Biotechnology and Bioinformatics (1+1)

2.2.1 Introduction

An organism that has a foreign or modified gene transfer red to its genome using the in vitro gene tic techniques is called a genetically modified organism (GMO) or a transgenic organism.

• Gordon et al. (1980) produced transgenic animals by microinjection of clone d DNA into the pronucleus of fertilized eggs at the one-cell stage.
• Palmiter et al. (1982) introduced growth hormone gene into mice and produced giant mouse of 44 gms whereas, normal grows upto only 29 g.
• Attempts to produce transgenic fish began in the mid-1980s. Maclean and Talwar (1984) reported microinjection of cloned DNA into rainbow trout (Oncorhynchus mykiss) eggs.

Zhu et al. (1985) microinjected fertilized eggs of goldfish with metallothionein promoter fused with the human growth hormone gene.

Transgenic technology has been successfully used to develop fast-growing super-fish stocks for

• human consumption,
• to produce pharmaceuticals,
• to test water contamination in both developed and developing countries.
• Several laboratories now have GM fish with increased growth performance caused by extra copies of GH genes. So far, fast growing fish by transferring growth hormone gene have been developed for several aquacultural species.
• Several species including loach, common carp, crucian carp, Atlantic salmon, channel catfish, tilapia, medaka and northern pike containing either human, bovine, or salmonid growth hormone genes grew 10-80% faster than non-transgenic fish in aquaculture conditions.
• Some of the experiments demonstrated that growth can be enhanced through transgenesis from 10% up to an incredible 30-fold.