Adipose stem cells*
Stem cells derived from fat cells
Adult SC/tissue
A relatively rare undifferentiated cell found in many organs and differentiated tissues with a limited capacity for both self renewal (in the laboratory) and differentiation. Such cells vary in their differentiation capacity, but it is usually limited to cell types in the organ of origin.
The different DNA sequences within a gene locus are termed alleles
Allelic heterogeneity
A single disorder, trait, or pattern of traits caused by different mutations within a gene (
Allogeneic transplant
A transplant in which a patient receives stem cells from someone other than themselves or their identical twin. The patient’s brother, sister, parent may be used as the donor. An unrelated person may also be used as the donor.
Altered nuclear transfer
Process that uses nuclear transfer to create cells that are incapable of forming a normal embryo but can generate stem cells
Amniotic fluid
Liquid from the amniotic sac of a pregnant woman. The amniotic sac surrounds the fetus, protecting and nourishing it. This fluid contains stem cells.
Anti-Rejection Drugs
Daily medications taken by organ transplant patients to prevent organ rejection, by helping to suppress the immune system's response to a new organ
A natural process of self-destruction in certain cells that is determined by the genes and can be initiated by a stimulus or by removal of a repressor agent.
Autologous transplant
A transplant in which a patient receives his or her own stem cells that have been removed or stored
Blastocyst (blastula)
A preimplantation embryo of about 150 cells produced by cell division following fertilization. The blastocyst is a sphere made up of an outer layer of cells (the trophoblast), a fluid-filled cavity (the blastocoel), and a cluster of cells on the interior (the inner cell mass).
Cellular differentiation
The process in which a stem cell becomes a specialized cell
An organism composed of cells or tissues from more than one individual or species (The National Academies)
The epithelial cells (the cells that line the surface of a cavity) of the bile duct
Chromatin Packaging
The packaging of DNA into chromatin allows the DNA of human cells (about 2 m in length if stretched out) to fit into a nucleus with a diameter of only 10 microns
A structure consisting of DNA and regulatory proteins found in the nucleus of the cell. The DNA in the nucleus is usually divided up among several chromosomes.The number of chromosomes in the nucleus varies depending on the species of the organism. Humans have 46 chromosomes.
To generate identical copies of a region of a DNA molecule or to generate genetically identical copies of a cell, or organism; (n) The identical molecule, cell, or organism that results from the cloning process.1.In reference to DNA: To clone a gene, one finds the region where the gene resides on the DNA and copies that section of the DNA using laboratory techniques.
2.In reference to cells grown in a tissue culture dish:a clone is a line of cells that is genetically identical to the originating cell. This cloned line is produced by cell division (mitosis) of the original cell.
3.In reference to organisms: Many natural clones are produced by plants and (mostly invertebrate) animals. The term clone may also be used to refer to an animal produced by somatic cell nuclear transfer (SCNT) or parthenogenesis.
Cumulus cell
Specialized cells surrounding and nourishing the oocyte (
Cluster of Differentiation or CD is a system to classify cell surface molecules on a variety of cell types. These cell surface molecules are generally proteins or glycoprotiens and often serve as receptors or ligands (the molecule that activates a receptor). As of 2011, there are about 250 numbered CD for human cells.
Cumulus Matrix
The extracellular matrix of the cumulus cell
An immunosuppressant drug widely used in post-allogeneic organ transplant to reduce the activity of the patient's immune system, and therefore the risk of organ rejection
Any of a group of fungal metabolites that interfere with the formation of microfilaments and thus disrupt cellular processes dependent on those filaments (
Cytoplasmic Hybrid
A eukaryotic cell line produced by the fusion of a whole cell with a cytoplast (an enucleated cell)
The process in which a specialized cell regresses into a simpler, less specialized cell. A specialized cell can regress into an embryonic-like cell
Dermal Fibroblasts
Fibroblasts (see below) of the dermis, the layer of skin between the epidermis and subcutaneous tissues.
The process whereby an unspecialized embryonic cell acquires the features of a specialized cell such as a heart, liver, or muscle cell. Differentiation is controlled by the interaction of a cell's genes with the physical and chemical conditions outside the cell, usually through signaling pathways involving proteins embedded in the cell surface.
A complete set of chromosomes with both members of each chromosome pair. Human somatic cells are diploid.
Directed Differentiation
Manipulating stem cell culture conditions to induce differentiation into a particular cell type
DNA Methylation
The addition of a methyl group to DNA — for example, to the number 5 carbon of the cytosine pyrimidine ring — with the specific effect of reducing gene expression. It also forms the basis of chromatin structure, which enables cells to form the myriad characteristics necessary for multicellular life from a single immutable sequence of DNA
DNA Modification
A variety of chemical changes made to a DNA molecule just after it has been replicated. An example is DNA methylation

The production of an embryo
Embryoid bodies
Rounded collections of cells that arise when embryonic stem cells are cultured in suspension. Embryoid bodies contain cell types derived from all 3 germ layers.
Embryonic stem cells
Stem cells taken from the embryo

Without a nucleus
The tissue type derived from the inner mass of the blastocyte
Having to do with the process by which regulatory proteins can turn genes on or off in a way that can be passed on during cell division. ({3C35BAB6-0FE6-4C4E-95F2-2CB61B58D96D}&NRORIGINALURL=%2finfo%2fglossary.asp&NRCACHEHINT=NoModifyGuest#oligodendrocyte)
A site on an antigen that is recognized by an antibody; epitopes are also called antigenic determinants (
Excess IVF embryos
The surplus of embryos that an IVF clinic has, which can later be used for research
A fibroblast is the most common type of cell found in connective tissue. Fibroblasts secrete collagen proteins that are used to maintain a structural framework for many tissues. They also play an important role in healing wounds. (
Fluorescence-activated cell sorting (FACS)*
A flow cytometer (a scientific instrument used to measure the characteristics of individual cells) that is modified for the purpose of separating (sorting) cells based on the amount of light (fluorescence) emitted by each cell. (
An egg (in the female) or sperm (in the male) cell.
The breaking apart of cells or cell organelles into smaller parts
A functional unit of heredity that is a segment of DNA found on chromosomes in the nucleus of a cell. Genes direct the formation of an enzyme or other protein.
The process of forming the 3 germ layers (endoderm, mesoderm, ectoderm) that occurs when a blastula develops into a gastrula
Genome-Wide Approach
An approach that involves rapidly scanning markers across the complete sets of DNA, or genomes, of many people to find genetic variations associated with a particular disease
Germinal cells
Cells in the fetus that give rise to sperm and egg
The line of germ cells that have genetic material that may be passed to a child.
Geron Corporation
A biotechnology company that specializes in developing and commercialization ofcell-based therapies derived from human embryonic stem cells for treatment of various chronic diseases
Global Demethylation
The process of genome-wide removal of methyl groups from nucleotide in DNA
Graft vs. Host Disease
A common complication of allogeneic bone marrow transplantation in which functional immune cells in the transplanted marrow recognize the recipient as "foreign" and mount an immunologic attack. It can also take place in a blood transfusion under certain circumstances
A set of chromosomes with one member of each chromosome pair. Human gametes are haploid.
Hematopoietic stem cells
A stem cell that gives rise to all types of blood cells
Hayflick Limit
The number of times a normal cell population will divide before it stops, presumably because the telomeres reach a critical length. Presumed to be ~50 times.
Hemimethylated DNA
Duplex DNA where only one of the two strands are methylated. It is important for regulating and protecting DNA.
A liver cell
A cell having two or more genetically different nuclei. (
High Telomerase Activity
The enzyme telomerase allows for replacement of short bits of DNA known as telomeres, which are otherwise shortened when a cell divides via mitosis. High activity can lead to cell immortality as well as unbounded growth.
The quality of being accepted and remaining functional; said of that relationship between the genotypes of donor and host in which a graft generally will not be rejected (
Highly alkaline proteins found in eukaryotic cell nuclei, which package and order the DNA into structural units called nucleosomes.
HLA (human leukocyte antigens)
Histocompatibility antigens found on white blood cells that serve as recognition signals to the body’s immune system that enable it to distinguish between innate and foreign material
Homologous genetic recombination
The exchange of a segment of DNA between two homologous chromosomes during meiosis leading to a novel combination of genetic material in the offspring. (
Human embryology
The study of the development of the human embryo
Human Embryonic Stem Cell (hESC) Lines-
Embryonic stem cells, which have been cultured under in vitro conditions that allow proliferation without differentiation for months to years.
Human Telomerase Reverse Transcriptase
A catalytic subunit of the enzyme telomerase.
A cell that is produced in the laboratory from the fusion of an antibody-producing lymphocyte and a nonantibody-producing cancer cell, usually a myeloma or lymphoma. It proliferates and produces a continuous supply of a specific monoclonal antibody. (
A purine base formed as an intermediate in the degradation of purines and purine nucleosides to uric acid and in the salvage of free purines. Complexed with ribose it is inosine.(
In situ
Examining something in the exact place where it occurs
In vitro
Refers to an experiment done in a Petri dish or a test tube
In vivo
Experiments performed in a living organism
Inner Cell Mass
The cluster of cells inside the blastocyst. These cells give rise to the embryo and ultimately the fetus. The inner cell mass cells are used to generate embryonic stem cells
Insertional Mutagenesis
Mutagenesis of DNA by the insertion of one or more bases.
A lipid-soluble molecule usually synthesized by microorganisms to transport ions across the lipid bilayer of the cell membrane
A type of pluripotent stem cell, similar to an embryonic stem cell, formed by the introduction of certain embryonic genes into a somatic cell. ({3C35BAB6-0FE6-4C4E-95F2-2CB61B58D96D}&NRORIGINALURL=%2finfo%2fglossary.asp&NRCACHEHINT=NoModifyGuest#embryo)
Lineage reprogramming*

The location of a gene on a chromosome region is called a locus
Mammary Epithelial Cells
Epithelial cells are cells that cover the surface of the body and line its cavities. Mammary epithelial cells are those located in the breast.
The type of cell division a diploid germ cell undergoes to produce gametes (sperm or eggs) that will carry half the normal chromosome number. This is to ensure that when fertilization occurs, the fertilized egg will carry the normal number of chromosomes rather than causing aneuploidy (an abnormal number of chromosomes).
Mesenchymal stem cells
A term that is currently used to define non-blood adult stem cells from a variety of tissues, although it is not clear that mesenchymal stem cells from different tissues are the same. ({3C35BAB6-0FE6-4C4E-95F2-2CB61B58D96D}&NRORIGINALURL=%2finfo%2fglossary.asp&NRCACHEHINT=NoModifyGuest#oligodendrocyte)
Blood vessel derived stem cell

A type of transferase enzyme that transfers a methyl group from a donor to an acceptor. Involved in DNA methylation
The type of cell division that allows a population of cells to increase its numbers or to maintain its numbers. The number of chromosomes remains the same in this type of cell division.
Monoclonal antibody
Any of a class of highly specific antibodies produced by the clones of a single hybrid cell formed in the laboratory by the fusion of a B cell with a tumor cell and widely used in medical and biological research. (
A type of white blood cell that replenishes macrophages and dentritic cells
The cells in the zygote divide to form a compact ball of cells called the morula
Multipotent stem cells
Cells that can differentiate into a more limited number of unique cells. For example, a hematopoietic cell is amultipotent blood stem cell type that can develop into several types of blood cells, but cannot develop into brain cells or other types of cells. However, it is being discovered that their plasticity is greater that originally thought.
Myeloma cells
A tumor composed of cells of the type normally found in the bone marrow (
Of or relating to newborn infants or an infant
The process of generating neurons
Nuclear transfer
Technique in which nuclear genetic material from a patient’s own cell is isolated and then transferred into an enucleated oocytes
Octamer Transcription Factor
A transcription factor which binds to the "ATTTGCAT" sequence.
One of the cells forming the outer surface of dental pulp that produces the dentin of a tooth
A cell that supports nerve cells by creating a myelin sheath around axons
Oligopotent stem cells
Oligopotent stem cells can differentiate into a few cell types. Ex., lymphoid or myeloid stem cells.
A mutated form of a normal cellular gene. Can lead to the production of a cancer cell. (
Developing (immature) egg cell
Ovarian Hyperstimulation
A complication occasionally seen in women who take certain fertility medicines that stimulate egg production
A form of reproduction in which the ovum develops into a new individual without any fertilization or genetic contribution from a male
A portmanteau of farming and "pharmaceutical" and refers to the use of genetic engineering to insert genes that code for useful pharmaceuticals into host animals or plants that would otherwise not express those genes. As a consequence, the host animals or plants then make the pharmaceutical product in large quantity, which can then be purified and used as a drug product.
Pluripotent stem cells
Cells that can differentiate into any other cell type ( i.e., into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system). However, they cannot be implanted into a uterus to create a fetus. Puripotent stem cells can give rise to any fetal or adult cell type, but alone cannot develop into a fetal or adult animal; they lack the potential to give rise to extraembryonic tissue, specifically the placenta.
Pluripotent stem cells (through iPS)
A stem cell that was made by inducing certain embryonic genes into a donated somatic cell that can differentiate into any other cell type but cannot be implanted into a uterus to create a fetus
Point mutation
A type of mutation in which one nucleotide replaces another nucleotide at one point on the DNA sequence
Polar body
A small cell (which eventually disintegrates) that is the by-product of meiosis in female animals. One functional ovum and potentially three polar bodies result from meiosis of each primary oocyte (
Polyclonal antibody
A mixture of immunoglobulin molecules secreted against a specific antigen, each recognizing a different epitope. (
Polycomb Group Repressive Complexes
Polycomb-group proteins are a family of proteins first discovered in fruit flies that can remodel chromatin such that epigenetic silencing of genes takes place
Post Translational Modification
The chemical modification of a protein after its translation
Pre embryo

With regard to an embryo, preimplantation means that the embryo has not yet implanted in the wall of the uterus.
Primitive Streak
The embryonic structure that will establish bilateral symmetry, determine the site of gastrulation and initiate germ layer formation
Progenitor Cells
Like stem cells, progenitor cells have a tendency to differentiate into a specific type of cell. In contrast to stem cells, however, they are already far more specific: they are pushed to differentiate into their "target" cell. The most important difference between stem cells and progenitor cells is that stem cells can replicate indefinitely, whereas progenitor cells can only divide a limited number of times
Promoter DNA Methylation
Methylation of GATC sites in the promoter region
Promoter Region
A region of DNA that facilitates the transcription of a particular gene. Promoters are typically located near the genes they regulate, on the same strand and upstream
The nucleus of a sperm or an egg cell during the process of fertilization, after the sperm enters the ovum, but before they fuse
A nitrogen-containing, double-ring, basic compound that occurs in nucleic acids. The purines in DNA and RNA are adenine and guanine. (
Purkinje Cells
Any of numerous neurons of the cerebral cortex having large flask-shaped cell bodies with massive dendrites and one slender axon
Regenerative Medicine
The use of biological agents, for example stem cells, to treat diseases and repair damaged or destroyed cell populations or tissues.
Silent mutation
A point mutation that has no effect at all on the protein being coded for. Silent mutations do not significantly affect protein function because they do not dramatically change the three dimensional structure of the protein.
Somatic cell hybridization*

Somatic Cell Nuclear Transfer (SCNT)
A technique that combines an enucleated egg and the nucleus of a somatic cell to make an embryo. ({3C35BAB6-0FE6-4C4E-95F2-2CB61B58D96D}&NRORIGINALURL=%2finfo%2fglossary.asp&NRCACHEHINT=NoModifyGuest#oligodendrocyte)
Stem cell
Primitive self-renewing cells that can develop into functional differentiated cells
Stochastic Event
A random event, exhibiting non-deterministic behavior
Syngeneic transplant
A transplant in which a patient receives stem cells from his or her identical twin
A region of repetitive DNA at the end of a chromosome, which protects the end of the chromosome from deterioration
A gonadal tumor
A multi-layered benign tumor that grows from pluripotent cells injected into mice with a dysfunctional immune system. Scientists test whether they have established a human embryonic stem cell (hESC) line by injecting putative stem cells into such mice and verifying that the resulting teratomas contain cells derived from all three embryonic germ layers ({3C35BAB6-0FE6-4C4E-95F2-2CB61B58D96D}&NRORIGINALURL=%2finfo%2fglossary.asp&NRCACHEHINT=NoModifyGuest#teratoma)
In medical context, grows in reproductive tract as benign tumor of ovary, testis (?); tumor can contains random clusters of mixed cell types (e.g., teeth, hair, organ tissue etc.)
Tissue Plasminogen Activator
a protein involved in the breakdown of blood clots
Totipotent stem cells
Cells that can differentiate into any specialized cell and have the potential to develop into a complete fetus and a placenta.
Transcriptional Start Site
The location on the DNA, usually after the promoter, where transcription into mRNA begins.
The process in which a non-stem cell differentiates into another type of specialized cell.
Infection of a bacterium or cell with DNA or RNA isolated from a bacteriophage or from an animal or a plant virus, resulting in replication of the complete virus.
Translocation is a type of chromosomal abnormality in which a chromosome breaks and a portion of it reattaches to a different chromosome. Chromosomal translocations can be detected by analyzing karyotypes of the affected cells. (
Unipotent cells
A unipotent cell technically is a progenitor or precursor cell, not a stem cell. Its self renewal in vivo and in vitro is limited. Like oligopotent cells it has only the capacity to develop/differentiate into only one type of tissue/cell type. Ex. Adult skin cells and liver cells (the liver's ability to regenerate from as little as 25% of its original mass is attributed to this property).
Zona Pellucida
A glycoprotein membrane surrounding the plasma membrane of an oocyte
The resulting formation when an ovum is fertilized by a sperm