Embryo Project Encyclopedia

Edwin Carlyle Wood, also known as Carl Wood, was a physician who helped develop in vitro fertilization, or IVF, treatments. From 1964 to 1992, Wood worked as a professor of obstetrics and gynecology at Monash University in Melbourne, Australia, where he was one of the first in the world to lead a team of physicians to establish IVF as a proven treatment for infertility. IVF refers to a medical procedure in which scientists inseminate an egg cell with a sperm cell outside of the body, such as in a glass dish in a clinical setting. Wood helped establish some of the first successful IVF pregnancies and births, and his findings throughout his years of practice helped to standardize the procedure. Wood also advocated for the right for women to have an abortion, and co-founded the Family Planning Association of Victoria in Australia at a time when there were not many abortion clinics in operation. Through his early contributions to IVF, Wood provided new options for people to have offspring, which as of 2021, has up to a 21.3 percent chance of producing a live birth.

On 29 September 1973, researchers David De Kretzer, Peter Dennis, Bryan Hudson, John Leeton, Alexander Lopata, Ken Outch, James Talbot, and Carl Wood published “Transfer of a Human Zygote,” in The Lancet. In the article, the authors describe an experiment that resulted in one of the first pregnancies established via in vitro fertilization, or IVF. Prior to the article’s publication in 1973, there was no published evidence demonstrating whether IVF treatment would work in humans, although evidence existed showing that IVF worked in other mammals for breeding purposes. At the end of the article, the authors state that the embryo failed to implant into the wall of the patient’s uterus, leading to a miscarriage less than a week after the authors found evidence of pregnancy in the patient. The authors of “Transfer of a Human Zygote” were some of the first researchers to perform IVF, although unsuccessfully, which contributed to the overall understanding of IVF as an emerging technology.

In 1861, William John Little published, “On The Influence of Abnormal Parturition, Difficult Labors, Premature Birth, and Asphyxia Neonatorum, on the Mental and Physical Condition of the Child, Especially in Relation to Deformities,” hereafter “Abnormal Parturition,” in the Transactions of the Obstetrical Society of London. In the article, Little discussed the causes and types of what he refers to as abnormal births, and theorized how those births affect an infant’s likelihood of exhibiting a deformity. Little defined abnormal births as those involving an atypical maternal or fetal presentation, such as a slow birthing process or a fetus exiting the birth canal feet first rather than head first. In his article, Little published one of the first definitional frameworks to describe a condition causing rigidity and stiffness in the limbs that is often associated with birth-related trauma, which was then called Little’s disease, but is modernly known as spastic Cerebral Palsy.

The March of Dimes Foundation, or the March of Dimes, is a non-profit organization headquartered in Arlington, Virginia, focused on the health of pregnant women and infants in the US. Former United States president Franklin Delano Roosevelt founded the March of Dimes, then called the National Foundation for Infantile Paralysis, in 1938 to address polio. Polio is a viral illness that infects the spinal cord and may lead to paralysis. Roosevelt contracted polio in 1921, which left him permanently paralyzed from the waist down. During the 1960s, after scientists introduced polio vaccines, March of Dimes shifted its focus to prevent preterm birth and birth defects. As a non-profit organization, March of Dimes provides community service, funds for research, and efforts to educate the public about preterm birth and birth defects. While March of Dimes’ original goal was to help reduce the spread of polio in the US, it was also one of the first organizations to lead a campaign to prevent birth defects and infant mortality.

William John Little was one of the first orthopedic surgeons to research congenital malformations and their causes in the nineteenth century and presented preliminary research on a condition modernly known as cerebral palsy, a condition of varying severity that affects a person’s ability to move. Little worked throughout the United Kingdom for the majority of the time he practiced medicine, and eventually founded one of the first orthopedic infirmaries, the Royal Orthopedic Hospital in London, England. Throughout his career, Little studied congenital malformations, which are medical conditions inherited before birth, as well as how certain medical circumstances during delivery affect the neonate. In 1861, he described a condition with motor, behavioral, and cognitive irregularities in neonates, linked with oxygen deprivation during birth. Little’s research on that condition, originally called Little’s disease, and modernly, spastic cerebral palsy, was one of the first accounts of cerebral palsy in infants.

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. Interactions between epithelium and mesenchyme control the development and differentiation of many parts during embryonic development, including structures like the gastrointestinal tract and hair. Thus, the realization that mesenchyme drives induction and differentiation during epithelio-mesenchymal interactions had far-reaching effects.

In 1616 in Padua, Italy, Fortunio Liceti, a professor of natural philosophy and medicine, wrote and published the first edition of De Monstruorum Causis, Natura et Differentiis (On the Reasons, Nature, and Differences of Monsters), hereafter De monstruorum. In De monstruorum, Liceti chronologically documented cases of human and animal monsters from antiquity to the seventeenth century. During the seventeenth century, many people considered such monsters as frightening signs of evil cursed by spiritual or supernatural entities. Liceti categorized monsters based on their potential causes, several of which he claimed were unrelated to the supernatural. Historians later noted that some documented monsters were infants with birth defects. In De monstruorum, Liceti elevated the status of monsters to potential subjects of scientific inquiry and provided an early model for the study of birth defects, a field later called teratology.

Sir John Bertrand Gurdon further developed nuclear transplantation, the technique used to clone organisms and to create stem cells, while working in Britain in the second half of the twentieth century. Gurdon's research built on the work of Thomas King and Robert Briggs in the United States, who in 1952 published findings that indicated that scientists could take a nucleus from an early embryonic cell and successfully transfer it into an unfertilized and enucleated egg cell. Briggs and King also concluded that a nucleus taken from an adult cell and similarly inserted into an unfertilized enucleated egg cell could not produce normal development. In 1962, however, Gurdon published results that indicated otherwise. While Briggs and King worked with Rana pipiens frogs, Gurdon used the faster-growing species Xenopus laevis to show that nuclei from specialized cells still held the potential to be any cell despite its specialization. In 2012, the Nobel Prize Committee awarded Gurdon and Shinya Yamanaka its prize in physiology and medicine for for their work on cloning and pluripotent stem cells.

Mesoderm is one of the three germ layers, groups of cells that interact early during the embryonic life of animals and from which organs and tissues form. As organs form, a process called organogenesis, mesoderm interacts with endoderm and ectoderm to give rise to the digestive tract, the heart and skeletal muscles, red blood cells, and the tubules of the kidneys, as well as a type of connective tissue called mesenchyme. All animals that have only one plane of symmetry through the body, called bilateral symmetry, form three germ layers. Animals that have only two germ layers develop open digestive cavities. In contrast, the evolutionary development of the mesoderm allowed in animals the formation of internal organs such as stomachs and intestines (viscera).

The Spemann-Mangold organizer, also known as the Spemann organizer, is a cluster of cells in the developing embryo of an amphibian that induces development of the central nervous system. Hilde Mangold was a PhD candidate who conducted the organizer experiment in 1921 under the direction of her graduate advisor, Hans Spemann, at the University of Freiburg in Freiburg, German. The discovery of the Spemann-Mangold organizer introduced the concept of induction in embryonic development. Now integral to the field of developmental biology, induction is the process by which the identity of certain cells influences the developmental fate of surrounding cells. Spemann received the Nobel Prize in Medicine in 1935 for his work in describing the process of induction in amphibians. The Spemann-Mangold organizer drew the attention of embryologists, and it spurred numerous experiments on the nature of induction in many types of developing embryos.