General Methodology: L.M. Silver, Recordkeeping and Database Analysis of Breeding Colonies. P.A. Flecknell, Anesthesia and Perioperative Care. Germ Cells and Embryos: J.E. Cooke, I. Godin, C. French-Constant, J. Heasman, and C.C. Wylie, Culture and Manipulation of Primordial Germ Cells. M. Buehr and A.McLaren, Isolation and Culture of Primordial Germ Cells. J.J. Eppig and E.E. Telfer, Isolation and Culture of Oocytes. A.R. Bellve, Purification, Culture, and Fractionation of Spermatogenic Cells. A.R. Bellve, W. Zheng, and Y.S. Martinova, Recovery, Capacitation, Acrosome Reaction, and Fractionation of Sperm. R.A. Cardullo and H.M. Florman, Strategies and Methods for Evaluating Acrosome Reaction. J.A. Lawits and J.D. Biggers, Culture of Preimplantation Embryos. K. Sturm and P.P.L. Tam, Isolation and Culture of Whole Postimplantation Embryos and Germ Layer Derivatives. P.P.L. Tam, Histogenetic Potency of Embryonic Tissues in Ectopic Sites. Fertilization: J.W. Gordon, Micromanipulation of Gametes and Embryos. L.R. Fraser, In Vitro Capacitation and Fertilization. J.D. Bleil, In Vitro Fertilization. Gene Expression: Messenger RNA: K.B. Clegg and L. Piko, Radioisotope Labeling of UTP and ATP Pools and Quantitative Analysis of RNA Synthesis. K.D. Taylor and Lajos Piko, Quantitative Analysis of Specific Messenger RNAs by Hybridization Using RNA Probes R.A. Kinloch, R.J. Roller, and P.M. Wassarman, Quantitative Analysis of Specific Messenger RNAs by Ribonuclease Protection. M.Y. Arcellana-Panlilio and G.A. Schultz, Analysis of Messenger RNA. M.F. Gaudette, Q.P. Cao, and W.R. Crain, Quantitative Analysis of Specific Messenger RNAs in Small Numbers of Preimplantation Embryos. J. Singer-Sam and A.D. Riggs, Quantitative Analysis of Messenger RNA Levels: Reverse Transcription-Polymerase Chain Reaction Single Nucleotide Primer Extension Assay. F.J. Salles, W.G. Richards, J. Huarte, J.-D. Vassali, and S. Strickland, Microinjecting Antisense Sequences into Oocytes. D.G. Wilkinson and M.A. Nieto, Detection of Messenger RNA by in situ Hybridization to Tissue Sections and Whole Mounts. R.A. Conlon and B.G. Herrmann, Detection of Messenger RNA by in situ Hybridization to Postimplantation Embryo Whole Mounts. D. Sassoon and N. Rosenthal, Detection of Messenger RNA by in situ Hybridization. Gene Expression: Reporter Genes: M. Miranda and M.L. DePamphilis, Preparation of Injection Pipettes. M. Miranda, S. Majumder, M. Wiekowski, and M.L. DePamphilis, Application of Firefly Luciferase to Preimplantation Development. M. Vernet, C. Bonnerot, P. Briand, and J.-F. Nicolas, Application of LacZ Gene Fusions to Preimplantation Development. C. Bonnerot and J.-F. Nicolas, Application of LacZ Gene Fusions to Postimplantation Development. Gene Expression: Proteins: K.E. Latham, J.I. Garrels, and D. Solter, Two-Dimensional Gel Analysis of Protein Synthesis. M. Wiekowski and M.L. DePamphilis, One-Dimensional Gel Analysis of Histone Synthesis. C.A. Davis, Whole-Mount Immunohistochemistry. C. Simerly and G. Schatten, Techniques for Localization of Specific Molecules in Oocytes and Embryos. Gene Expression: Methylation: M. Zuccotti, M. Grant, and M. Monk, Polymerase Chain Reaction for the Detection of Methylation of a Specific CpG Site in the G6pd Gene of Mouse Embryos. G.P. Pfeifer, J. Singer-Sam, and A.D. Riggs, Analysis of Methylation and Chromatin Structure. Gene Identification: J.L. Rothstein, D. Johnson, J. Jessee, J. Skowronski, J.A. DeLoia, D. Solter, and B.B. Knowles, Construction of Primary and Subtracted cDNA Libraries from Early Embryos. G. Brady and N.N. Iscove, Construction of cDNA Libraries from Single Cells. Z. Larin, A.P. Monaco, S. Meier-Ewert, and H. Lehrach, Construction and Characterization of Yeast Artificial Chromosome Libraries. R.D. Cox, S. Meier-Ewert, M. Ross, Z. Larin, A.P. Monaco, and H. Lehrach, Genome Mapping and Cloning of Mutations Using Yeast Artificial Chromosomes. B.J. Gavin and A.P. McMahon, Cloning Developmentally Regulated Gene Families. D.P. Hill and W. Wurst, Screening for Novel Pattern Formation Genes Using Gene Trap Approaches. G. Friedrich and P. Soriano, Insertional Mutagenesis by Retroviruses and Promoter Traps in Embryonic Stem Cells. R.D. Sheppard and L.M. Silver, Two-Dimensional Gel Analysis of Repetitive DNA Families. Nuclear Transplantation: K.E. Latham and D. Solter, Transfer of Nuclei to Eggs and Embryos. S.C. Barton and M.A. Surani, Nuclear Transplantation. Transgenic Animals: Pronuclear Transplantation: J.W. Gordon, Production of Transgenic Mice. J.R. Mann and A.P. McMahon, Factors Influencing Efficient Production of Transgenic Mice. J.R. Mann, Surgical Techniques in Production of Transgenic Mice. M. Gendron-Maguire and T. Gridley, Identification of Transgenic Mice. Transgenic Animals: Embryonic Stem Cells and Gene Targeting: S.J. Abbondanzo, I. Gadi, and C.L. Stewart, Derivation of Embryonic Stem Cell Lines. C.L. Stewart, Production of Chimeras between Embryonic Stem Cells and Embryos. R. Ramirez-Solis, A.C. Davis, and A. Bradley, Gene Targeting in Embryonic Stem Cells. F. Kontgen and C.L. Stewart, Simple Screening Procedure to Detect Gene Targeting Events in Embryonic Stem Cells. B. Sauer, Manipulation of Transgene by Site-Specific Recombination: Use of Cre Recombinase. M.V. Wiles, Embryonic Stem Cell Differentiation In Vitro. K.J. McLaughlin, Production of Tetraploid Embryos by Electrofusion. Lineage Analysis: C.L. Cepko, E.F. Ryder, C.P. Austin, C. Walsh, and D.M. Fekete, Lineage Analysis Using Retroviral Vectors. Author Index. Subject Index.