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Ernest Everett Just

Contributed by Aaron Slater

Researcher’s Background

Ernest Everett Just was an early 20th century African American embryologist that had a profound interest in fertilization and egg development processes of marine invertebrates.

Biography in brief

Just started his academic endeavors attending Dartmouth College, afterwards joining the faculty of Howard University. During his summers he worked at the Marine Biological Laboratory in Woods Hole, Massachusetts. There he was able to expand his knowledge by studying marine species in lab and in their aquatic habitats. He published many scientific articles and has been acknowledged in many research societies for his noteworthy experimental embryology studies propelling our understanding in marine biology.

Is (or was) their research under-valued because of their identity?

Yes

It was harder to do good research in the states during his time because of institutionalized racism which set limits on his behalf. Just found more opportunity in Europe.

Are there other scientists/research examples that this example can replace or be added to?

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How do fertilization envelopes form?

Contributed by Aaron Slater

Research Overview

Take home message of the research:

Just studied various species to understand how marine invertebrates developed over time. While at Woods Hole research station he had the opportunity to explore parthenogenesis in eggs of marine animals. Parthenogenesis is the process of a female making a viable egg that grows into an adult without the fertilization from a male.

Just focused his research on the events of egg cell transformations following initial sperm-egg interaction. These fertilization envelopes called vitelline envelopes is an extracellular fibrous layer on the outside of an embryo in non-mammalian species to help protect the egg through its development. The fertilization envelope changes over time allowing for a greater understanding of developmental biology. Two marine related species studied by Just was Echinarachnius parma (the common sand dollar) and Chaetopterus pergamentaceus (the parchment worm).

Study system

Photographs of marine invertebrates Just studied. Source: Byrnes and Eckberg 2006

(A) Echinarachnius parma (sand dollar)

(B) Chaetopterus pergamentaceus (parchment worm)

(C) Platynereis dumerilii (nereid worm)

(D) Arbacia punctulata (sea urchin)

(E) Nereis limbata (clam worm)

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How do fertilization envelopes form?

Contributed by Aaron Slater