Close your eyes and imagine Philadelphia in 1910. The soothing strains of Tchaikovsky’s Violin Concerto in D-major, Op. 35 emanate through the halls of a grand Victorian building, as chocolate rice pudding is being served for dessert. Have you started to imagine a tony dinner served by a tuxedoed staff? What if I said your dinner companions were a colony of rats? Specifically, Wistar rats—outbred albino rats developed for use in biomedical research and your dinner host is Dr. Helen Dean King, the first female scientist employed by The Wistar Institute. It is here, in this lab full of rats, that we encounter a moment of world-changing breakthroughs—genetic engineering, medical research, and the inclusion of women. 

Setting a Scientific Standard

Scientist Helen Dean King with her Wistar Rats, date unknown. | Image courtesy of The Wistar Institute

The ubiquity of rats in research today can be traced back to The Wistar Institute. When its third director, Milton J. Greenman, shifted the Institute’s focus away from comparison and classification towards a modern investigation of biological processes, developing a standardized laboratory animal became a key focus. Until this time, laboratories primarily utilized the common house mouse (Mus musculus). Greenman, along with neurophysiologist Henry H. Donaldson and biologist Helen Dean King, found the albino rat to be an ideal laboratory model as its nervous system develops in the same manner as humans, only exponentially faster. Rats share 90% of genes with humans, and their bodily systems perform in a similar manner. Almost all disease-linked human genes are thought to have an equivalent within the rat genome. Additionally, rats can be changed genetically, allowing scientists to turn “on” or “off” specific genes to determine how they might influence a particular disease. The genetically homogeneous and good-natured Wistar Rat was characterized by its wide head, long ears, and a tail always less than body length.

As early as 1912 The Wistar Institute sold stock from its rat colony, and by the mid-1930s it would become the world’s most widely used lab animal. This led to the WISTARAT trademark in 1942. By the 1960s, as the focus of the Institute continued to evolve, its rat breeding stocks were sold off along with the rights to the trademark, yet still more than half of the current albino strains used today, estimated at 117 types, are thought to derive from a single Wistar Rat. A quick Google search finds at least 14 different Wistar Rat suppliers across the globe, along with a proliferation of articles detailing the differences between the strains from each supplier.

Some estimate that rats and mice combined make up approximately 95% of all laboratory animals used today and are found in every field of research–from physiology, pharmacology, toxicology, nutrition, and behavior, among other fields of inquiry. As of 2009, PubMed data searches reveal that more than one-million publications have utilized rat research, which is the basis of more than 100 years of phenotyping experience. This knowledge base continues to make possible the cutting-edge advances in Alzheimer’s, Parkinson’s, HIV/AIDS, and more.

A Pioneering Woman of 20th Century Biology

Right: The Wistar Rat: a true Philadelphian. The outbred lab animal is one of the most popular rats used in science. Left: A bronze sculpture at The Wistar Institute commemorating their signature rat. | Photos: Janet Stephens, National Cancer Institute and The Wistar Institute

While the legacy of the Wistar Rat is tremendous, it should not overshadow the pioneering work of Helen Dean King whose success story should be shared and celebrated. Today we take for granted the inclusion of women in ground-breaking scientific and medical research, but up through the 1940s, the presence of women scientists bordered on the invisible. As The Wistar Institute’s first female scientist, King was no mere assistant to Greenman and Donaldson in the development, breeding, promotion, and distribution of the Wistar Rat.

To better understand King’s contributions one must look at the work of scholar Bonnie Tocher Clause, whose thorough assessment of The Wistar Institute archives provides great insight. Despite leaving nothing in the way of personal papers, Clause calls King an unsung hero of 20th century American biology. Within the Wistar archives lies the record of King’s long and productive career, including countless scientific publications, along with Director’s Reports and Board Minutes all written by King. It is here that Clause found a better understanding of King’s day-to-day work life, and her various research investigations, including collaborations within and outside of the Institute. Clause believes these documents allow us to infer a great deal about King’s professional relationships as a pioneer in a world occupied almost exclusively by men. These annual reports outline how King (and her colleagues) not only learned more about rat growth and development and the interplay of heredity and environment in variation, but also about rat husbandry and the fine points of breeding to achieve a desired result.

Helen Dean King was born in Owego, New York, the granddaughter of Reverend William H. King, who preached for temperance and abolition. After earning a B.A. from Vassar College in 1892, she moved to Philadelphia to attend Bryn Mawr College, the first college in the country to offer graduate degrees to women. At Bryn Mawr she became a prime example of dedication and independence. Within five years she had earned a Fellow in biology and two years later, her Ph.D. By 1906, she became a Fellow in Research Zoology at the University of Pennsylvania, specializing in genetics, researching inbreeding using rats. At the time King was the only woman to hold a professorship in research work other than Marie Curie in France. King was offered an Associate Professorship in Embryology at The Wistar Institute in 1909. Later she would serve as vice president of the American Society of Zoologists and associate editor of the Journal of Morphology and Physiology and the editor of The Wistar Institute’s bibliography service. In 1932, King was awarded the prestigious Ellen Richards Research prize, also known as the Women’s Nobel, by the Association to Aid Scientific Research by Women. Esteemed biologist, Edwin Grant, wrote a letter to the nominating committee on King’s behalf, stating “Dr. King has done the most important work in the biological sciences of any living woman.”

Yet, accolades as a female scientist notwithstanding, Bonnie Tocher Clause reminds us that King’s work is not mentioned, cited, nor included in the early histories of genetics. The legacy of the Wistar Rat is surely the legacy of Helen Dean King, whose name graces only one of the many extant strains of laboratory rats: King 1909. As Clause once wrote of King, “Surely the woman who holds responsibility for the creation of such durable experimental material warrants further scrutiny from the standpoint of genetics history.”