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Trisomy 21 (Down Syndrome)
As of 2022, Trisomy 21 is the most common type of trisomy, or a condition where the person has three instead of the normal two copies of one of the chromosomes. Trisomy occurs when abnormal cell division takes place leading to an extra copy of a chromosome. That extra copy of chromosome 21 results in a congenital disorder called Down syndrome, which is characterized by a cluster of specific traits including intellectual disabilities, atypical facial appearance, and a high risk of heart disease.
Format: Articles
Subject: Reproduction, Disorders, Ethics
Jérôme Lejeune (1926−1994)
Jérôme Lejeune was a French physician and researcher who studied genetics and developmental disorders. According to the Jérôme Lejeune Foundation, in 1958, Lejeune discovered that the existence of an extra twenty-first chromosome, a condition called Trisomy 21, causes Down Syndrome. Down Syndrome is a condition present in an individual since birth and is characterized by physical and developmental anomalies such as small ears, a short neck, heart defects, and short height as children and adults.
Format: Articles
Subject: People
Theophilus Shickel Painter (1889-1969)
Theophilus Shickel Painter studied the structure and
function of chromosomes in the US during in the early to mid-twentieth century. Painter worked at
the University of Texas at Austin in Austin, Texas. In the 1920s
and 1930s, Painter studied the chromosomes of the salivary gland
giant chromosomes of the fruit fly (Drosophila
melanogaster), with Hermann J. Muller. Muller and Painter
studied the ability of X-rays to cause changes in the chromosomes
of fruit flies. Painter also studied chromosomes in mammals.
Format: Articles
Subject: People
Kurt Benirschke (1924-)
Kurt Benirschke studied cells, placentas, and endangered species in Germany and the US during the twentieth century. Benirschke was professor at the University of California in San Diego, California, and a director of the research department at the San Diego Zoo in San Diego, California. He also helped form the research department of the San Diego Zoo and its sister organization, the Center for Reproduction of Endangered Species.
Format: Articles
Subject: People
"Derivation of Pluripotent Stem Cells from Cultured Human Primordial Germ Cells" (1998), by John Gearhart et al.
In November 1998, two independent reports were published concerning the first isolation of pluripotent human stem cells, one of which was "Derivation of Pluripotent Stem Cells from Cultured Human Primordial Germ Cells." This paper, authored by John D. Gearhart and his research team - Michael J Shamblott, Joyce Axelman, Shunping Wang, Elizabeith M. Bugg, John W. Littlefield, Peter J. Donovan, Paul D. Blumenthal, and George R. Huggins - was published in Proceedings of the National Academy of Science soon after James A.
Format: Articles
Subject: Publications
Amniocentesis
Amniocentesis is a test used for prenatal diagnosis of inherited diseases, Rh incompatibility, neural tube defects, and lung maturity. Normally performed during the second trimester of a pregnancy, this invasive procedure allows the detection of health problems in the fetus as early as fifteen weeks gestation. Although amniocentesis does carry some significant risks, the medical community commonly accepts it as a safe and useful procedure.
Format: Articles
Subject: Technologies, Reproduction
"Formation of Genetically Mosaic Mouse Embryos and Early Development of Lethal (t12/t12)-Normal Mosaics" (1964), by Beatrice Mintz
The paper "Formation of Genetically Mosaic Mouse Embryos and Early Development of Lethal (t12/t12)-Normal Mosaics," by Beatrice Mintz, describes a technique to fuse two mouse embryos into a single embryo. This work was published in the Journal of Experimental Zoology in 1964. When two embryos are correctly joined before the 32-cell stage, the embryo will develop normally and exhibit a mosaic pattern of cells as an adult.
Format: Articles
Subject: Experiments
Chorionic Villus Sampling
Chorionic villus sampling (CVS) is a test used for prenatal diagnosis. Safe to perform at an earlier stage in pregnancy than amniocentesis, CVS is another invasive prenatal diagnostic test that can be performed as early as ten weeks after the woman's last menstrual cycle. While this test does carry some risks, it is generally very effective at predicting heritable diseases during or soon after the embryonic stage of development.
Format: Articles
Subject: Technologies
Human Embryonic Stem Cells
Stem cells are undifferentiated cells that are capable of dividing for long periods of time and can give rise to specialized cells under particular conditions. Embryonic stem cells are a particular type of stem cell derived from embryos. According to US National Institutes of Health (NIH), in humans, the term "embryo" applies to a fertilized egg from the beginning of division up to the end of the eighth week of gestation, when the embryo becomes a fetus. Between fertilization and the eighth week of gestation, the embryo undergoes multiple cell divisions.
Format: Articles
Subject: Processes, Reproduction
Amniocentesis Prior to 1980
The extraembryonic membranes that surround and originate from the embryos of vertebrates such as birds, reptiles, and mammals are crucial to their development. They are integral to increasing the surface area of the uterus, forming the chorion (which in turn produces the placenta) and the amnion, respectively. The amnion will ultimately surround the embryo in a fluid-filled amniotic cavity. This amniotic fluid, which cushions and protects the fetus and helps prevent the onset of labor, is sampled in amniocentesis to screen for genetic diseases.
Format: Articles
Subject: Processes, Reproduction
"Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells" (2007), by Junying Yu et al.
On 2 December 2007, Science published a report on creating human induced pluripotent stem (iPS) cells from human somatic cells: "Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells." This report came from a team of Madison, Wisconsin scientists: Junying Yu, Maxim A. Vodyanik, Kim Smuga-Otto, Jessica Antosiewicz-Bourget, Jennifer L. Frane, Shulan Tian, Jeff Nie, Gudrun A. Jonsdottir, Victor Ruotti, Ron Stewart, Igor I. Slukvin, and James A. Thomson.
Format: Articles
Subject: Publications
Anencephaly
Anencephaly is an open neural tube defect, meaning that part of the neural tube does not properly close or that it has reopened during early embryogenesis. An embryo with anencephaly develops without the top of the skull, but retains a partial skull, including the face. Anencephaly is one of the most common birth defects of the neural tube, occurring at a rate of approximately one in one thousand human pregnancies. The condition can be caused by environmental exposure to chemicals, dietary deficiencies, or genetic mutations.
Format: Articles
Subject: Disorders, Reproduction
Interspecies SCNT-derived Humanesque Blastocysts
Since the 1950s, scientists have developed interspecies blastocysts in laboratory settings, but not until the 1990s did proposals emerge to engineer interspecies blastocysts that contained human genetic or cellular material. Even if these embryos were not permitted to mature to fetal stages, their ethical and political status became debated within nations attempting to use them for research.
Format: Articles
Subject: Theories