Marmoset (Callithrix jacchus). Picture by Manfred Werner/Tsui
Japanese researchers from the Central Institute for Experimental Animals have generated the first transgenic non-human primates in which germline transmission has been confirmed, as reported today in an article published in Nature. In this publication, Erika Sasaki and co-workers describe the generation of transgenic marmosets (Callithrix jacchus), using an animal strain derived and maintained in this research institute since 1980. The transgenic marmosets were produced by lentiviral transgenesis, using a self-inactivating lentivirus carrying EGFP as a reporter gene. Germline transmission was demonstrated by in vitro ferlilization (IVF), using transgenic sperm from one of the obtained male transgenic marmoset founders for fertilizing, in vitro, marmoset wild-type oocytes and transferring the resulting embryos to a female for gestation to term.
There have been other previous reports about transgenic non-human primates but this is the first experiment demonstrating, unequivocally, germ-line transmission of a transgene inserted into a primate genome. This achievement is a milestone in the animal transgenesis field, and with no doubt will trigger an intense social debate about the biomedical and bioethical implications, potential benefits and associated risks. The use of non-human primates for animal modelling of human diseases is a matter of debate in many countries. From a scientific point of view, it appears that aiming to reproduce the course of severe and devastating human diseases in an animal that is closer tu us than rodents is an impressive technological and instrumental achievement, which might benefit our current understanding about how these diseases are established, how they progress and how effectively innovative therapies can be devised. From a bioethical point of view, the stable genetic modification of an animal species belonging to a group of mammals where we, human beings, are also included is prone to discussions and might be not supported by everyone. In my opinion, the role of scientists and professionals in the animal transgenesis field would be to contribute, with our expertise and understanding of these techniques, to openly discuss all aspects of these experiments, their advantages, problems, benefits and risks, to assess every single aspect while taking always into due consideration the associated animal welfare issues that are bound to any experimentation with animals.