John W. Saunders, Jr.

John W. Saunders Jr. (November 12, 1919 – December 26, 2015) was an American scientist whose research in the field of developmental biology and zoology played an integral part in helping to understand how limbs develop in vertebrates. Saunders researched the vertebrate limb and studied the apical ectodermal ridge (AER). This research was critical for identifying growth factors secreted from the AER and what role these factors play in assisting the pattern of vertebrate limb development.

Personal life John W. Saunders Jr. was born in Muskogee, Oklahoma, on November 12, 1919. He gave the money he earned to his family in order to help support them and he kept this job throughout high school. They were married for 69 years and had five children. Additionally, he also had a sister named Virginia Lavarine. Saunders spent the summer of 1954 doing research at the Mount Desert Island (MDI) Biological Laboratory, located in Salisbury Cove, Maine.

Research Saunders is most notable for his research concerning the apical ectodermal ridge (AER), which he studied for over 50 years. In his 1948 publication "The proximo-distal sequence of origin of the parts of the chick wing and the role of the ectoderm", Saunders first suggested that the apical ectoderm may potentially influence the areas involved in wing development of chicks. In this study, the apical ectoderms of wing buds were removed at various stages (stages 4–7) of wing development.

Saunders continued to study the AER and followed up his early work with more research on the apical zone as well as its role in the formation of wing limbs in chick embryos. In 1962, Saunders published an article titled "On the role of ectoderm in limb development" in which he made several promising conclusions. He concluded that when EDTA is used to remove the ectoderm from limb buds, regions towards the end of the limb do not form. However, he also found that, even in the absence of the apical ridge, limb buds with remaining ectodermal cells present after treatment with EDTA could still develop in their distal regions. Ultimately, this leads to the growth of the end-regions of the limb. In a 1962 publication, co-authored by Saunders, titled "Cellular death in morphogenesis of the avian wing", Saunders helped indicate posterior regions of the wing where many cells degenerated, and they termed this region the posterior necrotic zone (PNZ). From this, he showed that some cases of cell death during embryonic development have useful purposes and that the death of cells can be controlled by certain cellular and humoral aspects of the environment. He made this inference based on the conclusion that the AER transfers developmental information by means of signal induction in a manner that remains constant between the various stages and levels that the bud goes through in its development. In this publication, the researchers identified a posterior zone of specialized cells present in the initial stages of embryotic avian development which was called the zone of polarizing activity (ZPA). He also observed the ability of dissociated cells of the AER to change the layout at the mesodermal apex in a normal AER. According to this article, Saunders and Feinberg removed the AER of chick embryos during stages 17–23 of their development. After this, they observed how the vascular pattern during the development of the marginal vein of the chick embryos was affected by the removal of the AER.

Honors and awards While studying at the University of Oklahoma in 1936, Saunders was a member of the Phi Beta Kappa academic honor society. During the early years of his career, he also became a member of the American Association for the Advancement of Science in 1946. He also became a member of the American Society of Zoologists (now called the Society for Integrative and Comparative Biology) in 1948 and served as program officer (1959-1962), membership committee chairman (1959-1960), chair of the developmental biology division (1963), and secretary (1964-1966). In 1950, Saunders became a member of the Wisconsin Academy of Sciences, Arts, and Letters. Saunders also became a member of corporation of the Mount Desert Island Biological Laboratory in 1954 and remained one until 1983. In 1957, he became a member of the International Society of Developmental Biologists and the American Institute of Biological Sciences. The following year in 1958, he also became a member of the New York Academy of Sciences. A year later, he became a member of corporation of the Marine Biological Laboratory (MBL) in 1959, and he served on the MBL's board of trustees from 1969 to 1972. Saunders was also a member of the American Society for Cell Biology (1960) as well as the Society for Experimental Biology and Medicine (1964). A few years later in 1966, he became a member of the Society for Developmental Biology (SDB), and he served on the SDB's executive committee (1967-1969) and was president of the organization for a year (1968). In 1969, Saunders also became a member of the Association for the Advancement of Ageing Research and was a council member for this association from 1969 to 1970. In 1996, he was awarded the Edwin Grant Conklin Medal by the American Society of Developmental Biology. Ten years later, he was elected to the National Academy of Sciences (2006), and he received the University of Oklahoma College of Arts and Sciences Distinguished Alumni Award the subsequent year in 2007. Saunders is also an emeritus of the American Association of Anatomists.