Benefits of Nuclear Transfer
Nuclear transfer technology involves transferring the complete genetic material from the nucleus of a cultured donor cell to a mature recipient egg whose own nucleus has been removed. The resulting offspring are genetically identical to the founder animal who supplied the donor nucleus (see diagram).

The technique also offers PPL the potential to derive transgenic animals from cultured cells. These cells can be genetically manipulated to obtain the desired characteristics for protein production and, through nuclear transfer technology, each will develop into a genetically identical transgenic sheep or cow.  The precision of these modifications can be enhanced with PPL's unique 'gene targeting system' which is capable of introducing DNA at a specific site in the host chromosome.

PPL's former approach, based on DNA microinjection, has already allowed the economical production of a wide range of proteins and peptides from the milk of transgenic animals. However, nuclear transfer technology and gene targeting bring additional significant benefits.

	All animals born will be transgenic.
	Faster development of a production flock or herd, significantly reducing the time to production of protein or peptide. Where it would normally require 44 months to reach production flock status in sheep, (78 months in cows), nuclear transfer technology can reach production flock status in 18 months for sheep, (33 months for cows).
	Earlier availability of product, accelerating progress to clinical trials.
	The selective removal of gene(s), replacing them with the desired human equivalents.
	Increased expression levels of product (by targeting inserted genes to sites of high expression).
	Cellular-level analysis of clones allowing pre-selection for optimal protein expression.

Research is already underway at PPL both in the UK and US to apply nuclear transfer technology to the production of transgenic animals for the manufacture of pharmaceutical and nutritional proteins. PPL has already demonstrated success in applying nuclear transfer in sheep and in cows with the births of "Polly" and "Mr Jefferson" respectively.

Nuclear transfer technology is covered by granted patents and patent applications filed by the Roslin Institute. The two patent applications relating to Cloning and Nuclear Transfer (publications WO 97/07668 and WO 97/07669; priority date 31 August 1995) are licensed to PPL in the field of production of proteins for pharmaceutical and nutraceutical use in the milk of transgenic ruminants and rabbits.