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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

Effects of Prenatal Alcohol Exposure on Cerebellum Development

Prenatal exposure to alcohol (ethanol) results in a continuum of physical, neurological, behavioral, and learning defects collectively grouped under the heading fetal alcohol spectrum disorders (FASD). Fetal alcohol syndrome (FAS) is the most severe combination of these defects under this heading, and is characterized by pre- and postnatal growth deficiencies, facial abnormalities, and defects of the central nervous system (CNS).

Format: Articles

Subject: Disorders, Reproduction

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

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

California Proposition 71 (2004)

The California Stem Cell Research and Cures Act, also called Proposition 71, was a ballot
initiative proposed by California voters in 2004 to allocate three billion dollars of state
funds for stem cell research over ten years. Endorsed by California scientists and
patient-advocates, Prop 71 passed on 2 November 2004, amending the state constitution to make
stem cell research a constitutional right. In addition, Prop 71 led to the creation of the
California Institute for Regenerative Medicine (CIRM), in San Francisco, California to allocate

Format: Articles

Subject: Legal

Effects of Prenatal Alcohol Exposure on Central Nervous System Development

Prenatal exposure to alcohol (ethanol) results in a continuum of physical, neurological, behavioral, and learning defects collectively grouped under the heading Fetal Alcohol Spectrum Disorder (FASD). Fetal Alcohol Syndrome (FAS) is part of this group and was first defined in 1973 as a condition characterized by pre- and postnatal growth deficiencies, facial abnormalities and defects of the central nervous system (CNS). The CNS is particularly vulnerable to the effects of ethanol during prenatal development.

Format: Articles

Subject: Disorders, Reproduction

Roy John Britten (1919-2012)

Roy John Britten studied DNA sequences in the US in the second
half of the twentieth century, and he helped discover repetitive
elements in DNA sequences. Additionally, Britten helped propose
models and concepts of gene regulatory networks. Britten studied the
organization of repetitive elements and, analyzing data from the
Human Genome Project, he found that the repetitive elements in DNA
segments do not code for proteins, enzymes, or cellular parts.
Britten hypothesized that repetitive elements helped cause cells to

Format: Articles

Subject: People

San Diego Zoo Institute for Conservation Research

The San Diego Zoo Institute for Conservation Research (SDZICR) in San Diego, California, is a research organization that works to generate, use, and share information for the conservation of wildlife and their habitats. In 1975, Kurt Benirschke, a researcher at the University of California, San Diego (UCSD) who studied human and animal reproduction, and Charles Bieler, the director of the San Diego Zoo, collaborated to form the Center for Reproduction of Endangered Species (CRES).

Format: Articles

Subject: Organizations

Facial Abnormalities of Fetal Alcohol Syndrome (FAS)

Prenatal exposure to alcohol (ethanol) results in a continuum of physical, neurological, behavioral, and learning defects collectively grouped under the heading Fetal Alcohol Spectrum Disorder (FASD). Fetal Alcohol Syndrome (FAS) was first defined in 1973 as a condition characterized by pre- and postnatal growth deficiencies, facial abnormalities, and defects of the central nervous system. The pattern of facial defects that occur as a result of ethanol exposure during development primarily affects the midline of the face, altering morphology of the eyes, nose, and lips.

Format: Articles

Subject: Disorders, Reproduction

The Cell in Development and Inheritance (1900), by Edmund Beecher Wilson

The Cell in Development and Inheritance, by Edmund Beecher Wilson, provided a textbook introduction to cell biology for generations of biologists in the twentieth century. In his book, Wilson integrated information about development, inheritance, chromosomes, organelles, and the structure and functions of cells. First published in 1896, the book started with 371 pages, grew to 483 pages in the second edition that appeared in 1900, and expanded to 1,231 pages by the third and final edition in 1925.

Format: Articles

Subject: Publications

Somatic Cell Nuclear Transfer in Mammals (1938-2013)

In the second half of the
twentieth century, scientists learned how to clone organisms in some
species of mammals. Scientists have applied somatic cell nuclear transfer to clone human and
mammalian embryos as a means to produce stem cells for laboratory
and medical use. Somatic cell nuclear transfer (SCNT) is a technology applied in cloning, stem cell
research and regenerative medicine. Somatic cells are cells that
have gone through the differentiation process and are not germ
cells. Somatic cells donate their nuclei, which scientists

Format: Articles

Subject: Theories, Technologies, Processes

"Cellular death in morphogenesis of the avian wing" (1962), by John W. Saunders Jr., et al.

In the early 1960s, John W. Saunders Jr., Mary T. Gasseling, and Lilyan C. Saunders in the US investigated how cells die in the developing limbs of chick embryos. They studied when and where in developing limbs many cells die, and they studied the functions of cell death in wing development. At a time when only a few developmental biologists studied cell death, or apoptosis, Saunders and his colleagues showed that researchers could use embryological experiments to uncover the causal mechanisms of apotosis.

Format: Articles

Subject: Experiments

Nuclear Transplantation

Nuclear transplantation is a method in which the nucleus of a donor cell is relocated to a target cell that has had its nucleus removed (enucleated). Nuclear transplantation has allowed experimental embryologists to manipulate the development of an organism and to study the potential of the nucleus to direct development. Nuclear transplantation, as it was first called, was later referred to as somatic nuclear transfer or cloning.

Format: Articles

Subject: Processes

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

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.

Format: Articles

Subject: Experiments

"Induction and Patterning of the Primitive Streak, an Organizing Center of Gastrulation in the Amniote" (2004), by Takashi Mikawa, Alisa M. Poh, Kristine A. Kelly, Yasuo Ishii, and David E. Reese

"Induction and Patterning of the Primitive Streak, an Organizing Center of Gastrulation in the Amniote," (hereafter referred to as "Induction") examines the mechanisms underlying early amniote gastrulation and the formation of the primitive streak and midline axis. The review, authored by Takashi Mikawa and colleagues at Cornell University Medical College, was published in Developmental Dynamics in 2004.

Format: Articles

Subject: Publications

Sex-determining Region Y in Mammals

The Sex-determining Region Y (Sry in mammals but SRY in humans) is a gene found on Y chromosomes that leads to the development of male phenotypes, such as testes. The Sry gene, located on the short branch of the Y chromosome, initiates male embryonic development in the XY sex determination system. The Sry gene follows the central dogma of molecular biology; the DNA encoding the gene is transcribed into messenger RNA, which then produces a single Sry protein.

Format: Articles

Subject: Processes

"Gene Regulation for Higher Cells: A Theory" (1969), by Roy J. Britten and Eric H. Davidson

In 1969, Roy J. Britten and Eric H. Davidson published Gene Regulation for Higher Cells: A Theory, in Science. A Theory proposes a minimal model of gene regulation, in which various types of genes interact to control the differentiation of cells through differential gene expression. Britten worked at the Carnegie Institute of Washington in Washington, D.C., while Davidson worked at the California Institute of Technology in Pasadena, California. Their paper was an early theoretical and mechanistic description of gene regulation in higher organisms.

Format: Articles

Subject: Publications

Alejandro Sánchez Alvarado (1964- )

Alejandro Sánchez Alvarado is a Professor of Neurobiology and Anatomy at the University of Utah School of Medicine and is also a Howard Hughes Medical Institute Investigator. Born in Caracas, Venezuela, 24 February 1964, Sánchez Alvarado left his home to pursue education in the United States, where he received a Bachelor of Science in molecular biology and chemistry from Vanderbilt University in 1986 and a Doctorate in pharmacology and cell biophysics at the University of Cincinnati College of Medicine in 1992.

Format: Articles

Subject: People

Effects of Prenatal Alcohol Exposure on Cardiac Development

A variety of developmental defects occur as a result of prenatal exposure to alcohol (ethanol) in utero. In humans, those defects are collectively classified as Fetal Alcohol Spectrum Disorders, with Fetal Alcohol Syndrome (FAS) representing the more severe defects. FAS is defined by pre- and post-natal growth retardation, minor facial abnormalities, and deficiencies in the central nervous system (CNS). In addition to those defects, prenatal exposure to alcohol impacts cardiogenesis, the developmental stage of heart formation.

Format: Articles

Subject: Disorders, Reproduction

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

Ernest John Christopher Polge (1926-2006)

Twentieth-century researcher Ernest John Christopher Polge studied the reproductive processes of livestock and determined a method to successfully freeze, thaw, and utilize viable sperm cells to produce offspring in animals. In 1949, Polge identified glycerol as a cryoprotectant, or a medium that enables cells to freeze without damaging their cellular components or functions. Several years later, Polge used glycerol in a freezing process called vitrification, which enabled him to freeze poultry sperm, thaw that sperm, and use it to fertilize vertebrate embryos.

Format: Articles

Subject: People

Morphogenesis

The term morphogenesis generally refers to the processes by which order is created in the developing organism. This order is achieved as differentiated cells carefully organize into tissues, organs, organ systems, and ultimately the organism as a whole. Questions centered on morphogenesis have aimed to uncover the mechanisms responsible for this organization, and developmental biology textbooks have identified morphogenesis as one of the main challenges in the field. The concept of morphogenesis is intertwined with those of differentiation, growth, and reproduction.

Format: Articles

Subject: Processes

Slime mold development video by John Tyler Bonner

This video is composed of a sequence of time lapse films created by John Tyler Bonner in the 1940s to show the life cycle of the cellular slime mold, Dictyostelium discoideum. As only the second person to study slime molds, Bonner frequently encountered audiences who had never heard of, let alone seen, the unusual organism. He therefore decided to create a film to present at seminars in order to introduce his object of study. Bonner created the video for his senior thesis at Harvard University with the help of photographer Frank Smith.

Format: Video

Subject: Organisms

Leonard Hayflick (1928- )

Leonard Hayflick studied the processes by which cells age during the twentieth and twenty-first centuries in the United States. In 1961 at the Wistar Institute in the US, Hayflick researched a phenomenon later called the Hayflick Limit, or the claim that normal human cells can only divide forty to sixty times before they cannot divide any further. Researchers later found that the cause of the Hayflick Limit is the shortening of telomeres, or portions of DNA at the ends of chromosomes that slowly degrade as cells replicate.

Format: Articles

Subject: People

"Sheep Cloned by Nuclear Transfer from a Cultured Cell Line" (1996), by Keith Campbell, Jim McWhir, William Ritchie, and Ian Wilmut

In 1995 and 1996, researchers at the Roslin Institute in Edinburgh, Scotland, cloned mammals for the first time. Keith Campbell, Jim McWhir, William Ritchie, and Ian Wilmut cloned two sheep, Megan and Morag, using sheep embryo cells. The experiments indicated how to reprogram nuclei from differentiated cells to produce live offspring, and that a single population of differentiated cells could produce multiple offspring. They reported their results in the article 'Sheep Cloned by Nuclear Transfer from a Cultured Cell Line' in March 1996.

Format: Articles

Subject: Experiments

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