Experiments

Displaying 41 - 50 of 126 items.

"Presence of Fetal DNA in Maternal Plasma and Serum" (1997), by Dennis Lo, et al.

By Cassidy Possehl

In the late 1990s researchers Yuk Ming Dennis Lo and his colleagues isolated fetal DNA extracted from pregnant woman’s blood. The technique enabled for more efficient and less invasive diagnoses of genetic abnormalities in fetuses, such as having too many copies of chromosomes.

Format: Articles

Subject: Experiments

Hermann Joseph Muller's Study of X-rays as a Mutagen, (1926-1927)

By Kevin M. Gleason

Hermann Joseph Muller conducted three experiments in 1926 and 1927 that demonstrated that exposure to x-rays, a form of high-energy radiation, can cause genetic mutations, changes to an organism's genome, particularly in egg and sperm cells. In his experiments, Muller exposed fruit flies (Drosophila) to x-rays, mated the flies, and observed the number of mutations in the offspring. In 1927, Muller described the results of his experiments in "Artificial Transmutation of the Gene" and "The Problem of Genic Modification".

Format: Articles

Subject: Experiments

Julia Barlow Platt's Embryological Observations on Salamanders' Cartilage (1893)

By Karina Ramirez

In 1893, Julia Barlow Platt published her research on the origins of cartilage in the developing head of the common mudpuppy (Necturus maculosus) embryo. The mudpuppy is an aquatic salamander commonly used by embryologists because its large embryonic cells and nuclei are easy to see. Platt followed the paths of cells in developing mudpuppy embryos to see how embryonic cells migrated during the formation of the head. With her research, Platt challenged then current theories about germ layers, the types of cells in an early embryo that develop into adult cells.

Format: Articles

Subject: Experiments, Theories, Processes

Edgar Allen and Edward A. Doisy's Extraction of Estrogen from Ovarian Follicles, (1923)

By Brendan Van Iten

In the early 1920s, researchers Edgar Allen and Edward Adelbert Doisy conducted an experiment that demonstrated that ovarian follicles, which produce eggs in mammals, also contain and produce what they called the primary ovarian hormone, later renamed estrogen. In their experiment, Doisy and Allen extracted estrogen from the ovarian follicles of hogs and proved that they had isolated estrogen by using a measurement later renamed the Allen-Doisy test.

Format: Articles

Subject: Experiments

The Effectiveness of Phototherapy in Premature Infants (1968)

By Arianna Bradley

In 1968, pediatric researchers Jerold Lucey, Mario Ferreiro, and Jean Hewitt conducted an experimental trial that determined that exposure to light effectively treated jaundice in premature infants. The three researchers published their results in 'Prevention of Hyperbilirubinemia of Prematurity by Phototherapy' that same year in Pediatrics. Jaundice is the yellowing of the skin and eyes due to the failure of the liver to break down excess bilirubin in the blood, a condition called hyperbilirubinemia.

Format: Articles

Subject: Experiments

Gene Transfer Strategy Used to Treat Tay - Sachs Disease (2005), by Sabata Martino’s Research Group

By Tiffany Nardi

In the early 2000s, Sabata Martino and a team of researchers in Italy and Germany showed that they could reduce the symptoms of Tay-Sachs in afflicted mice by injecting them with a virus that infected their cells with a gene they lacked. Tay-Sachs disease is a fatal degenerative disorder that occurs in infants and causes rapid motor and mental impairment, leading to death at the ages of three to five. In gene therapy, researchers insert normal genes into cells that have missing or defective genes in order to correct genetic disorders.

Format: Articles

Subject: Experiments

The Effects of Gene Regulation on Aging in Caenorhabditis elegans (2003)

By Dasia Garcia

In 2003, molecular biology and genetics researchers Coleen T. Murphy, Steven A. McCarroll, Cornelia I. Bargmann, Andrew Fraser, Ravi S. Kamath, Julie Ahringer, Hao Li, and Cynthia Kenyon conducted an experiment that investigated the cellular aging in, Caenorhabditis elegans (C. elegans) nematodes. The researchers investigated the interactions between the transcription factor DAF-16 and the genes that regulate the production of an insulin-like growth factor 1 (IGF-1-like) protein related to the development, reproduction, and aging in C. elegans.

Format: Articles

Subject: Experiments

"The Limited In Vitro Lifetime of Human Diploid Cell Strains" (1964), by Leonard Hayflick

By Zane Bartlett

Leonard Hayflick in the US during the early 1960s showed that normal populations of embryonic cells divide a finite number of times. He published his results as 'The Limited In Vitro Lifetime of Human Diploid Cell Strains' in 1964. Hayflick performed the experiment with WI-38 fetal lung cells, named after the Wistar Institute, in Philadelphia, Pennsylvania, where Hayflick worked. Frank MacFarlane Burnet, later called the limit in capacity for cellular division the Hayflick Limit in 1974.

Format: Articles

Subject: Experiments

Barbara McClintock's Transposon Experiments in Maize (1931–1951)

By Federica Turriziani Colonna

Barbara McClintock conducted experiments on corn (Zea mays) in the United States in the mid-twentieth century to study the structure and function of the chromosomes in the cells. McClintock researched how genes combined in corn and proposed mechanisms for how those interactions are regulated. McClintock received the Nobel Prize in Physiology or Medicine in 1983, the first woman to win the prize without sharing it. McClintock won the award for her introduction of the concept of transposons, also called jumping genes.

Format: Articles

Subject: Experiments

Beadle and Tatum's 1941 Experiments with Neurospora Revealed that Genes Produce Enzymes

By Amy Pribadi

This illustration shows George Beadle and Edward Tatum's experiments with Neurospora crassa that indicated that single genes produce single enzymes. The pair conducted the experiments at Stanford University in Palo Alto, California. Enzymes are types of proteins that can catalyze reactions inside cells, reactions that produce a number of things, including nutrients that the cell needs. Neurospora crassa is a species of mold that grows on bread.

Format: Graphics

Subject: Theories, Experiments