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Telomerase in Human Development
Telomerase is an enzyme that regulates the lengths of telomeres in the cells of many organisms, and in humans it begins to function int the early stages of embryonic development. Telomeres are repetitive sequences of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling. In 1989, Gregg Morin found that telomerase was present in human cells. In 1996, Woodring Wright and his team examined human embryonic cells and found that telomerase was active in them. Scientists manipulate telomerase in cells to give cells the capacity to replicate infinitely.
Format: Articles
Subject: Theories
“Annual Research Review: Prenatal Stress and the Origins of Psychopathology: An Evolutionary Perspective” (2011), by Vivette Glover
In 2011, fetal researcher Vivette Glover published “Annual Research Review: Prenatal Stress and the Origins of Psychopathology: An Evolutionary Perspective,” hereafter, “Prenatal Stress and the Origins of Psychopathology,” in the Journal of Child Psychology and Psychiatry. In that article, Glover explained how an evolutionary perspective may be useful in understanding the effects of fetal programming. Fetal programming is a hypothesis that attempts to explain how factors during pregnancy can affect fetuses after birth.
Format: Articles
Subject: Theories, Reproduction, Disorders
“Does Air Pollution Play a Role in Infertility?: a Systematic Review” (2017), by Julie Carré, Nicolas Gatimel, Jessika Moreau, Jean Parinaud and Roger Léandri
In 2017, Julie Carré, Nicolas Gatimel, Jessika Moreau, Jean Parinaud, and Roger Léandri published “Does Air Pollution Play a Role in Infertility?: a Systematic Review,” hereafter “Does Air Pollution Play a Role,” in the journal Environmental Health. The authors completed a systematic literature review to investigate the effects of air pollutants on fertility in exposed populations.
Format: Articles
Subject: Publications, Reproduction
“Sources of Human Psychological Differences: The Minnesota Study of Twins Reared Apart” (1990), by Thomas J. Bouchard Jr, David T. Lykken, Matthew McGue, Nancy L. Segal and Auke Tellegen
In 1990, Thomas J. Bouchard and his colleagues published the paper “Sources of Human Psychological Differences: The Minnesota Study of Twins Reared Apart” in Science Magazine. The paper described the results of a study initiated in 1979 on the development of twins raised in different environments. The scientists conducted their experiment at the University of Minnesota, in Minneapolis, Minnesota. The researchers physiologically and psychologically assessed monozygotic twins or triplets who were reared apart, comparing the similarity of those twins to twins who were reared together.
Format: Articles
Subject: Publications
HeLa Cell Line
The HeLa cell line was the first immortal human cell line that George Otto Gey, Margaret Gey, and Mary Kucibek first isolated from Henrietta Lacks and developed at The Johns Hopkins Hospital in Baltimore, Maryland, in 1951. An immortal human cell line is a cluster of cells that continuously multiply on their own outside of the human from which they originated. Scientists use immortal human cell lines in their research to investigate how cells function in humans.
Format: Articles
Subject: Technologies, Experiments, People, Ethics
Oliver Allison Ryder III (1946– )
Oliver Allison Ryder studied chromosomal evolution and endangered species in efforts for wildlife conservation and preservation at the San Diego Zoo in San Diego, California. Throughout his career, Ryder studied breeding patterns of endangered species. He collected and preserved cells, tissues, and DNA from endangered and extinct species to store in the San Diego Frozen Zoo, a center for genetic research and development in San Diego, California.
Format: Articles
Subject: People
The Debate over DNA Replication Before the Meselson-Stahl Experiment (1953–1957)
Between 1953 and 1957, before the Meselson-Stahl experiment verified semi-conservative replication of DNA, scientists debated how DNA replicated. In 1953, James Watson and Francis Crick proposed that DNA was composed of two helical strands that wound together in a coil. Their model suggested a replication mechanism, later termed semi-conservative replication, in which parental DNA strands separated and served as templates for the replication of new daughter strands.
Format: Articles
Subject: Theories
In the Womb (2005), by Toby Mcdonald and National Geographic Channel
Written, produced, and directed by Toby Mcdonald, the 2005 National Geographic Channel film In the Womb uses the most recent technology to provide an intricate glimpse into the prenatal world. The technologies used, which include advanced photography, computer graphics, and 4-D ultrasound imaging, help to realistically illustrate the process of development and to answer questions about the rarely seen development of a human being.
Format: Articles
Subject: Outreach, Reproduction
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
"On the Replication of Desoxyribonucleic Acid (DNA)" (1954), by Max Delbruck
In 1954 Max Delbruck published On the Replication of Desoxyribonucleic Acid (DNA) to question the semi-conservative DNA replication mechanism proposed that James Watson and Francis Crick had proposed in 1953. In his article published in the Proceedings of the National Academy of Sciences, Delbrück offers an alternative DNA replication mechanism, later called dispersive replication. Unlike other articles before it, On the Replication presents ways to experimentally test different DNA replication theories.
Format: Articles
Subject: Publications
Paternal Sperm Telomere Elongation and Its Impact on Offspring Fitness
Telomeres are structures at the ends of DNA strands that get longer in the DNA of sperm cells as males age. That phenomenon is different for most other types of cells, for which telomeres get shorter as organisms age. In 1992, scientists showed that telomere length (TL) in sperm increases with age in contrast to most cell of most other types. Telomeres are the protective caps at the end of DNA strands that preserve chromosomal integrity and contribute to DNA length and stability.
Format: Articles
Subject: Theories
Isotretinoin (Accutane) as a Teratogen
Isotretinoin is a molecule and a byproduct (metabolite) of vitamin A, and in greater than normal amounts in pregnant women, it can cause fetal abnormalities including cleft lips, ear and eye defects, and mental retardation. Isotretinoin is commonly called by its trade name Accutane, and it's a chemical compound derived from vitamin A, or retinoic acid. Doctors prescribe isotretinoin to treat severe acne. For pregnant women, too much vitamin A or isotretinoin can also cause greater than normal rates of stillbirths and fetal disintegrations after the ninth week of gestation.
Format: Articles
Subject: Reproduction, Disorders
David Wildt's Evolving Ethics Concerning the Roles of Wildlife Reproductive Sciences in Species Conservation
David Wildt is an animal reproductive biologist who directs the Conservation Biology Institute in Fort Royal, Virginia. In 1986, Wildt argued that artificial reproductive technologies should only be used for species conservation efforts if standard techniques to aid natural reproduction are not effective. Between 1986 and 2001, Wildt revised his views and values primarily in relation to two things: which methods captive breeding programs ought to use, and how reproductive scientists ought to contribute to the larger work of conservation.
Format: Articles
Subject: Ethics
Mesoderm
Mesoderm is one of the three germ layers, groups of cells that interact early during the embryonic life of animals and from which organs and tissues form. As organs form, a process called organogenesis, mesoderm interacts with endoderm and ectoderm to give rise to the digestive tract, the heart and skeletal muscles, red blood cells, and the tubules of the kidneys, as well as a type of connective tissue called mesenchyme. All animals that have only one plane of symmetry through the body, called bilateral symmetry, form three germ layers.
Format: Articles
Subject: Processes
Robert Lanza (1956- )
During the twentieth and twenty-first centuries, Robert Paul Lanza studied embryonic stem cells, tissues,
and endangered species as chief scientific officer of Advanced Cell
Technology, Incorporated in Worcester, Massachusetts. Lanza's team cloned
the endangered species of gaur Bos gaurus.
Although the gaur did not survive long, Lanza successfully cloned
another cow-like creature, called the banteng
(Bos
javanicus). Lanza also worked on cloning human embryos
to harvest stem cells, which could be used to treat dieases. While
Format: Articles
Subject: People
Equilibrium Density Gradient Centrifugation in Cesium Chloride Solutions Developed by Matthew Meselson and Franklin Stahl
Matthew Meselson, Franklin Stahl, and Jerome Vinograd, developed cesium chloride, or CsCl, density gradient centrifugation in the 1950s at the California Institute of Technology, or Caltech, in Pasadena, California. Density gradient centrifugation enables scientists to separate substances based on size, shape, and density. Meselson and Stahl invented a specific type of density gradient centrifugation, called isopycnic centrifugation that used a solution of cesium chloride to separate DNA molecules based on density alone.
Format: Articles
Subject: Technologies
Sheldon Clark Reed (1910-2003)
Sheldon Clark Reed helped establish the profession of genetic counseling in the US during the twentieth century. In 1947 Reed coined the term genetic counseling to describe the interaction of a doctor explaining to a patient the likelihood of passing a certain trait to their offspring. With physicians being able to test for genetic abnormalities like cystic fibrosis, Reed helped trained individuals give patients the tools to make informed decisions. In 1955 Reed published the book Counseling in Medical Genetics.
Format: Articles
Subject: People
"Control of Corneal Differentiation by Extracellular Materials" (1974), by Stephen Meier and Elizabeth D. Hay
In 1974, Elizabeth Dexter Hay and Stephen Meier in the US conducted an experiment that demonstrated that the extracellular matrix, the mesh-like network of proteins and carbohydrates found outside of cells in the body, interacted with cells and affected their behaviors. In the experiment, Hay and Meier removed the outermost layer of cells that line the front of the eye, called corneal epithelium, from developing chick embryos.
Format: Articles
Subject: Experiments
"The Familial Factor in Toxemia of Pregnancy" (1968), by Leon C. Chesley, et al.
In the 1950s and 1960s, researchers Leon Chesley, John Annitto, and Robert Cosgrove investigated the possible familial factor for the conditions of preeclampsia and eclampsia in pregnant women. Preeclampsia and eclampsia, which are related to high blood pressure, have unknown causes and affect at least five percent of all pregnancies.
Format: Articles
Subject: Reproduction, Experiments, Disorders
The Case Against Perfection: Ethics in the Age of Genetic Engineering (2007), by Michael J. Sandel
The Case against Perfection: Ethics in the Age of Genetic Engineering, hereafter referred to as The Case against Perfection, written by Michael J. Sandel, builds on a short essay featured in The Atlantic Monthly magazine in 2004. Three years later, Sandel transformed his article into a book, keeping the same title but expanding upon his personal critique of genetic engineering. The purpose of Sandel's book is to articulate the sources of what he considers to be widespread public unease related to genetic engineering that changes the course of natural development.
Format: Articles
Subject: Publications, Ethics
Effect of Prenatal Alcohol Exposure on Radial Glial Cells
Prenatal alcohol (ethanol) exposure can have dramatic effects on the development of the central nervous system (CNS), including morphological abnormalities and an overall reduction in white matter of the brain. The impact of ethanol on neural stem cells such as radial glia (RG) has proven to be a significant cause of these defects, interfering with the creation and migration of neurons and glial cells during development.
Format: Articles
Subject: Disorders, Reproduction
Gastrulation in Mus musculus (common house mouse)
As mice embryos develop, they undergo a stage of development called gastrulation. The hallmark of vertebrate gastrulation is the reorganization of the inner cell mass (ICM) into the three germ layers: ectoderm, mesoderm, and endoderm. Mammalian embryogenesis occurs within organisms; therefore, gastrulation was originally described in species with easily observable embryos. For example, the African clawed frog (Xenopus laevis) is the most widely used organism to study gastrulation because the large embryos develop inside a translucent membrane.
Format: Articles
Subject: Processes, Experiments
VACTERL Association
VACTERL association is a term applied to a specific group of abnormalities involving structures derived from the mesoderm. Although the defects of this disorder are clearly linked, VACTERL is called an association rather than a syndrome because the exact genetic cause is unknown. "VACTERL" is an acronym, each letter standing for one of the defects associated with the condition: V for vertebral anomalies, A for anal atresia, C for cardiovascular anomalies, T for tracheoesophageal fistula, E for esophageal atresia, R for renal anomalies, and L for limb defects.
Format: Articles
Subject: Disorders
The Organism as a Whole: From a Physicochemical Viewpoint (1916), by Jacques Loeb
Jacques Loeb published The Organism as a Whole: From a Physicochemical Viewpoint in 1916. Loeb's goal for the book was to refute the claim that physics and chemistry were powerless to completely explain whole organisms and their seemingly goal-oriented component processes. Loeb used his new account of science and scientific explanation, marshaling evidence from his embryological researches, to show that physicochemical biology completely and correctly explained whole organisms and their component processes.
Format: Articles
Subject: Publications
Fate Mapping Techniques
For more than 2000 years, embryologists, biologists, and philosophers have studied and detailed the processes that follow fertilization. The fertilized egg proliferates into cells that begin to separate into distinct, identifiable zones that will eventually become adult structures through the process of morphogenesis. As the cells continue to multiply, patterns form and cells begin to differentiate, and eventually commit to their fate.
Format: Articles
Subject: Technologies