Animal Cloning: A Risk Assessment/Preface

by US Food and Drug Agency

The following Risk Assessment is the result of a multi-year effort by staff from the US Food and Drug Administration’s (FDA’s) Center for Veterinary Medicine (CVM or the Center). Since the late 1990s, CVM has been gathering data and meeting with clone producers and other stakeholders interested in cloning to discuss the safety and regulatory implications of somatic cell nuclear transfer (SCNT), the process most commonly used to generate animal clones during this time period. In the fall of 2000, CVM tasked the National Academy of Sciences (NAS) to perform an independent, scientific review of the available data on the safety of cloning, including holding a public meeting to identify science-based concerns and elicit data and information on clones and their food products from the scientific community. In July of 2001, the Center issued a CVM Update requesting that clone producers not introduce meat or milk from clones or their progeny into food or feed until the NAS report had been completed, and the agency had had a chance to complete its own review of the safety of those food products.1

In October of 2002, NAS issued its report "Animal Biotechnology: Science-Based Concerns." Following an overview of the available data on animal clones, the report indicated that the most likely mechanism for generating hazards to clones would stem from reprogramming of the donor cell genome, and that any harms that might result from that reprogramming would be observed early in a clone’s development. They further noted that there were no published data comparing the composition of meat or milk from clones with that from conventionally-bred animals. Nonetheless, the report concluded that there is "no evidence that food products derived from adult somatic cell clones or their progeny pose a hazard (i.e., there is no evidence that they present a food safety concern)" (page 65).

This Risk Assessment is CVM’s subsequent independent analysis of all of the available data relevant to assessing the health of clones and their progeny (and other animals involved in the cloning process) or food consumption risks resulting from edible products from these animals. In order to make the Risk Assessment as transparent as possible, all of this information is available to the public, either by virtue of its publication in peer-reviewed journals, or by "publication" in this risk assessment. We have actively sought independent peer-review of these data by providing all of the data in raw form (not summaries) either in the text of the risk assessment or in appendices. In addition, we have also described the means by which the methodology was developed to facilitate peer-review by risk assessors.

CVM has attempted to be as comprehensive as possible about identifying and using all of the relevant data in its analysis. We have performed extensive literature reviews, engaged in conversations with scientists involved in cloning animals, and requested data on animal health and food composition from scientists, breeders, and food producers. Unpublished data were provided to us in raw, unanalyzed form, which we subsequently analyzed. CVM determined whether a particular publication or dataset was relevant to the analysis. These judgments were framed by the two overarching objectives of the Risk Assessment: determining whether cloning poses any health risks to the animals involved in the cloning process, and whether any hazards arise during the development of clones or their progeny that may pose food consumption risks.

Literature searches for the draft version of the Draft Risk Assessment ceased in early 2006. For the final version of the Risk Assessment, we have conducted updated literature searches (through mid-year 2007), thoroughly reviewed hundreds of additional relevant papers from the peer-reviewed literature, and incorporated this information into the Risk Assessment. The final version also includes additional, unpublished data that were submitted to CVM after the release of the Draft Risk Assessment. We reviewed all of the public comments that we received on the Draft Risk Assessment and associated documents. Careful consideration was given to relevant, science-based information in the comments, and parts of the Risk Assessment have been revised in response to these comments.

In addition to understanding the Risk Assessment’s goals, it is equally important to understand what it does not consider. It does not attempt to address the question of whether clones are "normal;" rather it concentrates on identifying the risks that cloning poses to animal health or to humans and animals consuming food derived from clones and their progeny. It also does not attempt to explore issues such as the influence of different donor cell types or cell cycle stages in the "success rate" for producing clones, or the degree to which clones are more or less identical at the phenotypic level. Studies addressing these questions have been used, however, when they provided data useful to the identification of hazards or risks. Similarly, the Risk Assessment does not attempt to parse out the relative effectiveness of different cloning techniques or different laboratories in generating live animals. Results of cloning in species not commonly used for food have been employed only as they have utility as model systems (e.g., mice as models for livestock). Uncertainties associated with those models have been identified.

It is important to note that this Risk Assessment is a scientific document that provides a framework by which science-based questions regarding animal health and food consumption risks are evaluated. CVM recognizes that cloning raises many ethical and economic concerns. These issues may be important to members of the public, however, they are not within FDA’s mission and therefore not within the purview of this Risk Assessment.

Finally, the measures we will take to manage the risks associated with cloning and our recommendations regarding the use of clones or their progeny as food or feed are not included in the Risk Assessment, but are addressed in the accompanying Risk Management Plan and Guidance for Industry.