Human cloning is the creation of a genetically identical copy of a human. The term is generally used to refer to artificial human cloning, which is the reproduction of human cells and tissue. It does not refer to the natural conception and delivery of identical twins. The possibilities of human cloning have raised controversies. These ethical concerns have prompted several nations to pass laws regarding human cloning.
In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell in a cell lineage. They are found in both embryonic and adult organisms, but they have slightly different properties in each. They are usually distinguished from progenitor cells, which cannot divide indefinitely, and precursor or blast cells, which are usually committed to differentiating into one cell type.
In genetics and developmental biology, somatic cell nuclear transfer (SCNT) is a laboratory strategy for creating a viable embryo from a body cell and an egg cell. The technique consists of taking a denucleated oocyte and implanting a donor nucleus from a somatic (body) cell. It is used in both therapeutic and reproductive cloning. In 1996, Dolly the sheep became famous for being the first successful case of the reproductive cloning of a mammal. In January 2018, a team of scientists in Shanghai announced the successful cloning of two female crab-eating macaques from foetal nuclei.
Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood, in order to replicate inside a patient and produce additional normal blood cells. HSCT may be autologous, syngeneic, or allogeneic.
Embryonic stem cells (ESCs) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage pre-implantation embryo. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells. Isolating the inner cell mass (embryoblast) using immunosurgery results in destruction of the blastocyst, a process which raises ethical issues, including whether or not embryos at the pre-implantation stage have the same moral considerations as embryos in the post-implantation stage of development.
Adult stem cells are undifferentiated cells, found throughout the body after development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Also known as somatic stem cells, they can be found in juvenile, adult animals, and humans, unlike embryonic stem cells.
Proposition 71 of 2004 is a law enacted by California voters to support stem cell research in the state. It was proposed by means of the initiative process and approved in the 2004 state elections on November 2. The Act amended both the Constitution of California and the Health and Safety Code.
The stem cell controversy concerns the ethics of research involving the development and use of human embryos. Most commonly, this controversy focuses on embryonic stem cells. Not all stem cell research involves human embryos. For example, adult stem cells, amniotic stem cells, and induced pluripotent stem cells do not involve creating, using, or destroying human embryos, and thus are minimally, if at all, controversial. Many less controversial sources of acquiring stem cells include using cells from the umbilical cord, breast milk, and bone marrow, which are not pluripotent.
Stem-cell therapy uses stem cells to treat or prevent a disease or condition. As of 2024, the only FDA-approved therapy using stem cells is hematopoietic stem cell transplantation. This usually takes the form of a bone marrow or peripheral blood stem cell transplantation, but the cells can also be derived from umbilical cord blood. Research is underway to develop various sources for stem cells as well as to apply stem-cell treatments for neurodegenerative diseases and conditions such as diabetes and heart disease.
A progenitor cell is a biological cell that can differentiate into a specific cell type. Stem cells and progenitor cells have this ability in common. However, stem cells are less specified than progenitor cells. Progenitor cells can only differentiate into their "target" cell type. The most important difference between stem cells and progenitor cells is that stem cells can replicate indefinitely, whereas progenitor cells can divide only a limited number of times. Controversy about the exact definition remains and the concept is still evolving.
Stem cell research policy varies significantly throughout the world. There are overlapping jurisdictions of international organizations, nations, and states or provinces. Some government policies determine what is allowed versus prohibited, whereas others outline what research can be publicly financed. Of course, all practices not prohibited are implicitly permitted. Some organizations have issued recommended guidelines for how stem cell research is to be conducted.
Elaine V. Fuchs is an American cell biologist known for her work on the biology and molecular mechanisms of mammalian skin and skin diseases, who helped lead the modernization of dermatology. Fuchs pioneered reverse genetics approaches, which assess protein function first and then assess its role in development and disease. In particular, Fuchs researches skin stem cells and their production of hair and skin. She is an investigator at the Howard Hughes Medical Institute and the Rebecca C. Lancefield Professor of Mammalian Cell Biology and Development at The Rockefeller University.
Stem Cell Research Enhancement Act was the name of two similar bills that both passed through the United States House of Representatives and Senate, but were both vetoed by President George W. Bush and were not enacted into law.
Induced pluripotent stem cells are a type of pluripotent stem cell that can be generated directly from a somatic cell. The iPSC technology was pioneered by Shinya Yamanaka and Kazutoshi Takahashi in Kyoto, Japan, who together showed in 2006 that the introduction of four specific genes, collectively known as Yamanaka factors, encoding transcription factors could convert somatic cells into pluripotent stem cells. Shinya Yamanaka was awarded the 2012 Nobel Prize along with Sir John Gurdon "for the discovery that mature cells can be reprogrammed to become pluripotent."
Stem cell laws are the law rules, and policy governance concerning the sources, research, and uses in treatment of stem cells in humans. These laws have been the source of much controversy and vary significantly by country. In the European Union, stem cell research using the human embryo is permitted in Sweden, Spain, Finland, Belgium, Greece, Britain, Denmark and the Netherlands; however, it is illegal in Germany, Austria, Ireland, Italy, and Portugal. The issue has similarly divided the United States, with several states enforcing a complete ban and others giving support. Elsewhere, Japan, India, Iran, Israel, South Korea, China, and Australia are supportive. However, New Zealand, most of Africa, and most of South America are restrictive.
Stem cell laws and policy in the United States have had a complicated legal and political history.
The Cambridge Stem Cell Institute at the University of Cambridge is a research centre for the nature and potential medical uses of stem cells. It is located on the Cambridge Biomedical Campus in Cambridge, England and was originally funded by the Wellcome Trust and the Medical Research Council.
Cell potency is a cell's ability to differentiate into other cell types. The more cell types a cell can differentiate into, the greater its potency. Potency is also described as the gene activation potential within a cell, which like a continuum, begins with totipotency to designate a cell with the most differentiation potential, pluripotency, multipotency, oligopotency, and finally unipotency.
Mesenchymal stem cells (MSCs) also known as mesenchymal stromal cells or medicinal signaling cells, are multipotent stromal cells that can differentiate into a variety of cell types, including osteoblasts, chondrocytes, myocytes and adipocytes.
Patricia Helena Lucas Pranke is a Brazilian stem cell researcher at the Federal University of Rio Grande do Sul. Between 2003 and 2005, Pranke was one of two scientists who helped the Federal Government of Brazil write the National Biosafety Law, regulating research on human embryonic stem cells in Brazil.
