Search

Displaying 176 - 200 of 291 items.

Walter Jakob Gehring (1939-2014)

Walter Jakob Gehring discovered the homeobox, a DNA segment found in a specific cluster of genes that determine the body plan of animals, plants, and fungi. Gehring identified the homeobox in 1983, with the help of colleagues while isolating the Antennapedia (Antp) gene in fruit flies (Drosophila) at the University of Basel in Basel, Switzerland. Hox genes, a family of genes that have the homeobox, determine the head-to-tail (anterior-posterior) body axis of both vertebrates and invertebrates.

Format: Articles

Subject: People

Leuprorelin as a Treatment for Endometriosis

Leuprolide acetate, or leuprorelin, is a manufactured drug that has been prescribed as a treatment for endometriosis, a medical condition in which body tissue that typically lines the uterus grows outside of the uterus, since 1989. Leuprorelin is a modified version of a gonadotropin-releasing hormone, a type of hormone that helps regulate the female menstrual cycle. The drug inhibits the production of estrogen, a female sex hormone that enables endometrial gland growth.

Format: Articles

Subject: Processes

“An Extended Family with a Dominantly Inherited Speech Disorder” (1990), by Jane A. Hurst et al.

In 1990, researcher Jane Hurst and her colleagues published “An Extended Family With a Dominantly Inherited Speech Disorder,” in which they proposed that a single gene was responsible for a language disorder across three generations of a family. Affected individuals of the family, called the KE family, had difficulty producing, expressing and comprehending speech. Hurst and her team studied the KE family and the disorder at the Department of Clinical Genetics at the Great Ormond Street Hospital for Children in London, England.

Format: Articles

Subject: Publications, Disorders

Apoptosis in Embryonic Development

Apoptosis, or programmed cell death, is a mechanism in embryonic development that occurs naturally in organisms. Apoptosis is a different process from cell necrosis, which is uncontrolled cell death usually after infection or specific trauma. As cells rapidly proliferate during development, some of them undergo apoptosis, which is necessary for many stages in development, including neural development, reduction in egg cells (oocytes) at birth, as well as the shaping of fingers and vestigial organs in humans and other animals. Sydney Brenner, H. Robert Horvitz, and John E.

Format: Articles

Subject: Theories

Calvin Blackman Bridges (1889-1938)

Calvin Blackman Bridges studied chromosomes and heredity in the US throughout the early twentieth century. Bridges performed research with Thomas Hunt Morgan at Columbia University in New York City, New York, and at the California Institute of Technology in Pasadena, California. Bridges and Morgan studied heredity in Drosophila, the common fruit fly. Throughout the early twentieth century, researchers were gathering evidence that genes, or what Gregor Mendel had called the factors that control heredity, are located on chromosomes.

Format: Articles

Subject: People

The Discovery of Fetal Alcohol Syndrome

The term Fetal Alcohol Syndrome (FAS) was first published in 1973 in an article published in the British medical journal The Lancet. In that article, a group of pediatricians and psychiatrists at the University of Washington Medical School helped to define the morphological defects and developmental delays that can affect children born to alcoholic mothers. Those observations include pre- and post-natal growth deficiencies, minor facial abnormalities, and damage to the developing brain that can result in behavioral, learning, and cognitive abnormalities.

Format: Articles

Subject: Disorders, Reproduction

Frank Rattray Lillie (1870-1947)

Frank R. Lillie was born in Toronto, Canada, on 27 June 1870. His mother was Emily Ann Rattray and his father was George Waddell Little, an accountant and co-owner of a wholesale drug company. While in high school Lillie took up interests in entomology and paleontology but went to the University of Toronto with the aim of studying ministry. He slowly became disillusioned with this career choice and decided to major in the natural sciences. It was during his senior year that he developed his lifelong interest in embryology.

Format: Articles

Subject: People

Benjamin Harrison Willier (1890-1972)

Benjamin Harrison Willier is considered one of the most versatile embryologists to have ever practiced in the US. His research spanned most of the twentieth century, a time when the field of embryology evolved from being a purely descriptive pursuit to one of experimental research, to that of incorporating molecular biology into the research lab. Willier was born on 2 November 1890 near Weston, Ohio to Mary Alice Ricard. He spent his childhood doing farming chores and running the farm while his father, David Willier worked as a banker.

Format: Articles

Subject: People

Francis Harry Compton Crick (1916-2004)

Francis Harry Compton Crick, who co-discovered the structure of deoxyribonucleic acid (DNA) in 1953 in Cambridge, England, also developed The Central Dogma of Molecular Biology, and further clarified the relationship between nucleotides and protein synthesis. Crick received the Nobel Prize in Physiology or Medicine that he shared with James Watson and Maurice Wilkins in 1962 for their discovery of the molecular structure of DNA.

Format: Articles

Subject: People

Oviraptor philoceratops Dinosaurs

Oviraptor philoceratops was a small bird-like dinosaur that lived about seventy-five million years ago, during the late Cretaceous period. In 1923, George Olsen of the American Museum of Natural History (AMNH) in New York City, New York, discovered the first Oviraptor fossilized skeleton on top of a dinosaur egg nest in the Gobi Desert, Mongolia. Because of the close proximity of dinosaur and nest, when Henry Fairfield Osborn president of the AMNH published on the discovery, he assumed that the Oviraptor had died attempting to steal the eggs.

Format: Articles

Subject: Organisms

Meiosis in Humans

Meiosis, the process by which sexually-reproducing organisms generate gametes (sex cells), is an essential precondition for the normal formation of the embryo. As sexually reproducing, diploid, multicellular eukaryotes, humans rely on meiosis to serve a number of important functions, including the promotion of genetic diversity and the creation of proper conditions for reproductive success.

Format: Articles

Subject: Processes, Reproduction

Alec John Jeffreys (1950–)

Alec John Jeffreys created a process called DNA fingerprinting in the UK during the twentieth century. For DNA fingerprinting, technicians identify a person as the source of a biological sample by comparing the genetic information contained in the person's DNA to the DNA contained in the sample. Jeffreys developed the technique in the 1980s while at the University of Leicester in Leicester, UK. Jeffreys's technique had immediate applications. In forensic science, DNA fingerprinting enabled police to identify suspects of crimes based on their genetic identities.

Format: Articles

Subject: People

William Thornton Mustard (1914-1987)

William Thornton Mustard was a surgeon in Canada during the twentieth century who developed surgical techniques to treat children who had congenital heart defects. Mustard has two surgeries named after him, both of which he helped to develop. The first of these surgeries replaces damaged or paralyzed muscles in individuals who have polio, a virus that can cause paralysis. The other technique corrects a condition called the transposition of the great arteries (TGA) that is noticed at birth.

Format: Articles

Subject: People, Disorders, Disorders

Mary-Claire King (1946– )

Mary-Claire King studied genetics in the US in the twenty-first century. King identified two genes associated with the occurrence of breast cancer, breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2). King showed that mutated BRCA1 and BRCA2 genes cause two types of reproductive cancer, breast and ovarian cancer. Because of King’s discovery, doctors can screen women for the inheritance of mutated BRCA1 and BRCA2 genes to evaluate their risks for breast and ovarian cancer.

Format: Articles

Subject: People

Jerold Lucey (1926– )

Jerold Lucey studied newborn infants in the United States in the twentieth century. In the 1960s and 1970s, Lucey studied phototherapy as a treatment for jaundice, a condition in infants whose livers cannot excrete broken down red blood cells, called bilirubin, into the bloodstream at a fast enough rate. In addition to his work in jaundice, Lucey was the editor in chief for the journal Pediatrics of the American Academy of Pediatrics.

Format: Articles

Subject: People

Henry Morgentaler (1923-2013)

Henry Morgentaler was a physician who performed abortions, acted as a reproductive rights activist, and advocated for legal access to abortions in Canada during the twentieth century. In 1969, he opened his first abortion clinic in Canada and participated in the legal/court case of R v. Morgentaler (1988), which led Canada to decriminalize abortion. Morgentaler helped establish legal access to abortions for women in Canada and advocated for the protection of women's reproductive choices under the law.

Format: Articles

Subject: People

Richard Doll (1912–2005)

Richard Doll was an epidemiologist and public figure in the twentieth and early twenty-first centuries. Working primarily at the University of Oxford, in Oxford, England, Doll established a definitive correlation between cigarette smoking and lung cancer. Furthermore, Doll’s work helped legitimize epidemiology as a scientific discipline. Doll’s research also helped establish modern guidelines for oncological studies, as well as for contemporary and future research on the effect of smoking on pregnancy and fetal development.

Format: Articles

Subject: People

David Baltimore (1938– )

David Baltimore studied viruses and the immune system in the US during the twentieth century. In 1975, Baltimore was awarded the Nobel Prize in Physiology or Medicine for discovering reverse transcriptase, the enzyme used to transfer information from RNA to DNA. The discovery of reverse transcriptase contradicted the central dogma of biology at the time, which stated that the transfer of information was unidirectional from DNA, RNA, to protein.

Format: Articles

Subject: People

Francois Jacob (1920-2013)

Francois Jacob studied in
bacteria and bacteriophages at the Institut Pasteur in Paris, France,
in the second half of the twentieth century. In 1965, Jacob won the
Nobel Prize in Physiology or Medicine with Andre M. Lwoff and
Jacques L. Monod for their work on the genetic control of enzyme
synthesis. Jacob studied how genes control and regulate metabolic
enzymes in the bacterium Escherichia
coli (E. coli) and in lysogenic
bacterial systems. He contributed to theories of transcriptional gene

Format: Articles

Subject: People

Alfred Day Hershey (1908–1997)

During the twentieth century in the United States, Alfred Day Hershey studied phages, or viruses that infect bacteria, and experimentally verified that genes were made of deoxyribonucleic acid, or DNA. Genes are molecular, heritable instructions for how an organism develops. When Hershey started to study phages, scientists did not know if phages contained genes, or whether genes were made of DNA or protein. In 1952, Hershey and his research assistant, Martha Chase, conducted phage experiments that convinced scientists that genes were made of DNA.

Format: Articles

Subject: People

Studies of Thalidomide's Effects on Rodent Embryos from 1962-2008

Thalidomide is a sedative drug introduced to European markets on 1 October 1957 after extensive testing on rodent embryos to ensure its safety. Early laboratory tests in rodent populations showed that pregnant rodents could safely use it, so doctors prescribed Thalidomide to treat morning sickness in pregnant women. However, in humans Thalidomide interfered with embryonic and fetal development in ways not observed in rodent tests.

Format: Articles

Subject: Organisms, Reproduction, Disorders

Torsten Wiesel (1924– )

Torsten Nils Wiesel studied visual information processing and development in the US during the twentieth century. He performed multiple experiments on cats in which he sewed one of their eyes shut and monitored the response of the cat’s visual system after opening the sutured eye. For his work on visual processing, Wiesel received the Nobel Prize in Physiology or Medicine in 1981 along with David Hubel and Roger Sperry.

Format: Articles

Subject: People

Ian Donald (1910–1987)

Ian Donald was an obstetrician who developed the technology and therapy of ultrasound diagnostics during the twentieth century in Europe. Ultrasound is a medical diagnostic technique that uses sound waves to produce images of the inside of the body. During the early 1900s, physicians had no way to see inside a woman’s uterus during pregnancy. Donald developed the first method of scanning human internal anatomy in real time, which enabled doctors to diagnose potentially fatal tumors and cysts.

Format: Articles

Subject: People

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

The Notch Signaling Pathway in Embryogenesis

The Notch signaling pathway is a mechanism in animals by which adjacent cells communicate with each other, conveying spatial information and genetic instructions for the animal's development. All multicellular animals utilize Notch signaling, which contributes to the formation, growth, and development of embryos (embryogenesis). Notch signaling also contributes to the differentiation of embryonic cells into various types of cells into various types of cells, such as neurons.

Format: Articles

Subject: Processes