Search

Displaying 426 - 450 of 585 items.

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

"Reproductive Options for HIV-Serodiscordant Couples” (2006) by Pablo Barreiro, Ann Duerr, Karen Beckerman, and Vincent Soriano

In July 2006, scientist Pablo Barreiro and colleagues published “Reproduction Options for HIV-Serodiscordant Couples,” in which they recommended methods for human immunodeficiency virus, or HIV, serodiscordant couples to procreate. An HIV-serodiscordant couple is one in which one partner is HIV-positive, meaning they carry HIV, and the other is HIV-negative, meaning they do not carry the virus. HIV is a virus that can spread by sexual contact and it attacks the immune system, causing a person with the virus to have weakened responses to illnesses.

Format: Articles

Subject: Publications

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

Barbara McClintock (1902-1992)

Barbara McClintock worked on genetics in corn (maize) plants and spent most of her life conducting research at the Cold Spring Harbor Laboratory in Laurel Hollow, New York. McClintock's research focused on reproduction and mutations in maize, and described the phenomenon of genetic crossover in chromosomes. Through her maize mutation experiments, McClintock observed transposons, or mobile elements of genes within the chromosome, which jump around the genome. McClintock received the Nobel Prize for Physiology or Medicine in 1983 for her research on chromosome transposition.

Format: Articles

Subject: People

"Evolution and Tinkering" (1977), by Francois Jacob

In his essay Evolution and Tinkering, published in
Science in 1977, Francois Jacob argued that a common analogy
between the process of evolution by natural selection and the
methods of engineering is problematic. Instead, he proposed to
describe the process of evolution with the concept of
bricolage (tinkering). In this essay, Jacob did not deny the
importance of the mechanism of natural selection in shaping complex
adaptations. Instead, he maintained that the cumulative effects of

Format: Articles

Subject: Publications, Theories

Photograph 51, by Rosalind Franklin (1952)

On 6 May 1952, at King’s College London in London, England, Rosalind Franklin photographed her fifty-first X-ray diffraction pattern of deoxyribosenucleic acid, or DNA. Photograph 51, or Photo 51, revealed information about DNA’s three-dimensional structure by displaying the way a beam of X-rays scattered off a pure fiber of DNA. Franklin took Photo 51 after scientists confirmed that DNA contained genes. Maurice Wilkins, Franklin’s colleague showed James and Francis Crick Photo 51 without Franklin’s knowledge. Watson and Crick used that image to develop their structural model of DNA.

Format: Articles

Subject: Publications

Johannes Holtfreter (1901-1992)

Johannes Holtfreter made important discoveries about the properties of the organizer discovered by Hans Spemann. Although he spent much time away from the lab over many years, he was a productive researcher. His colleagues noted that the time he spent away helped revitalize his ideas. He is credited with the development of a balanced salt medium to allow embryos to develop; the discovery that dead organizer tissue retains inductive abilities; and the development of specification, competence, and distribution of fate maps in the developing frog embryo.

Format: Articles

Subject: People

Multi-Fetal Pregnancy

In humans, multi-fetal pregnancy occurs when a mother carries more than one fetus during the pregnancy. The most common multi-fetal pregnancy is twins, but mothers have given birth to up to eight children (octuplets) from a single pregnancy. Multiple fetusus can result from the release of multiple eggs or multiple ovulations, the splitting of a single fertilized egg, and fertility treatments such as in vitro fertilization (IVF) which involves the insertion of many fertilized eggs into the mother's uterus.

Format: Articles

Subject: Processes, Reproduction

Florence Rena Sabin (1871-1953)

Florence Rena Sabin had successful careers as both a researcher and public health reformer. When Johns Hopkins University Medical School opened, accepting women and men on the same basis, Sabin was one of the first to enter. After the successful completion of her MD degree, Sabin went on to become the first female faculty member and later full-time professor at Johns Hopkins.

Format: Articles

Subject: People

August Antonius Rauber (1841-1917)

August Antonius Rauber was an embryologist and anatomist who examined gastrulation in avian embryos. He examined the formation of the blastopore, epiblast, and primitive streak during chick development. Subsequent researchers have further studied Rauber's findings, which has led to new discoveries in embryology and developmental biology.

Format: Articles

Subject: People

Thomas Henry Huxley (1825-1895)

In nineteenth century Great Britain, Thomas Henry Huxley proposed connections between the development of organisms and their evolutionary histories, critiqued previously held concepts of homology, and promoted Charles Darwin's theory of evolution. Many called him Darwin's Bulldog. Huxley helped professionalize and redefine British science. He wrote about philosophy, religion, and social issues, and researched and theorized in many biological fields.

Format: Articles

Subject: People

Sperm Capacitation

Sperm capacitation refers to the physiological changes spermatozoa must undergo in order to have the ability to penetrate and fertilize an egg. This term was first coined in 1952 by Colin Russell Austin based on independent studies conducted by both Austin himself as well as Min Chueh Chang in 1951. Since the initial reports and emergence of the term, the details of the process have been more clearly elucidated due to technological advancements.

Format: Articles

Subject: Processes

"Genetic Control of Biochemical Reactions in Neurospora" (1941), by George W. Beadle and Edward L. Tatum

George Wells Beadle and Edward Lawrie Tatum's 1941 article Genetic Control of Biochemical Reactions in Neurospora detailed their experiments on how genes regulated chemical reactions, and how the chemical reactions in turn affected development in the organism. Beadle and Tatum experimented on Neurospora, a type of bread mold, and they concluded that mutations to genes affected the enzymes of organisms, a result that biologists later generalized to proteins, not just enzymes.

Format: Articles

Subject: Experiments

The Baby Makers (2012)

In 2012, the production company Waddell Media Production released the documentary The Baby Makers. The four-part series, directed and produced by Edel O’Mahony, follows multiple couples in Northern Ireland struggling with infertility problems as they utilize different treatments such as in vitro fertilization, or IVF, egg donation, and egg freezing. IVF is a procedure in which a woman’s egg is fertilized by a sperm outside of her body. Once the sperm fertilizes the egg, a fertility doctor places the fertilized egg back into the woman’s uterus.

Format: Articles

Subject: Outreach

Hydrocephalus During Infancy

Hydrocephalus is a congenital or acquired disorder characterized by the abnormal accumulation of cerebrospinal fluid within the cavities of the brain, called ventricles. The accumulation of cerebrospinal fluid, the clear fluid surrounding the brain and spinal cord, causes an abnormal widening of the ventricles. The widening creates potentially harmful pressure on the tissues of the brain that can result in brain damage or death.

Format: Articles

Subject: Disorders

Betty Friedan (1921–2006)

Betty Friedan advocated for the advancement of women's rights in the twentieth century in the United States. In 1963, Friedan wrote The Feminine Mystique, which historians consider a major contribution to the feminist movement. Friedan also helped establish two organizations that advocated for women's right, the National Organization for Women (NOW) in 1963 and, in 1969 the National Association for the Repeal of Abortion Laws (NAARL). Friedan argued for legalizing access to abortion and contraception, and her advocacy helped advance women's reproductive rights.

Format: Articles

Subject: People

Early Infantile Autism and the Refrigerator Mother Theory (1943-1970)

In 1943, child psychiatrist Leo Kanner in the US gave the first account of Early Infantile Autism that encouraged psychiatrists to investigate what they called emotionally cold mothers, or refrigerator mothers. In 1949, Kanner published Problems of Nosology and Psychodynamics of Early Infantile Autism. In that article, Kanner described autistic children as reared in emotional refrigerators. US child psychiatrists claimed that some psychological or behavioral conditions might have origins in emotional or mental stress, meaning that they might be psychogenic.

Format: Articles

Subject: Disorders, Theories

Gattaca (1997)

Gattaca is a 1997 science fiction film produced in the US that depicts a future society that uses reproductive technology and genetic engineering in order to produce genetically enhanced human beings. By selectively choosing certain genes, scientists and physicians ensure that individuals born using reproductive technologies have desirable physical and psychological traits and prevent undesirable traits.

Format: Articles

Subject: Publications

Retinoids As Teratogens

Vitamin A (retinol) is an essential vitamin in the daily functioning of human beings that helps regulate cellular differentiation of epithelial tissue. Studies have shown that an excess of vitamin A can affect embryonic development and result in teratogenesis, or the production of birth defects in a developing embryo. Excess intake of vitamin A and retinoids by pregnant women often results malformations to fetuses' skulls, faces, limbs, eyes, central nervous system.

Format: Articles

Subject: Disorders, Reproduction

Congenital Vertebral Defects

The spinal column is the central structure in the vertebrate body from which stability, movement, and posture all derive. The vertebrae of the spine are organized into four regions (listed in order from cranial to caudal): cervical, thoracic, lumbar, and pelvic. These regions are classified by their differences in curvature. The human spine usually consists of thirty-three vertebrae, seven of which are cervical (C1-C7), twelve are thoracic (T1-T12), five are lumbar (L1-L5), and nine are pelvic (five fused as the sacrum and four fused as the coccyx).

Format: Articles

Subject: Disorders, Reproduction

Landrum Brewer Shettles (1909-2003)

Landrum Brewer Shettles is remembered as an important contributor to early in vitro fertilization research in the United States as well as a prolific author on the subject of choosing a child's sex before conception. Shettles was born in Pontotoc County, Mississippi on 21 November 1909 to Sue Mounce and Brazil Manly. Shettles trained and worked as a gynecologist at Columbia University Presbyterian Medical Center, after receiving his MD in 1943 from Johns Hopkins University.

Format: Articles

Subject: People, Reproduction

John Tyler Bonner (1920- )

The establishment and growth of developmental-evolutionary biology owes a great debt to the work of John Tyler Bonner. Bonner's studies of cellular slime molds have shed light on some of the big questions of biology including the origins of multicellularity and the nature of morphogenesis. The second child of Lilly Marguerite Stehli and Paul Bonner, John Tyler was born 12 May 1920 in New York City and spent his early years in Locust Valley, Long Island (late 1920s), France (1930), and London (1932).

Format: Articles

Subject: People

George McDonald Church (1954- )

George McDonald Church studied DNA from living and from extinct species in the US during the twentieth and twenty-first centuries. Church helped to develop and refine techniques with which to describe the complete sequence of all the DNA nucleotides in an organism's genome, techniques such as multiplex sequencing, polony sequencing, and nanopore sequencing. Church also contributed to the Human Genome Project, and in 2005 he helped start a company, the Personal Genome Project. Church proposed to use DNA from extinct species to clone and breed new organisms from those species.

Format: Articles

Subject: People

Paul Kammerer's Experiments on Sea-squirts in the Early Twentieth Century

In the early twentieth century, Paul Kammerer, a zoologist working at the Vivarium in Vienna, Austria, experimented on sea-squirts (Ciona intestinalis). Kammerer claimed that results from his experiments demonstrated that organisms could transmit characteristics that they had acquired in their lifetimes to their offspring. Kammerer conducted breeding experiments on sea-squirts and other organisms at a time when Charles Darwin's 1859 theory of evolution lacked evidence to explain how offspring inherited traits from their parents.

Format: Articles

Subject: Experiments, Organisms