12.6: Scientist Spotlight - Ernest Everett Just

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For those who enjoy them sunny side up, scrambled, or hard boiled, the word “egg” may bring chickens to mind. However, eggs don’t always take the form of smooth, oval-shaped objects that constitute your breakfast, nor do they only come from birds. Scientifically speaking, an “egg” is a gamete, or a sex cell, central to the process of sexual reproduction. This means that eggs are common to all sexually reproducing organisms, even the ones that don’t lay the eggs we’re familiar with.

One type of reproduction, called sexual reproduction, occurs when a sperm cell fertilizes an egg cell. The fertilized egg cell is called a “zygote”. When two organisms are involved, the zygote contains genetic material from two different parents. However, sexual reproduction can also occur when one hermaphroditic organism (possessing male and female gametes) self-fertilizes. No matter the number of contributors, the defining mechanism of sexual reproduction is when a sperm cell fertilizes an egg cell. This process occurs on a microscopic level, so how do we know what fertilization looks like? One answer to this broad question was unearthed by embryologist Ernest Everett Just. Just was born in Charleston, South Carolina in 1883, and his father died 4 years later (Selassie 2007). He went on to graduate from Dartmouth College, teach English and biology at Howard University, and earn a PhD in zoology at the University of Chicago (Byrnes and Newman 2014). Prior to his time in Chicago, Just conducted research at the Woods Hole Biological Marine Laboratory, where his work with marine invertebrates revealed that the ectoplasm (egg surface) significantly influences the fertilization and development of eggs (Just 1919, 1922; Wellner 2010).

Throughout his career, Just authored more than seventy papers and two books. Despite his major contributions to our understanding of fertilization and evolutionary developmental biology, his work was “...largely forgotten and invisible to the world of biology” (Byrnes and Newman 2014). As an African American man in the early 20th century, Just belonged to a historically marginalized group of people, and he is only now receiving recognition for his pioneering work.

A man wearing a suit and tie looks toward the viewer of this portrait.

Figure \(\PageIndex{1}\): "Ernest Everett Just" is in the Public Domain.

References

Scientist Spotlight Inspiration from the Scientist Spotlights Initiative

Byrnes, M.W., & Newman, S.A. (2014). Ernest Everett Just: Egg and embryo as excitable systems. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4277254/>. Accessed October 5, 2021.

Just, Ernest Everett. 1919. The Fertilization Reaction in Echinarachnius Parma. Biological Bulletin, 36(1), pp. 1-10.

Just, Ernest Everett. 1922. Initiation of development in the egg of Arbacia. II. Fertilization of eggs in various stages of artificially induced mitosis. Biological Bulletin, 43(6), pp. 401-410.

Selassie I, & Gabriel, W. (2007). Ernest Everett Just (1883-1941). <https://www.blackpast.org/african-am...ett-1883-1941/>. Accessed October 5, 2021.

Wellner, K. (2010). Ernest Everett Just (1883-1941). Embryo Project Encyclopedia. <http://embryo.asu.edu/handle/10776/2039>. Accessed October 5, 2021.