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Stem cell transgenesis
By using a stem cell as the vehicle to introduce the exogenous gene, the stem cell can conform to the cell type around it, expressing the newly introduced gene. Embryonic cells (or cells that have been coaxed back into a stem cell state) are modified and selected for a particular trait or gene, and then injected into a developing blastocyst in vivo, resulting in modified offspring. Experiments using embryonic stem cells have shown that 10% of the injected blastocysts express the chimeric genes onced carried to term, a similar effectiveness to microinjection and retrovirus methods. There are some benefits to using stem cells as the vehicle, such as the ability to completely screen the condition and traits of the injected cell, so scientists can better keep track of the traits that are being introduced.

Stem cell transgenesis can be divided into three parts, named for the utilized stem cells' ability to differentiate: Multipotent, Pluripotent, and Totipotent.

Multipotent stem cell transgenesis
Multipotent stem cells can only differentiate into a limited number of therapeutically useful cell types, nevertheless their safety and relative lack of complexity have resulted in the vast majority of current personalized stem-cell therapy involving multipotent stem cells (typically mesenchymal stem cells from adipose tissue).

Pluripotent stem cell transgenesis
Transgenic vectors can be delivered randomly, or targeted to a specific genomic location, such as a safe harbor. Scientists have performed research and technology development to provide the tools necessary to permit safe and effective pluripotent stem cell (PSC) transgenesis.

Totipotent stem cell transgenesis
The manipulated gene construct is inserted into totipotent stem cells, cells which can develop into any specialized cell. Cells containing the desired DNA are incorporated into the host’s embryo, resulting in a chimeric animal. Unlike the other two methods of injection which require live transgenic offspring for testing, embryonic cell transfer can be tested at the cell stage.