Stem Cell Cloning Glossary
Adult Stem Cell: A stem cell from organs and tissues after
birth (including umbilical cord and placenta) that can renew itself
and transform into other specialized cell types.
Assisted reproductive technology: Fertility treatments
that involve a laboratory handling eggs or embryos, such as in vitro
fertilization.
Blastocyst: A pre-implantation embryo, approximately 5-7
days after conception (30-150 cells).
Cloning: The creation of an animal or person that derives
its genes from a single other individual; “asexual reproduction”.
Creating a copy that is virtually (but not exactly) identical to the
original. It can be done with molecules, cells, and whole organisms.
Chromosomes: The structures that contain the genes.
Normal human cells contain 46 chromosomes; mature normal human
gametes have 23 chromosomes.
Differentiation: The process by which early unspecified
cells acquire the features of specific cells such as heart, liver,
muscle, or brain tissue.
DNA: Abbreviation for deoxyribonucleic acid. The genetic
material that contains the instructions for making an entire
organism.
Embryo: The earliest stage of human development, from the
single cell up to about 8 weeks.
Both sexual reproduction (egg+sperm) and asexual reproduction
(cloning, i.e., somatic cell nuclear transfer) produce a human
embryo, a living human organism which is a member of the species
Homo sapiens. The cloning process, and the cloned embryo produced,
are identical in both “reproductive” (live birth) cloning and
“therapeutic” (experimental) cloning. The only difference is the
use of the cloned embryo (implantation for live birth or destruction
for harvest of stem cells or tissues).
Embryonic stem cell: A cell from the inner group of cells
of a blastocyst, with the potential to become most or all of the
body tissues.
Gamete: A mature germ cell (egg or sperm), which unites
with another in sexual reproduction.
Gene: A unit of heredity that is a segment of DNA located
on a specific site on a chromosome.
Germ cell: Egg or sperm.
In vitro: Done outside of the body.
In vivo: Done within the living body.
Multipotent: Capable of giving rise to several specialized
cells or tissues of an organism.
Nucleus: The core of a cell that contains the chromosomes
(genetic material).
Pluripotent: Capable of giving rise to most tissues of the
adult body.
“Reproductive Cloning”: Although this term is often used
to indicate live-born cloning, all human cloning (including
“therapeutic cloning”) is reproductive in that it creates -
reproduces - a new developing human intended to be virtually
identical to the cloned subject. The term “reproductive cloning” has
been used to signify the implantation into a womb of a cloned
embryo, in hopes of a live birth.
Somatic cell: Cell of the body other than a gamete (other
than an egg or sperm).
Somatic cell nuclear transfer: The transfer of a cell
nucleus from a body cell into an egg from which the chromosomes have
been removed or inactivated; the method used for cloning of an
organism. Once the transferred genome is within the egg cell and a
one-cell embryo is created, the process of cloning is complete and
further development of the clone can occur.
Stem cells: Non-specialized cells that have the capacity
to self-renew and to transform into other mature cell and tissue
types.
“Therapeutic Cloning” (Experimental Cloning): Creating a
cloned human embryo for experimental purposes, including destroying
it to harvest embryonic stem cells or tissues.
Tissue or cell culture: Growth of cells or tissues in a
laboratory dish for experimental research.
Totipotent: Capable of giving rise to all tissues and
organs, including placenta.
Zygote: A one-cell embryo. Even at this stage the embryo
is a human being (species Homo sapiens).
Prepared by David A. Prentice, Ph.D.
Professor, Life Sciences, Indiana State University
Adjunct Professor, Medical & Molecular Genetic
Indiana University School of Medicine
Websites:
http://www.stemcellresearch.org
Do No Harm: The Coalition of Americans for Research Ethics
http://www.cloninginformation.org
Cloning Information |
