DOCSLIB.ORG

Chimeras Keep Courting Controversy Elie Dolgin, Science Writer

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Chimeras Keep Courting Controversy Elie Dolgin, Science Writer CORE CONCEPTS CORE CONCEPTS Chimeras keep courting controversy Elie Dolgin, Science Writer Last autumn, the US National Institutes of Health announced it would not fund any research that entails introducing human pluripotent stem cells into early embryos of another species, including laboratory stal- warts, such as mice, or larger animals like pigs. The agency said it wanted a chance to conduct a formal policy review on these interspecies “chimeras.” The backlash from the scientific community was swift. A group of leading stem cell experts wasted no time in condemning the move in Science as “a threat to progress” (1). “It was a ham-handed approach,” says Christopher Scott, a bioethicist at Baylor College of Medicine in Houston, and one of 11 authors of the Science commen- tary. “That’s a really terrible way to do science policy because it just creates panic and makes scientists uncer- — ” Even as they raise ethical concerns, chimeras like this one tain about their lines of inquiry. human cells (red) growing inside a blastocyst-stage pig In August, the NIH reversed course on the ban and embryo—continue to pique some biomedical researchers’ proposed allowing funding for studies involving chi- interest. Image courtesy of Juan Carlos Izpisua ´ Belmonte. meras, with some added provisos. Still, according to Scott, the 10.5-month funding hiatus was long enough The last couple of decades have also seen the “ to put at risk some big and important areas of re- development of chimeras in larger farm animals and ” search in developmental biology, disease modeling, primates, including pigs with human blood, sheep with and regenerative medicine. part-human livers, and monkeys with human neural ’ It s the latest twist in a decades-long saga for the tissue. Through it all, there’s been opposition. organismal and cellular contrivances that some con- Twenty years ago, Stuart Newman, a developmental sider to be fraught with ethical barriers, and others see biologist at New York Medical College, and activist as a practical means toward key research insights and Jeremy Rifkin sought to patent the process of creating “ ” disease cures. There was always controversy, says chimeras from the embryonic cells of humans and Esmail Zanjani, an experimental hematologist at the animals. If they won the patent, Newman and Rifkin ’ University of Nevada, who developed the world s first planned to prevent others from commercializing hu- – human sheep chimeras in the mid-2000s. man–animal combinations. If they lost—which they Already, since 2009, the NIH has prohibited fund- eventually did—it would set legal precedent that these ing for experiments that put human stem cells into the hybrids were not patentable and thereby prevent embryos of our close primate relatives, or studies in which others from profiting on a technique that they found chimeras of any species that have human reproductive morally objectionable. “Either way,” says Newman, cells are allowed to breed. These rules will likely stand “there was something to be gained.” with minor tweaks, although the agency is considering an Chimera research would continue to court contro- additional layer of scrutiny. versy as it entered the political fray. President Bill ClintonspokeoutaftertheMassachusetts biotechnology Science, Ethics, Politics company Advanced Cell Technology claimed in 1998 to The chimeras of Greek mythology were monstrous have created hybrid cow–human embryos. “I am deeply creatures possessing parts from multiple animals. In troubled by this news of experiments involving the research, the “chimera” label alludes to a variety of mingling of human and nonhuman species,” Clinton approaches. Infectious disease scientists have been wrote to the National Bioethics Advisory Commission in making mice with human immune systems for close to a request for an inquiry (2). 30 years, and cancer biologists have been implanting President George W. Bush later urged the passage of human tumors into mice for even longer. a bill to ban outright the creation of all human–animal 11984–11985 | PNAS | October 25, 2016 | vol. 113 | no. 43 www.pnas.org/cgi/doi/10.1073/pnas.1615787113 Downloaded by guest on September 24, 2021 chimeras, something he described in his 2006 State species. “Anything where you mix tissues of different of the Union address as one of “the most egregious organisms you can call a chimera, but these embryo abuses of medical research” (3). (Republican Kansas chimeras are something different,” says Newman. Senator Sam Brownback introduced the “Human “You’re really making the chimera when the species Chimera Prohibition Act” in 2005, but it went identity of the organism is being formed.” nowhere.) Additional Scrutiny Chimeric Menagerie Under a proposal outlined in August, an internal NIH For the most part, all of the chimeric creations of re- committee will review any and all applications to make cent decades have involved injecting human cells into human chimeras from early embryos of any mammalian already-born or fetal animals. The reason: the types of species (up through and including the gastrulation stage human stem cells available to researchers just didn’t when the three fundamental tissue layers start to appear). comingle or engraft well to early animal embryos. The panel will also oversee any studies, excluding those That started to change last year with the discovery with rodents, in which human cells might alter the brain of a new type of human pluripotent stem cell that can in some way, regardless of when the cells are introduced. efficiently cross the species barrier in mouse embryos Carrie Wolinetz, associate director for science policy that are about a week old (4). According to Juan at NIH, says the agency was not responding to any Carlos Izpis ´uaBelmonte, the developmental biologist specific project proposal or grant application to work at the Salk Institute for Biological Studies who dis- with early embryos or to create large-animal models with covered those cells, his team has since generated human brains. “But we did see investigators saying this even newer types of stem cells that can mix with ear- was their plan for the future—the kind of ‘next step’— lier-stage embryos of livestock. andwewantedtomakesurewegotoutaheadofthat.” The latest advances in genome-editing tools, such Wolinetz rejects the notion that any politics are at as CRISPR-Cas9, have also empowered scientists to play. The NIH’s policy, she says, is simply getting enrich the human contribution of particular tissues in out ahead of the research as the science evolves. “It the resulting creatures. That confluence of cutting- allowed us to not be disruptive, and then really talk to edge technologies has given chimeras “more of a the scientists and really think about what policy makes plausible route to widespread clinical use,” says Hank sense given where the science is,” Wolinetz says, “and Greely, director of the Center for Law and the Bio- we don’t usually have the luxury to do that.” sciences at Stanford Law School. Many researchers, however, see the additional regu- Several research teams around the world are now lations put forward by the NIH as superfluous. As actively trying to grow human hearts, livers, pancreases, first proposed in a 2005 National Academies report and other organs inside pigs and sheep. By knocking (5), institutional oversight committees in the United out certain genes in the animals’ DNA, scientists can States now routinely review any research involving make embryos that are incapable of forming a specific human pluripotent stem cells that could be ethically tissue. The researchers can then insert human pluripo- problematic (a review of most in vitro induced plurip- tent stem cells that should fill in the missing organ. By otent stem cells work, for example, was not deemed gestating the embryo in a surrogate sow or ewe, they necessary). And there’s nothing in the work of Izpisua ´ hope to harvest the organs for human transplantation. Belmonte or others that is pushing any new ethical “It’s still very early-stage work: proof-of-principle boundaries, asserts Greely. that this could even be possible,” says Izpisua ´ Belmonte, “The concerns are not about growing a human gall one of the pioneers of this line of research (which has bladder or pancreas in a pig. Very few people care been supported to date with non-NIH funds). about that,” he says. “It’s about brains, it’s about Izpis ´ua Belmonte is quick to point out that his gametes...And I think the existing mechanisms were team, which includes collaborators at the University of fine to take care of the concerns that people have.” California, Davis, and in Spain, currently destroys their For many, chimeras provoke disgust, crossing a human–pig chimeras after just 28 days, well short of a sacrosanct ethical line. But decades after these hu- pig’s 114-day gestation. And the researchers make man–animal hybrids first sparked controversy in the sure to check that no human cells are contributing to research realm, scientists still see the potential for life- brain or reproductive tissues. “It is a cautious, thoughtful, saving, tailor-made tissues and organs. “There’s this and stepwise approach,” Izpisua ´ Belmonte says. huge unmet medical need for transplants,” says Scott, But critics of the research still worry about the ways “and what might be done in animals [with chimeras] that new technologies are blurring the lines between could really help with this critical crisis.” 1 Sharma A, et al. (2015) Lift NIH restrictions on chimera research. Science 350(6261):640. 2 Clinton B (1998) President Clinton’s Request Re: Embryonic Stem Cells. Available at https://bioethicsarchive.georgetown.edu/nbac/ transcripts/nov98/day1_stemcell.htm. Accessed September 29, 2016. 3 Bush GW (2006) State of the Union Address. Available at https://georgewbush-whitehouse.archives.gov/stateoftheunion/2006/. Accessed Spetember 29, 2016.
Load more

Recommended publications
  • The Human Chimera: Legal Problems Arising from Individuals with Multiple Types of Dna
    Seton Hall University eRepository @ Seton Hall Law School Student Scholarship Seton Hall Law 5-2-2014 The umH an Chimera: Legal Problems Arising From Individuals with Multiple Types of DNA Robert Russell Granzen Follow this and additional works at: https://scholarship.shu.edu/student_scholarship Recommended Citation Granzen, Robert Russell, "The umH an Chimera: Legal Problems Arising From Individuals with Multiple Types of DNA" (2014). Law School Student Scholarship. 485. https://scholarship.shu.edu/student_scholarship/485 THE HUMAN CHIMERA: LEGAL PROBLEMS ARISING FROM INDIVIDUALS WITH MULTIPLE TYPES OF DNA Robert Granzen INTRODUCTION Science continually changes, and with it our understanding of the human body. While some scientific developments are limited in scope, others have widespread effects. Scientists have just recently begun understanding the range of effects chimerism in humans can have. Chimerism, originally associated with hermaphrodites having both male and female sexual organs, is much more common than originally thought. As chimerism becomes more common, so do individuals with separate and distinct deoxyribonucleic acid (DNA) strands in their bodies. Most individuals are unaware of their chimeric genetic code and most will likely never know. Because of the inherent difficulty of testing for chimerism, many problems are presented to legal system. Part I of this article will begin with the history of human chimeras. The section will then describe the ways in which chimeras are formed. The section will discuss the most common form of chimerism in humans--fetal cell microchimerism (FMC). FMC occurs when cells are transferred from baby to mother or mother to baby via the umbilical cord.1 Studies have shown that mothers may keep cells from their children for years after giving birth.2 Moreover, cells can be exchanged between twins while inside the uterus.3 Secondly, the section will describe the process of embryo fusion, which can cause tetragametic chimerism.
    [Show full text]
  • Patentability of Human-Animal Chimeras Ryan Hagglund
    Santa Clara High Technology Law Journal Volume 25 | Issue 1 Article 4 2008 Patentability of Human-Animal Chimeras Ryan Hagglund Follow this and additional works at: http://digitalcommons.law.scu.edu/chtlj Part of the Law Commons Recommended Citation Ryan Hagglund, Patentability of Human-Animal Chimeras, 25 Santa Clara High Tech. L.J. 51 (2012). Available at: http://digitalcommons.law.scu.edu/chtlj/vol25/iss1/4 This Article is brought to you for free and open access by the Journals at Santa Clara Law Digital Commons. It has been accepted for inclusion in Santa Clara High Technology Law Journal by an authorized administrator of Santa Clara Law Digital Commons. For more information, please contact [email protected]. PATENTABILITY OF HUMAN-ANIMAL CHIMERAS Ryan Hagglundt Abstract The chimera was a mythological creature with a lion 's head, goat's body, and serpent's tail. Because of recent advances in biotechnology, such permutations on species are no longer the stuff of myth and legend The term "chimera " has come to describe a class of genetically engineered creatures composed of some cells from one species, which thus contain genetic material derived entirely from that species, and some cells from another species, containing only genetic material from that species. Scientists have created a goat- sheep chimera or "geep" which exhibits physical characteristicsof both animals. Likewise, scientists have also used the tools of modern molecular biology to create human-animal chimeras containing both human and animal cells. While none of the human-animal chimeras hitherto created have exhibited significant human characteristics,the synthesis of human-animal chimeras raises significant ethical concerns.
    [Show full text]
  • My Attempt to Patent a Human-Animal Chimera
    No 27 - avril-mai 2006 My attempt to patent a human-animal chimera In 1997, with the support of the social critic Jeremy Rifkin of the Foundation on Economic Trends in Washington, D.C., Professor Stuart A. Newman undertook to apply for a patent on embryos and full- term creatures containing human along with nonhuman cells – so-called “chimeras” that he had no intention of producing... Stuart A. Newman* In 1997, with the support of the social critic Jeremy Rifkin of the Foundation on Economic Trends in Washington, D.C., I undertook to apply for a patent on embryos and full-term creatures containing human along with nonhuman cells – so-called “chimeras”. The public had only just learned (to widespread surprise) about the cloning of Dolly the sheep and the announcement of the production of versatile and controversial embryonic stem (ES) cells from human embryos was still a year in the future. In those innocent days less than a decade ago the prospect of fabricating creatures that were part-human and part-beast would have appeared to most people like something out of Greek mythology or the pages of a fantasy novel. Indeed, it had been a century since the British writer H.G. Wells had published “The Island of Dr. Moreau”, the story of a visionary scientist whose well-motivated experiments along these lines led to death and destruction. Still, in the last years of the 20th century, such quasi-humans were unknown outside of works of fiction. Nonetheless, as a developmental biologist whose work requires close tracking of the scientific literature, I knew that such things were feasible.
    [Show full text]
  • Chimera Proposal
    Frequently Asked Questions on Chimera Proposal 1) What are the potential benefits of this research? Research using animal models containing human cells is certainly not new. For example, the introduction of human stem cells into mice has been used to validate and characterize different types of stem cells. Some scientists hope the human cells will develop into specific tissues or organs for potential transplant purposes, or for drug testing. Other researchers are exploring the developmental nature of particular types of human cells, which may yield important insight into human biology and disease development. Animal models with human cells in the brain can be used to study many human brain diseases, including Parkinson’s, Alzheimer’s, and schizophrenia, and may be useful models for testing new drugs. Furthermore, these animal models could be used to study whether introduction of therapeutic human cells can improve outcomes for diseases that are caused by the death or dysfunction of neural or other brain cells, prior to testing the cells in people. 2) What kind of research does NIH anticipate funding in the future? This will depend on the ideas of the research community, but if researchers are successful in the development of animal models with human tissues or organs, those animal models could have many research applications for studying disease development and testing new therapeutics, as well as a possible source of tissues or organs for transplant. 3) Does NIH currently have any policy in this research area? Yes. The NIH Guidelines for Human Stem Cell Research prohibit the introduction of human pluripotent cells into non-human primate blastocyst-stage embryos, and prohibit the breeding of animals where the introduction of human pluripotent cells may have led to human sperm or human eggs being produced in the animal.
    [Show full text]
  • An Interesting Case of Chimera: Inconclusive BRCA Analysis Due To
    Case Report iMedPub Journals 2018 www.imedpub.com Journal of Genomics & Gene Study Vol.1 No.1:3 An Interesting Case of Chimera: Inconclusive Bowers AW*, Monteverde A, BRCA Analysis due to Two Distinct Genetic Keckeisen G and Kapenhas E Profiles in a Single Patient Ellen Hermanson Breast Center, Southampton, New York, USA Abstract *Corresponding author: Anne Wills Bowers Background: Our case study proposes an explanation for the inconclusive BRCA testing we received on one of our patients. The BRCA analysis was inconclusive [email protected] due to the specimen being chimeric, or having two distinct genetic profiles. We propose the Vanishing Twin theory as the most probable explanation. We have Ellen Hermanson Breast Center, found no other reported cases of chimera linked to Vanishing Twin Syndrome in Southampton, New York, USA. the literature. Methods: In this case report, we have described the presentation and operative Tel: +1 631-726-8400 course of a single patient of our Breast Center in 2017 to help define the setting of our unique BRCA analysis result. Findings: We have also done an extensive literature search in an attempt to Citation: Bowers AW, Monteverde A, understand the implications of the BRCA analysis result in a chimeric patient. Keckeisen G, Kapenhas E (2018) An However, our search was not satisfied by any direct evidence. We can only Interesting Case of Chimera: Inconclusive conclude that the Vanishing Twin theory is the most likely explanation of chimera BRCA Analysis due to Two Distinct Genetic in this single patient. Profiles in a Single Patient. J Genom Gene Study Vol.1 No.1:3 Conclusions: We were unable to find any direct explanation for our results but we do propose this as an interesting case, as chimera is rare.
    [Show full text]
  • Human-Nonhuman Chimeras: a Regulatory Proposal on the Blurring of Species Lines Nicole E
    Boston College Law Review Volume 45 Article 3 Issue 3 Number 3 5-1-2004 Human-Nonhuman Chimeras: A Regulatory Proposal on the Blurring of Species Lines Nicole E. Kopinski Follow this and additional works at: http://lawdigitalcommons.bc.edu/bclr Part of the Science and Technology Law Commons Recommended Citation Nicole E. Kopinski, Human-Nonhuman Chimeras: A Regulatory Proposal on the Blurring of Species Lines, 45 B.C.L. Rev. 619 (2004), http://lawdigitalcommons.bc.edu/bclr/vol45/iss3/3 This Notes is brought to you for free and open access by the Law Journals at Digital Commons @ Boston College Law School. It has been accepted for inclusion in Boston College Law Review by an authorized editor of Digital Commons @ Boston College Law School. For more information, please contact [email protected]. HUMAN-NONHUMAN CHIMERAS: A REGULATORY PROPOSAL ON THE BLURRING OF SPECIES LINES Abstract: The chimera of modern biotechnology is defined broadly as a single organism composed of a mixture of materials from two or more organisms possessing distinct genetic backgrounds. Unlike the United States, which does not regulate chimeras directly, Canada has responded to the unregulated pursuit of chimera technology by banning certain chim- eras as part of comprehensive legislation designed to regulate human reproductive technologies. In 2001, the Canadian Parliament passed the Assisted Human Reproduction Act despite criticism urging greater legis- lative justification for the Act's provisions and modification to its statutory definitions, Because current regulatory mechanisms in the United States, including patent law and administrative oversight, fail to regulate chimera technology, the United States should enact new legislation, using Canada's legislation as a model, to prohibit embryonic chimeras and to regulate other human-nonhuman combinations.
    [Show full text]
  • 3257.Full.Pdf
    (CANCER RESEARCH 51. 3257-3260. June 15. 1991] Strain Specific Sensitivity to Diethylnitrosamine-induced Carcinogenesis Is Maintained in Hepatocytes of C3H/HeN^C57BL/6N Chimeric Mice1 Gang-Hong Lee,2 Kimie Nomura, Hiroaki Kanda, Moriaki Kusakabe, Atsushi Voshiki, Teruyo Sakakura, and Tomoyuki Kitagawa Department of Pathology, Cancer Institute, Toshima-ku, Tokyo 171)/ii-H. L, K. N., H. A'., 7".A'./, anil Laboratory of Cell Biology, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKE.\), Ibaraki 305 [M. A".,A. Y., T. S.J, Japan ABSTRACT derived neoplasms (21 of 23) in their results actually reflected numbers or rather only differences in growth rate of initiated The C3H/HeN (C3H) and C57BL/6N (C57) mouse strains are known, or preneoplastic lesions of C3H and C57 types in the chimeric respectively, for their high and low susceptibility to both spontaneous mouse liver. and chemically induced hepatocarcinogenesis. The present study was aimed at elucidating whether this difference is dependent on intrinsic It has been shown in rodent hepatocarcinogenesis that the features of the target hepatocytes or the in vivo milieu and associated effects of initiation and promotion can be reliably and quanti growth promoting factors to which the cells are exposed. C3H«-»C57tatively estimated by scoring altered cell lesions, which are the chimeric mice were produced and given injections of diethylnitrosamine proliferated progenies of carcinogen-initiated cells (6-8). For (20 ¿ig/gbodyweight) at the age of 15 days. The animals were sacrificed example, previous studies have shown that both the number 6 or 9 months thereafter, and the numbers and sizes of altered cell lesions and size of microscopically detectable lesions induced by DEN were scored.
    [Show full text]
  • An Interspecies Barrier to Tetraploid Complementation and Chimera Formation
    www.nature.com/scientificreports OPEN An interspecies barrier to tetraploid complementation and chimera formation Received: 19 February 2018 Tomoyuki Yamaguchi 1, Hideyuki Sato1, Toshihiro Kobayashi1,5, Megumi Kato-itoh1, Accepted: 3 October 2018 Teppei Goto 2, Hiromasa Hara2, Naoaki Mizuno1, Ayaka Yanagida1,6, Ayumi Umino1, Published: xx xx xxxx Sanae Hamanaka1, Fabian Suchy4, Hideki Masaki1, Yasunori Ota3, Masumi Hirabayashi2 & Hiromitsu Nakauchi1,4 To study development of the conceptus in xenogeneic environments, we assessed interspecies chimera formation as well as tetraploid complementation between mouse and rat. Overall contribution of donor PSC-derived cells was lower in interspecies chimeras than in intraspecies chimeras, and high donor chimerism was associated with anomalies or embryonic death. Organ to organ variation in donor chimerism was greater in interspecies chimeras than in intraspecies chimeras, suggesting species- specifc afnity diferences among interacting molecules necessary for organogenesis. In interspecies tetraploid complementation, embryo development was near normal until the stage of placental formation, after which no embryos survived. Advances in chimera and stem cell technology has provided intriguing tools with many basic and translational applications. Since chimeras have at least two cell populations with diferent genetic backgrounds, they can be used to compare cell potency and function, or probe signaling pathways during development. Generation of chi- meras using PSCs is well-established for intraspecies applications1–7, however is more difcult in an interspecies setting. One exciting interspecies application exploits mouse-rat chimerism to generate PSC-derived organs by blastocyst complementation8. Injection of rat induced PSCs (iPSCs) into Pdx1−/− mouse blastocysts successfully generated a rat pancreas in a mouse, demonstrating that PSCs can contribute to xenogenic embryo development with postnatal survival.
    [Show full text]
  • Chimeric Brains Consisted of Primatologists and Other Scientists, Ethicists, and Lawyers
    Chimeras Definition Ethical Issues Links Suggested Reading End Notes Definition: What are Chimeras? How and why are they produced? Chimeras are animals composed of cells that originate from two (or more) different species. In the research lab, chimeras are created by introducing cells from one species into the developing embryo or fetus of another. (The name chimera comes from Greek mythology and describes a creature with the head of a lion, the body of a goat, and the tail of a serpent). The first chimeras helped scientists understand questions about developmental biology. A sheep-goat chimera, created in 1984, had the head of a goat and the woolly coat of a sheep.i Chicken-quail chimeras have also been successfully developed.ii,iii Sheep-Goat Chimera Courtesy of Dr. Gary B. Anderson -University of California, Davis Now, researchers are developing human-animal chimeras to study disease processes, test new drugs, and develop organs for future transplant patients. The chimeras are produced by introducing human stem cells into developing animal embryos. The following are some of the major projects utilizing human- animal chimeras underway in the U.S and internationally: Sheep-to-humans organ transplant project: At the University of Nevada at Reno, researchers have added human stem cells to sheep fetuses to create chimeras that they hope will someday serve as a reliable source of organs for liver transplant patients. Some sheep now have livers with up to 80% human cells that produce the compounds normally made by human livers. (The cells are not all in distinct liver lobes but spread throughout the tissue.
    [Show full text]
  • Human-Animal Chimeras for Autologous Organ Transplantation: Technological Advances and Future Perspectives
    576 Review Article Page 1 of 8 Human-animal chimeras for autologous organ transplantation: technological advances and future perspectives Yingfei Lu1, Yu Zhou1,2, Rong Ju2, Jianquan Chen1,2 1Central Laboratory, Translational Medicine Research Center, 2Department of Obstetrics and Gynecology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing 211100, China Contributions: (I) Conception and design: All authors; (II) Administrative support: None; (III) Provision of study materials or patients: None; (IV) Collection and assembly of data: None; (V) Data analysis and interpretation: None; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. Correspondence to: Jianquan Chen. Central Laboratory, Translational Medicine Research Center, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing 211100, China. Email: [email protected]. Abstract: Organ transplantation is the most promising curation for end-stage organ disease. However, the donor organ shortage has become a global problem that has limited the development of organ transplantation. Human-animal chimeras provide the ability to produce human organs in other species using autologous stem cells [e.g., induced pluripotent stem cells (iPSCs) or adult stem cells], which would be patient-specific and immune-matched for transplantation. Due to the potential application prospect of interspecies chimeras in basic and translational research, this technology has attracted much interest. This review focuses primarily on technological advances, including options of donor stem cell types and gene editing in donor cells and host animals, in addition to perspectives on human-animal chimeras in clinical and basic research. Keywords: Autologous stem cells; embryo complementation; gene editing; human-animal chimeras; organ transplantation Submitted Jul 17, 2019.
    [Show full text]
  • Human-Animal Chimeras
    Issue Brief June 2021 | No. IF21F01 Human-Animal Chimeras: Unethical and Unnecessary by Mary Szoch, M.Ed. Key Points n the United States, the ethical considerations regarding Human-animal chimeras are human-animal chimeras and human embryo research are creatures that are part human and part animal. Since 1979, intertwined. Understanding the regulations on human- there has been a restriction, Ianimal chimeras the United States ought to have requires a known as the 14-Day Rule, on developing this type of review of the United States’ policies on human embryo creature past 14 days gestation research, an overview of what human-animal chimeras are, an in vitro. analysis of the purported benefits of human-animal chimera In 2016, after scientists gained the ability to develop an research, and a synopsis of the ethical questions posed by embryo in vitro beyond nine creating these creatures. days, the National Institutes of Health revisited the 14-Day Rule, but under the pro-life Trump administration, the Rule The serious ethical concerns about the creation of human- was kept in place. animal chimeras and the lack of any beneficial scientific After a partnership with China advancements from chimera experiments make it clear that created the first human- primate chimera, the NIH, human-animal chimeras are unethical and unnecessary. under the Biden administration, opted to once again review the 14-Day Rule. Senators recently voted along party lines against banning the creation of human- animal chimeras through legislation. This report can be read online at frc.org/chimeras 801 G. St. NW Washington, D.C.
    [Show full text]
  • Analysis of Homozygous Mutant Chimeric Mice: Deletion Of
    Proc. Natl. Acad. Sci. USA Vol. 90, pp. 2551-2555, March 1993 Genetics Analysis of homozygous mutant chimeric mice: Deletion of the immunoglobulin heavy-chain joining region blocks B-cell development and antibody production (B-cell deficiency/immunoglobulin gene rearrangement/gene targeting/embryonic stem cells) AYA JAKOBOVITS*, GERMAN J. VERGARA, JACQUELINE L. KENNEDY, JOANNA F. HALES, RYAN P. MCGUINNESS, DENISE E. CASENTINI-BOROCZ, DANIEL G. BRENNER, AND GILLIS R. OTTEN Cell Genesys, Inc., 322 Lakeside Drive, Foster City, CA 94404 Communicated by Ronald W. Davis, November 18, 1992 ABSTRACT Using a recently described method for effi- MATERIALS AND METHODS ciently deriving homozygous targeted alleles in embryonic stem cells, we produced chimeric mice whose tissues were derived Targeting-Vector Construction. Plasmid pUC18-JH, con- partially from embryonic stem cells bearing homozygous de- taining a 6.1-kb EcoRI genomic fragment of the mouse Ig letion of the mouse immunoglobulin heavy-chain joining (JH) heavy-chain (Igh) locus (8), was digested with Xho I and Nae region. Characterization of these chimeric mice indicated that I to delete the 2296-bp fragment containing the entire JH of development at region and the DQ52 gene segment, which was replaced by a homozygous JH deletion leads to arrest B-cell 1150-bp Xho I-BamHI fragment of pMClNeopolA (9, 10) to an early stage, resulting in a total lack ofperipheral B cells and form the targeting vector pmHAJ. The unique pUC-derived serum IgM. These results were confirmed in mice containing Nde I site was used for linearization. the homozygous JH deletion in their germ line.
    [Show full text]