Experiments

"In vitro Experiments on the Effects of Mouse Sarcomas 180 and 37 on the Spinal and Sympathetic Ganglia of the Chick Embryo" (1954), by Rita Levi-Montalcini, Viktor Hamburger, and Hertha Meyer

By Adam R. Navis

"In vitro Experiments on the Effects of Mouse Sarcomas 180 and 37 on the Spinal and Sympathetic Ganglia of the Chick Embryo" were experiments conducted by Rita Levi-Montalcini in conjunction with Viktor Hamburger and Hertha Meyer and published in Cancer Research in 1954. In this series of experiments, conducted at the University of Brazil, Levi-Montalcini demonstrated increased nerve growth by introducing specific tumors (sarcomas) to chick ganglia. Ganglia are clusters of nerve cells, from which nerve fibers emerge.

Created 2007-10-30

Last modified 2 years 2 months ago

Format: Articles

"Proliferation, Differentiation and Degeneration in the Spinal Ganglia of the Chick Embryo under Normal and Experimental Conditions" (1949), by Viktor Hamburger and Rita Levi-Montalcini

By Adam R. Navis

In this paper Viktor Hamburger and Rita Levi-Montalcini collaborated to examine the effects of limb transplantation and explantation on neural development. In 1947 Hamburger invited Levi-Montalcini to his lab at Washington University in St. Louis to examine this question. Independently, each had previously arrived at opposing conclusions based on the same data.

Created 2007-10-30

Last modified 2 years 2 months ago

Format: Articles

"Purification of a Nerve-Growth Promoting Protein from the Mouse Salivary Gland and its Neuro-Cytoxic Antiserum" (1960), by Stanley Cohen

By Adam R. Navis

Stanley Cohen published "Purification of a Nerve-Growth Promoting Protein from the Mouse Salivary Gland and its Neuro-Cytoxic Antiserum" in the Proceedings of the National Academies of Sciences in 1960. This paper outlined the successful purification and identification of nerve growth factor (NGF) as a protein, the developmental effects of depriving an embryo of NGF, and the discovery that NGF is also required for the maintenance of the nervous system.

Created 2007-10-30

Last modified 2 years 2 months ago

Format: Articles

"Selective Growth Stimulating Effects of Mouse Sarcoma on the Sensory and Sympathetic Nervous System of the Chick Embryo" (1951), by Rita Levi-Montalcini and Viktor Hamburger

By Adam R. Navis

In "Selective Growth Stimulating Effects of Mouse Sarcoma on the Sensory and Sympathetic Nervous System of the Chick Embryo," Rita Levi-Montalcini and Viktor Hamburger explored the effects of two nerve growth stimulating tumors; mouse sarcomas 180 and 37. This experiment led to the discovery that nerve growth factor was a diffusible chemical and later to discoveries that the compound was a protein. Although this paper was an important step in the discovery of nerve growth factor, the term "nerve growth factor" was not used in this paper.

Created 2007-10-30

Last modified 2 years 2 months ago

Format: Articles

"Interspecific Chimeras in Mammals: Successful Production of Live Chimeras Between Mus musculus and Mus caroli" (1980), by Janet Rossant and William I. Frels

By Nicole Newkirk

In 1980 Janet Rossant and William I. Frels published their paper, "Interspecific Chimeras in Mammals: Successful Production of Live Chimeras Between Mus musculus and Mus caroli," in Science. Their experiment involved the first successful creation of interspecific mammalian chimeras. Mammalian chimeras are valuable for studying early embryonic development. However, in earlier studies, clonal analysis was restricted by the lack of a cell marker, present at all times, that makes a distinction between the two parental cell types in situ.

Created 2007-10-30

Last modified 2 years 2 months ago

Format: Articles

"Experiments on Embryonic Induction III. A Note on Inductions by Chick Primitive Streak Transplanted to the Rabbit Embryo" (1934), by Conrad Hal Waddington

By Adam R. Navis

Conrad Hal Waddington's "Experiments on Embryonic Induction III," published in 1934 in the Journal of Experimental Biology, describes the discovery that the primitive streak induces the mammalian embryo. Waddington's hypothesis was that a transplanted primitive streak could induce neural tissue in the ectoderm of the rabbit embryo. The primitive streak defines the axis of an embryo and is capable of inducing the differentiation of various tissues in a developing embryo during gastrulation.

Created 2007-10-30

Last modified 2 years 2 months ago

Format: Articles

"A Series of Normal Stages in the Development of the Chick Embryo" (1951), by Viktor Hamburger and Howard L. Hamilton

By Adam R. Navis

The developmental stages of the chick embryo were examined by Viktor Hamburger and Howard L. Hamilton in "A Series of Normal Stages in the Development of the Chick Embryo," published in the Journal of Morphology in 1951. These stages were published to standardize the development of the chick based on varying laboratory conditions and genetic differences. The stages Hamburger and Hamilton assigned were determined by the visible features of the chick embryo.

Created 2007-10-30

Last modified 2 years 2 months ago

Format: Articles

"Experiments on the Development of Chick and Duck Embryos, Cultivated in vitro" (1932), by Conrad Hal Waddington

By Adam R. Navis

Conrad Hal Waddington's "Experiments on the Development of Chick and Duck Embryos, Cultivated in vitro," published in 1932 in Philosophical Transactions of the Royal Society of London, Series B, compares the differences in the development of birds and amphibians. Previous experiments focused on the self differentiation of individual tissues in birds, but Waddington wanted to study induction in greater detail. The limit to these studies had been the amount of time an embryo could be successfully cultivated ex vivo.

Created 2007-11-08

Last modified 2 years 2 months ago

Format: Articles

"Experiments in Transplanting Limbs and Their Bearing Upon the Problems of the Development of Nerves" (1907), by Ross Granville Harrison

By Adam R. Navis

In his 1907 paper, "Experiments in Transplanting Limbs and Their Bearing Upon the Problems of the Development of Nerves," in the Journal of Experimental Zoology that he edited, Ross Granville Harrison tested the development of nerves in transplanted tissue. He studied neural development by examining two competing theories. Victor Hensen proposed a syncytial theory as a way to explain neural development, suggesting that all the nerves of an embryo were connected directly by cytoplasm laid down early in development, and leaving no room for later modification.

Created 2007-11-08

Last modified 2 years 2 months ago

Format: Articles

"A Diffusible Agent of Mouse Sarcoma, Producing Hyperplasia of Sympathetic Ganglia and Hyperneurotization of Viscera in the Chick Embryo" (1953), by Rita Levi-Montalcini and Viktor Hamburger

By Adam R. Navis

"A Diffusible Agent of Mouse Sarcoma, Producing Hyperplasia of Sympathetic Ganglia and Hyperneurotization of Viscera in the Chick Embryo," by Rita Levi-Montalcini and Viktor Hamburger, appeared in 1953 in the Journal of Experimental Zoology. The paper provided the first evidence that nerve growth factor is a diffusible substance. Nerve growth promoting tumors were implanted into developing embryos to determine whether the tumors stimulated growth by direct contact or by a diffusible substance.

Created 2007-11-09

Last modified 2 years 2 months ago

Format: Articles

"Transplantation of Living Nuclei from Blastula Cells into Enucleated Frogs' Eggs" (1952), by Robert Briggs and Thomas J. King

By Nicole Newkirk

In 1952 Robert Briggs and Thomas J. King published their article, "Transplantation of Living Nuclei from Blastula Cells into Enucleated Frogs' Eggs," in the Proceedings of the National Academy of Sciences, the culmination of a series of experiments conducted at the Institute for Cancer Research and Lankenau Hospital Research Institute in Philadelphia, Pennsylvania. In this paper Briggs and King examined whether nuclei of embryonic cells are differentiated, and by doing so, were the first to conduct a successful nuclear transplantation with amphibian embryos.

Created 2007-11-13

Last modified 2 years 2 months ago

Format: Articles

"Versuche zur Analyse der Induktionsmittel in der Embryonalentwicklung" (1932), by Hermann Bautzmann, Johannes Holtfreter, Otto Mangold, and Hans Spemann

By Adam R. Navis

In "Versuche zur Analyse der Induktionsmittel in der Embryonalentwicklung," published in Naturwissenschaften in 1932, Hermann Bautzmann, Johannes Holtfreter, Otto Mangold, and Hans Spemann jointly reported on experiments each had conducted testing the activity of organizers killed by boiling, freezing, alcohol, and drying. Each of the authors had been independently conducting similar experiments, when Holtfreter made a breakthrough allowing him to produce many more successful transplantations.

Created 2007-11-13

Last modified 2 years 2 months ago

Format: Articles

"The Outgrowth of the Nerve Fiber as a Mode of Protoplasmic Movement" (1910), by Ross Granville Harrison

By Adam R. Navis

In "The Outgrowth of the Nerve Fiber as a Mode of Protoplasmic Movement," Ross Granville Harrison explores the growth of nerve fibers in vitro. The purpose of this experiment was to test two possible hypotheses for the growth of nerve fibers. Santiago Ramón y Cajal suggested that nerve growth is due to the extension of nerve fibers as they push through tissue. Victor Hensen's syncytial theory proposed an opposing view of nerve growth.

Created 2007-11-13

Last modified 2 years 2 months ago

Format: Articles

"Experimental Chimeras' Removal of Reproductive Barrier Between Sheep and Goat" (1984), by Sabine Meinecke-Tillmann and Burkhard Meinecke

By Nicole Newkirk

In 1984 Sabine Meinecke-Tillmann and Burkhard Meinecke published their article "Experimental Chimeras - Removal of Reproductive Barrier Between Sheep and Goat" in Nature. Their study conquered the reproductive barrier between sheep and goats through embryo manipulation. Their article appeared in Nature on the same day that a similar experiment, conducted by Carole Fehilly, Steen Willadsen, and Elizabeth Tucker was published regarding reproductive barriers between sheep and goats.

Created 2008-02-28

Last modified 2 years 2 months ago

Format: Articles

"Formation of Genetically Mosaic Mouse Embryos and Early Development of Lethal (t12/t12)-Normal Mosaics" (1964), by Beatrice Mintz

By Adam R. Navis

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.

Created 2009-01-13

Last modified 2 years 2 months ago

Format: Articles

Rock-Menkin Experiments

By Stephen Ruffenach

Dr. John Rock, a doctor of obstetrics and gynecology in Boston, and Miriam Menkin, Rock s hired lab technician, were the first researchers to fertilize a human egg outside of a human body in February of 1944. Their work was published on 4 August 1944 in an issue of Science in an article entitled "In Vitro Fertilization and Cleavage of Human Ovarian Eggs." This experiment marked the first time in history that a human embryo was produced outside of the human body, proving that in vitro fertilization was possible in humans.

Created 2009-01-13

Last modified 3 years 8 months ago

Format: Articles

"Experiments on Artificial Parthenogenesis in Annelids (Chaetopterus) and the Nature of the Process of Fertilization" (1901), by Jacques Loeb

By Steve Elliott

Jacques Loeb showed that scientists could achieve artificial parthenogenesis with some types of annelid worm eggs through a series of experiments in 1900. Loeb published the results of his experiments in 1901 as "Experiments on Artificial Parthenogenesis in Annelids (Chaetopterus) and the Nature of the Process of Fertilization," in The American Journal of Physiology. Loeb 's results broadened the range of animals to which artificial parthenogenesis applied beyond sea urchins.

Created 2009-06-10

Last modified 3 years 8 months ago

Format: Articles

"Further Experiments on Artificial Parthenogenesis and the Nature of the Process of Fertilization" (1900), by Jacques Loeb

By Steve Elliott

Jacques Loeb broadened and corrected his earlier claims concerning artificial parthenogenesis in sea urchins in a series of experiments in 1900. He published these findings, "Further Experiments on Artificial Parthenogenesis and the Nature of The Process of Fertilization," in a 1900 issue of The American Journal of Physiology.

Created 2009-06-10

Last modified 3 years 8 months ago

Format: Articles

"Contributions to the Development of the Embryo. On the Artificial Production of One of the First Two Blastomeres, and the Later Development (Postgeneration) of the Missing Half of the Body" (1888), by Wilhelm Roux

By Megan Kearl

Wilhelm Roux was an influential figure in the early history of experimental embryology. Although he originally studied medicine, he was invited to be a Privatdozentur, or unsalaried lecturer, at the Anatomical Institute in Breslau (Wroclaw), Poland, in 1879. He spent the next ten years at this institute, working his way from Dozent to associate professor and finally, in 1889, to director for his own institute, Institut für Entwicklungsgeschichte, or Institute for Developmental History and Mechanics.

Created 2009-07-20

Last modified 2 years 2 months ago

Format: Articles

"β-Catenin Defines Head Versus Tail Identity During Planarian Regeneration and Homeostasis" (2007), by Kyle A. Gurley, Jochen C. Rink, and Alejandro Sánchez Alvarado

By Mary E. Sunderland

Alejandro Sánchez Alvarado's laboratory group has employed molecular tools to investigate old questions about regeneration and as a result have identified some of the molecular mechanisms determining polarity. Recent work by his group has shown Wnt-β-catenin signaling determines whether a tail or a head will form during regeneration in planarians. This study was motivated by work Thomas Hunt Morgan conducted in the late nineteenth century.

Created 2010-03-15

Last modified 2 years 1 month ago

Format: Articles

"On the Nature of the Process of Fertilization and the Artificial Production of Normal Larvae (Plutei) From the Unfertilized Eggs of the Sea Urchin" (1899), by Jacques Loeb

By Steve Elliott

Jacques Loeb developed procedures to make embryos from unfertilized sea urchin eggs in 1899. Loeb called the procedures "artificial parthenogenesis," and he introduced them and his results in "On the Nature of the Process of Fertilization and the Artificial Production of Norma Larvae (Plutei) from the Unfertilized Eggs of the Sea Urchin" in an 1899 issue of The American Journal of Physiology. In 1900 Loeb elaborated on his experiments.

Created 2010-06-10

Last modified 3 years 8 months ago

Format: Articles

Viktor Hamburger's Study of Central-Peripheral Relations in the Development of Nervous System

By Lijing Jiang

An important question throughout the history of embryology is whether the formation of a biological structure is predetermined or shaped by its environment. If both intrinsic and environmental controls occur, how exactly do the two processes coordinate in crafting specific forms and functions? When Viktor Hamburger started his PhD study in embryology in the 1920s, few neuroembryologists were investigating how the central neurons innervate peripheral organs.

Created 2010-11-19

Last modified 3 years 8 months ago

Format: Articles

"Generation of Induced Pluripotent Stem Cells without Myc from Mouse and Human Fibroblasts" (2007), by Masato Nakagawa et al.

By Samuel Philbrick

In November 2007, Masato Nakagawa, along with a number of other researchers including Kazutoshi Takahashi, Keisuke Okita, and Shinya Yamanaka, published "Generation of Induced Pluripotent Stem Cells without Myc from Mouse and Human Fibroblasts" (abbreviated "Generation") in Nature. In "Generation," the authors point to dedifferentiation of somatic cells as an avenue for generating pluripotent stem cells useful for treating specific patients and diseases.

Created 2010-11-20

Last modified 2 years 1 month ago

Format: Articles

"The Effects of Wing Bud Extirpation on the Development of the Central Nervous System in Chick Embryos" (1934), by Viktor Hamburger

By Lijing Jiang

German embryologist Viktor Hamburger came to the US in 1932 with a fellowship provided by the Rockefeller Foundation. Hamburger started his research in Frank Rattray Lillie's laboratory at the University of Chicago. His two-year work on the development of the central nervous system (CNS) in chick embryos was crystallized in his 1934 paper, "The Effects of Wing Bud Extirpation on the Development of the Central Nervous System in Chick Embryos," published in The Journal of Experimental Zoology.

Created 2010-11-22

Last modified 2 years 1 month ago

Format: Articles

The Discovery of p53 Protein

By Lijing Jiang

The p53 protein acts as a pivotal suppressor of inappropriate cell proliferation. By initiating suppressive effects through induction of apoptosis, cell senescence, or transient cell-cycle arrest, p53 plays an important role in cancer suppression, developmental regulation, and aging. Its discovery in 1979 was a product of research into viral etiology and the immunology of cancer. The p53 protein was first identified in a study of the role of viruses in cancer through its ability to form a complex with viral tumor antigens.

Created 2011-01-21

Last modified 3 years 8 months ago

Format: Articles

Nicole Le Douarin and Charles Ordahl's Experiments on the Developmental Lineages of Somites

By Corinne DeRuiter

Through various studies developmental biologists have been able to determine that the muscles of the back, ribs, and limbs derive from somites. Somites are blocks of cells that contain distinct sections that diverge into specific types (axial or limb) of musculature and are an essential part of early vertebrate development. For many years the musculature of vertebrates was known to derive from the somites, but the exact developmental lineage of axial and limb muscle progenitor cells remained a mystery until Nicole Le Douarin and Charles P.

Created 2011-01-31

Last modified 3 years 8 months ago

Format: Articles

"Embryonic Stem Cell Lines Derived from Human Blastocytes" (1998), by James Thomson

By Ke Wu

After becoming chief pathologist at the University of Wisconsin-Madison Wisconsin Regional Primate Center in 1995, James A. Thomson began his pioneering work in deriving embryonic stem cells from isolated embryos. That same year, Thomson published his first paper, "Isolation of a Primate Embryonic Stem Cell Line," in Proceedings of the National Academy of Sciences of the United States of America, detailing the first derivation of primate embryonic stem cells. In the following years, Thomson and his team of scientists - Joseph Itskovitz-Eldor, Sander S. Shapiro, Michelle A.

Created 2011-02-01

Last modified 2 years 1 month ago

Format: Articles

Robert Geoffrey Edwards's Study of Fertilization of Human Oocytes Matured in vitro, 1965 to 1969

By Lijing Jiang

Robert Geoffrey Edwards, a British developmental biologist at University of Cambridge, began exploring human in vitro fertilization (IVF) as a way to treat infertility in 1960. After successfully overcoming the problem of making mammalian oocytes mature in vitro in 1965, Edwards began to experiment with fertilizing matured eggs in vitro. Collaborating with other researchers, Edwards eventually fertilized a human egg in vitro in 1969. This was a huge step towards establishing human IVF as a viable fertility treatment.

Created 2011-03-10

Last modified 3 years 8 months ago

Format: Articles

China's First Baby Conceived through In Vitro Fertilization-Embryonic Transfer, by Zhang Lizhu's Research Team

By Lijing Jiang

On 10 March 1988, China's first baby conceived through human in vitro fertilization (IVF) and embryo transfer (ET), commonly referred to as a test-tube baby, was born at the Peking Hospital (PUTH) in Beijing. This birth was reported in numerous media reports as a huge step forward in China's long march to keep pace with global advances in science and technology. Led by gynecologist Zhang Lizhu, the PUTH research team had devoted more than four years to the human IVF-ET project.

Created 2011-04-27

Last modified 3 years 8 months ago

Format: Articles

"Programmed Cell Death-II. Endocrine Potentiation of the Breakdown of the Intersegmental Muscles of Silkmoths" (1964), by Richard A. Lockshin and Carroll M. Williams

By Lijing Jiang

Richard A. Lockshin's 1963 PhD dissertation on cell death in insect metamorphosis was conducted under the supervision of Harvard insect physiologist Carroll M. Williams. Lockshin and Williams used this doctoral research as the basis for five articles, with the main title "Programmed Cell Death," that were published between 1964 and 1965 in the Journal of Insect Physiology. These articles examine the cytological processes, neuronal and endocrinal controls, and the influence of drugs on the mechanism of cell death observed in pupal muscle structures of the American silkmoth.

Created 2011-04-27

Last modified 2 years 1 month ago

Format: Articles

Robert Geoffrey Edwards and Patrick Christopher Steptoe's Clinical Research in Human in vitro Fertilization and Embryo Transfer, 1969-1980

By Lijing Jiang

The biomedical accomplishment of human in vitro fertilization and embryo transfer (IVF-ET) took years to become the successful technique that presently enables infertile couples to have their own children. In 1969, more than ten years after the first attempts to treat infertilities with IVF technologies, the British developmental biologist Robert Geoffrey Edwards fertilized human oocytes in a Petri dish for the first time.

Created 2011-05-12

Last modified 3 years 8 months ago

Format: Articles

"Developmental Capacity of Nuclei Transplanted from Keratinized Skin Cells of Adult Frogs" (1975), by John Gurdon, Ronald Laskey, and O. Raymond Reeves

By Sean Cohmer

In 1975 John Gurdon, Ronald Laskey, and O. Raymond Reeves published "Developmental Capacity of Nuclei Transplanted from Keratinized Skin Cells of Adult Frogs," in the Journal of Embryology and Experimental Morphology. Their article was the capstone of a series of experiments performed by Gurdon during his time at Oxford and Cambridge, using the frog species Xenopus laevis. Gurdon's first experiment in 1958 showed that the nuclei of Xenopus cells maintained their ability to direct normal development when transplanted.

Created 2011-06-14

Last modified 2 years 1 month ago

Format: Articles

"The Development of the Turtle Carapace" (1989), by Ann Campbell Burke

By Guido Caniglia

Ann Campbell Burke examines the development and evolution of vertebrates, in particular, turtles. Her Harvard University experiments, described in Development of the Turtle Carapace: Implications for the Evolution of a Novel Bauplan, were published in 1989. Burke used molecular techniques to investigate the developmental mechanisms responsible for the formation of the turtle shell.

Created 2011-10-20

Last modified 3 years 8 months ago

Format: Articles

David Wildt's Domestic Cat and Cheetah Experiments (1978-1983)

By Caroline Appleton

David Wildt's cheetah (Acinonyx jubatus) research from 1978-1983 became the foundation for the use of embryological techniques in endangered species breeding programs. The cheetah is a member of the cat family (Felidae), which includes thirty-seven species. According to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) all Felidae species are currently threatened or endangered, with the exception of the domestic cat (Felinus catus).

Created 2011-12-19

Last modified 3 years 8 months ago

Format: Articles

"The Potency of the First Two Cleavage Cells in Echinoderm Development. Experimental Production of Partial and Double Formations" (1891-1892), by Hans Driesch

By Megan Kearl

Hans Adolf Eduard Driesch was a late-nineteenth and early-twentieth century philosopher and developmental biologist. In the spring of 1891 Driesch performed experiments using two-celled sea urchin embryos, the results of which challenged the then-accepted understanding of embryo development. Driesch showed that the cells of an early embryo, when separated, could each continue to develop into normal larval forms.

Created 2012-01-01

Last modified 3 years 8 months ago

Format: Articles

"How do Embryos Assess Risk? Vibrational Cues in Predator-Induced Hatching of Red-Eyed Treefrogs" (2005), by Karen Warkentin

By Karla T. Moeller

In 'How do Embryos Assess Risk? Vibrational Cues in Predator-Induced Hatching of Red-Eyed Treefrogs' (2005), Karen Warkentin reported on experiments she conducted to see how red-eyed treefrog embryos, Agalychnis callidryas, can distinguish between vibrations due to predator attacks and other environmental occurrences, such as storms. Though the ability of red-eyed treefrogs to alter their hatch timing had been documented, the specific cues that induce early hatching were not well understood.

Created 2012-04-07

Last modified 2 years 3 months ago

Format: Articles

"On the Permanent Life of Tissues outside of the Organism" (1912), by Alexis Carrel

By Lijing Jiang

'On the Permanent Life of Tissues outside of the Organism' reports Alexis Carrel's 1912 experiments on the maintenance of tissue in culture media. At the time, Carrel was a French surgeon and biologist working at the Rockefeller Institute in New York City. In his paper, Carrel reported that he had successfully maintained tissue cultures, which derived from connective tissues of developing chicks and other tissue sources, by serially culturing them.

Created 2012-05-06

Last modified 2 years 3 months ago

Format: Articles

Alexis Carrel's Immortal Chick Heart Tissue Cultures (1912-1946)

By Lijing Jiang

In an effort to develop tissue culture techniques for long-term tissue cultivation, French surgeon and biologist Alexis Carrel, and his associates, produced and maintained a series of chick heart tissue cultures at the Rockefeller Institute in New York City. From 1912 to 1946, this series of chick heart tissue cultures remained alive and dividing. Since the duration of this culture greatly exceeded the normal chick life span, the cells were deemed immortal.

Created 2012-07-03

Last modified 2 years 3 months ago

Format: Articles

Gastrulation in Mus musculus (common house mouse)

By Justin M. Wolter

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.

Created 2012-10-04

Last modified 2 years 3 months ago

Format: Articles

"On the Induction of Embryonic Primordia by Implantation of Organizers from Different Species" (1924), Hilde Mangold's Dissertation

By Megan Kearl, Kate MacCord

Hilde Proscholdt Mangold was a doctoral student at the Zoological Institute at the University of Freiburg in Freiburg, Germany, from 1920-1923. Mangold conducted research for her dissertation 'On the Induction of Embryonic Primordia by Implantation of Organizers from Different Species' ('Ueber Induktion von Embryonanlagen durch Implantation artfremder Organisatoren'), under the guidance of Hans Spemann, a professor of zoology at the University of Freiburg.

Created 2012-12-19

Last modified 7 months 3 weeks ago

Format: Articles

Corticosteroids' Effect on Fetal Lung Maturation (1972), by Sir Graham Collingwood Liggins and Ross Howie

By Kathleen O'Connor, Erica O'Neil

In a clinical trial from 1969 to 1972, Sir Graham Collingwood Liggins and Ross Howie showed that if doctors treat pregnant women with corticosteroids before those women deliver prematurely, then those women's infants have fewer cases of respiratory distress syndrome than do similarly premature infants of women not treated with corticosteroids. Prior to the study, premature infants born before 32 weeks of gestation often died of respiratory distress syndrome, or the inability to inflate immature lungs.

Created 2012-12-19

Last modified 7 months 3 weeks ago

Format: Articles

"Maternal consumption of peanut during pregnancy is associated with peanut sensitization in atopic infants" (2010), by Scott Sicherer, et al.

By Maggie Pingolt

In 2010, a team of US researchers concluded that the more peanuts a pregnant woman ate during her pregnancy, the more likely her newborn was to be sensitive to peanuts. They published their results in 2010's "Maternal consumption of peanut during pregnancy is associated with peanut sensitization in atopic infants." The work resulted from the collaboration of Scott Sicherer and Hugh Sampson, both from the Jaffe Food Allergy Institute, Mount Sinai School of Medicine, in New York, New York along with other colleagues.

Created 2013-01-30

Last modified 2 years 3 months ago

Format: Articles

Temperature-Dependent Sex Determination in Reptiles

By Karla T. Moeller

The sex of a reptile embryo partly results from the production of sex hormones during development, and one process to produce those hormones depends on the temperature of the embryo's environment. The production of sex hormones can result solely from genetics or from genetics in combination with the influence of environmental factors. In genotypic sex determination, also called genetic or chromosomal sex determination, an organism's genes determine which hormones are produced.

Created 2013-02-01

Last modified 2 years 3 months ago

Format: Articles

The inductive capacity of oral mesenchyme and its role in tooth development (1969-1970), by Edward J. Kollar and Grace R. Baird

By Kate MacCord

Between February 1969 and August 1970 Edward Kollar and Grace Baird, from the University of Chicago in Chicago, Illinois, published three papers that established the role of the mesenchyme in tooth induction. Drawing upon a history of using tissue interactions to understand differentiation, Kollar and Baird designed their experiments to understand how differentiated structures become specified. Their work overturned a widely accepted model that epithelium controls the identity of the structure, a phenomenon called structural specificity.

Created 2013-03-15

Last modified 2 years 3 months ago

Format: Articles

The First Successful Cloning of a Gaur (2000), by Advanced Cell Technology

By Caroline Appleton

Advanced Cell Technology (ACT), a stem cell biotechnology company in Worcester, Massachusetts, showed the potential for cloning to contribute to conservation efforts. In 2000 ACT researchers in the United States cloned a gaur (Bos gaurus), an Asian ox with a then declining wild population. The researchers used cryopreserved gaur skin cells combined with an embryo of a domestic cow (Bos taurus). A domestic cow also served as the surrogate for the developing gaur clone.

Created 2013-07-26

Last modified 2 years 3 months ago

Format: Articles

"Experiments in Plant Hybridization" (1866), by Johann Gregor Mendel

By Amanda Andrei

During the mid-nineteenth century, Johann Gregor Mendel experimented with pea plants to develop a theory of inheritance. In 1843, while a monk in the Augustian St Thomas's Abbey in Brünn, Austria, now Brno, Czech Repubic, Mendel examined the physical appearance of the abbey's pea plants (Pisum sativum) and noted inconsistencies between what he saw and what the blending theory of inheritance, a primary model of inheritance at the time, predicted.

Created 2013-09-04

Last modified 2 years 3 months ago

Format: Articles

"Development, Plasticity and Evolution of Butterfly Eyespot Patterns" (1996), by Paul M. Brakefield et al.

By Yawen Zou

Paul M. Brakefield and his research team in Leiden, the Netherlands, examined the development, plasticity, and evolution of butterfly eyespot patterns, and published their findings in Nature in 1996. Eyespots are eye-shaped color patterns that appear on the wings of some butterflies and birds as well as on the skin of some fish and reptiles. In butterflies, such as the peacock butterfly Aglais, the eyespots resemble the eyes of birds and help butterflies deter potential predators.

Created 2013-09-10

Last modified 2 years 1 month ago

Format: Articles

"The Adaptive Significance of Temperature-Dependent Sex Determination in a Reptile" (2008), by Daniel Warner and Richard Shine

By Karla Moeller

In 2008 researchers Daniel Warner and Richard Shine tested the Charnov-Bull model by conducting experiments on the Jacky dragon (Amphibolurus muricatus), in Australia. Their results showed that temperature-dependent sex determination(TSD) evolved in this species as an adaptation to fluctuating environmental temperatures. The Charnov-Bull model, proposed by Eric Charnov and James Bull in 1977, described the evolution of TSD, although the model was, for many years, untested.

Created 2013-10-07

Last modified 2 years 3 months ago

Format: Articles

"Genetic Evidence Equating SRY and the Testis-Determining Factor" (1990), by Phillippe Berta et al.

By Troy Cox

In the late 1980s, Peter Goodfellow in London, UK led a team of researchers who showed that the SRY gene in humans codes a protein that causes testes to develop in embryos. During this time, scientists in London and Paris, including Peter Koompan and John Gubbay, proposed that SRY was the gene on the Y chromosome responsible for encoding the testis-determining factor (TDF) protein. The TDF is a protein that initiates embryo to develop male characteristics.

Created 2014-01-10

Last modified 2 years 5 months ago

Format: Articles

"Male Development of Chromosomally Female Mice Transgenic for Sry gene" (1991), by Peter Koopman, et al.

By Troy Cox

Early 1990s research conducted by Peter Koopman, John Gubbay, Nigel Vivian, Peter Goodfellow, and Robin Lovell-Badge, showed that chromosomally female (XX) mice embryos can develop as male with the addition of a genetic fragment from the Y chromosome of male mice. The genetic fragment contained a segment of the mouse Sry gene, which is analogous to the human SRY gene. The researchers sought to identify Sry gene as the gene that produced the testis determining factor protein (Tdf protein in mice or TDF protein in humans), which initiates the formation of testis.

Created 2014-01-28

Last modified 2 years 5 months ago

Format: Articles

Pages