 12.15 – 12.21 From PowerPoint® Lectures for Biology: Concepts & Connections Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

THE CHALLENGE OF THE HUMAN GENOME 12.13 Most of the human genome does not consist of genes • The 23 chromosomes in the haploid human genome contain about 3 billion nucleotide pairs – This DNA is believed to include about 35,000 genes and a huge amount of noncoding DNA

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• Much of the noncoding DNA consists of repetitive nucleotide sequences – One example includes telomeres at the end of the chromosomes

Repeated unit End of DNA molecule NUCLEOTIDE SEQUENCE OF A HUMAN TELOMERE Figure 12.13A

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• Barbara McClintock discovered that segments of DNA called transposons can move about within a cell’s genome

Figure 12.13B, C Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

12.14 Connection: The Human Genome Project is unlocking the secrets of our genes • The Human Genome Project involves: – genetic and physical mapping of chromosomes – DNA sequencing – comparison of human genes with those of other species Figure 12.14 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

OTHER APPLICATIONS OF DNA TECHNOLOGY 12.15 Connection: DNA technology is used in courts of law • DNA fingerprinting can help solve crimes Defendant’s blood

Blood from defendant’s clothes

Victim’s blood Figure 12.15A, B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

12.16 Connection: Recombinant cells and organisms can mass-produce gene products • Recombinant cells and organisms are used to manufacture useful proteins

Table 12.16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• These sheep carry a gene for a human blood protein that is a potential treatment for cystic fibrosis

Figure 12.16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

12.17 Connection: DNA technology is changing the pharmaceutical industry and medicine • Hormones, cancer-fighting drugs, and new vaccines are being produced using DNA technology – This lab equipment is used to produce a vaccine against hepatitis B

Figure 12.17 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

12.18 Connection: Genetically modified organisms are transforming agriculture • New genetic varieties of animals and plants are being produced – A plant with a new trait can be created using the Ti plasmid

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Agrobacterium tumefaciens DNA containing gene for desired trait

1

Ti plasmid

T DNA

Insertion of gene into plasmid using restriction enzyme and DNA ligase

Plant cell

2 Recombinant Ti plasmid

Restriction site

Introduction into plant cells in culture

3

Regeneration of plant

T DNA carrying new gene within plant chromosome

Plant with new trait

Figure 12.18A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• “Golden rice” has been genetically modified to contain beta-carotene – This rice could help prevent vitamin A deficiency

Figure 12.18B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

12.19 Connection: Gene therapy may someday help treat a variety of diseases • Techniques for manipulating DNA have potential for treating disease by altering an afflicted individual’s genes

Cloned gene (normal allele) 1 Insert

normal gene into virus Viral nucleic acid Retrovirus 2 Infect bone

marrow cell with virus

– Progress is slow, however

3 Viral DNA

inserts into chromosome

– There are also ethical questions related to gene therapy

Bone marrow cell from patient Bone marrow

Figure 12.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

4 Inject cells

into patient

RISKS AND ETHICAL QUESTIONS 12.20 Connection: Could GM organisms harm human health or the environment? • Genetic engineering involves some risks – Possible ecological damage from pollen transfer between GM and wild crops – Pollen from a transgenic variety of corn that contains a pesticide may stunt or kill monarch caterpillars Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 12.20A, B

12.21 Connection: DNA technology raises important ethical questions • Our new genetic knowledge will affect our lives in many ways • The deciphering of the human genome, in particular, raises profound ethical issues – Many scientists have counseled that we must use the information wisely Figure 12.21A-C Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings