Impacts of Contemporary
 Biotechnology on Animal Science

 Roger M. Weppelman
 Merck, Sharp & Dohme Research Laboratories
 Rahway, New Jersey


 INTRODUCTION

 The term "Biotechnology" is not easily defined. By the more inclusive
definitions, animal science itself qualifies as one of the oldest (and most
successful) of the biotechnologies. Rather than attempting to define "Bio-
technology," I will simply state at the onset that the scope of this manu-
script will be restricted to those aspects of contemporary animal science
which have evolved from one or more of the following three papers in the
scientific literature:
 1. Chung and Cohen (1974). This paper describes the use of a restriction
 enzyme to create a functional genetic element bearing genes from
 two species of bacteria and thereby marks the beginning of genetic
 engineering.
 2. Kohler and Milstein (1975). The authors fused a normal mouse spleen
 cell secreting a single type of antibody with an immortal mouse
 myeloma cell to produce the first hybridoma, which continued to
 secrete antibody and was immortal. This was the start of hybridoma
 technology and monoclonal antibodies.
 3. Palmiter et al. (1982). These authors describe the creation of
 transgenic mice. Strictly speaking, this was not the first creation of
 transgenic mice, but because the gene used was beautifully engi-
 neered, because the technique was elegant and widely applicable,
 and because the results were truly dramatic, this paper marks the
 beginning of transgenic animals.


 GENETIC ENGINEERING

 Restriction enzymes are the basis for genetic engineering because of
their unique ability to cleave double stranded DNA in such a way that the
pieces can be readily rejoined (Maniatis et al., 1982; Rodriquez and Tait,
1983). Hybrid genes can be engineered by cleaving two unrelated chromo-