This means that these cells have the ability to develop or "differentiate" into all the major cell and tissue types of the human body. On the other hand, stem cells that are derived from human embryos (which can also be engineered in the lab) or cells that are genetically engineered to revert to a stem-cell-like state are considered to be " pluripotent," according to the Boston Children's Hospital. Stem cells derived from adult organs and tissues are somewhat limited in the types of cells that they can form. Human-animal chimeras are also produced by introducing human stem cells into animals during various developmental stages, be it embryonic, fetal or postnatal (after birth), according to a 2007 article, also published in the journal Cell Stem Cell.Īccording to the National Institutes of Health (NIH), two unique properties make stem cells useful in research: the ability to replicate and restore their populations without much limitation and the ability to form many different cell and tissue types during early development. Human cells and tissues can be grafted into embryos, fetuses or adult vertebrate animals, Behringer said. This can be done through a variety of techniques. Human-animal chimeras are a further example of an interspecies chimera, generated when human cells are introduced into animals. The areas of the geep body that contained sheep cells and DNA were wooly, whereas the areas with goat cells and DNA were hairy. For instance, 1984 marked the development of the first goat and sheep chimera, called the "geep," according to the University of Wisconsin-Madison. Various interspecies chimeras have also been created.
This helps researchers to fully understand the function and relevance of that particular gene within a live model organism.
Chimera animals series#
These animals contain two types of mouse cells that express different genes: one where all the mouse genes are intact, and the other where one copy of a particular gene is deleted, or "knocked out." A series of mating steps using such chimeric mice ultimately results in some offspring in which the gene of interest is completely knocked out in all cells, according to a Scitable (opens in new tab) article published by Nature Education. These cells can be somatic cells - any cell in the body except for reproductive cells - or they may be incorporated into germline tissues, where specialized reproductive cells, or gametes (opens in new tab), such as sperm and egg cells, are produced, according to Behringer.Įxamples of such research tools include chimeric mice, which are bred for use in genetic research. When the cells of different parent organisms come together to form a chimera, they can incorporate into multiple parts of the chimera's body. Most often, however, chimeras are created in a laboratory for research purposes. Behringer, a professor of genetics at the University of Texas MD Anderson Cancer Center in Houston, Texas, published in the journal Cell Stem Cell. Following the transplant, the recipient acquires two genetically distinct tissue and cell types, according to a 2007 review article by Richard R. For instance, tissue chimeras result from organ transplants or tissue transplants (such as a bone marrow transplant). Some examples of chimeras are already familiar to most people. Thus, a chimera is made up of populations of cells that are genetically identical to each of its parent organisms. Instead of a mixture of genes from each parent organism, a given cell contains the genetic information of only one parent organism. The defining feature of a chimera is that the individual cells in its body are not all the same they are genetically distinct. These "parent" organisms may be of the same or different species. A chimera is made of cells that are derived from two (or sometimes more) organisms. In scientific terms, the word "chimera" retains the essence of its mythical roots.
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