Part Four - Molecular Biology: The Genome in Action 331

16.  Recombinant DNA and Biotechnology 352

16.1 How Are Large DNA Molecules Analyzed? 353 Restriction enzymes cleave DNA at specific sequences 353 Gel electrophoresis separates DNA fragments 354 DNA fingerprinting uses restriction analysis and electrophoresis 355 The DNA barcode project aims to identify all organisms on Earth 356 16.2 What Is Recombinant DNA? 358 16.3 How Are New Genes Inserted i nto Cells? 359 Genes can be inserted into prokaryotic or eukaryotic cells 359 Vectors carry new DNA into host cells 359 Reporter genes identify host cells containing recombinant DNA 361 16.4 What Are the Sources of DNA Used in Cloning? 362 Gene libraries provide collections of DNA fragments 362 cDNA libraries are constructed from mRNA transcripts 363 DNA can be synthesized chemically in the laboratory 363 DNA mutations can be created in the laboratory 363 16.5 What Other Tools Are Used to Manipulate DNA? 364 Genes can be inactivated by homologous recombination 364 Antisense RNA and interference RNA can prevent the expression of specific genes 365 DNA chips can reveal DNA mutations and RNA expression 365 16.6 What Is Biotechnology? 367 Expression vectors can turn cells into protein factories 367 Medically useful proteins can be made by biotechnology 368 DNA manipulation is changing agri¬culture 369 There is public concern about bio¬technology 371