Cassandra G. Extavour

Cassandra Extavour is a Canadian geneticist, researcher of organismic and evolutionary biology, professor of molecular and cell biology at Harvard University, and a classical singer. Her research has focused on evolutionary and developmental genetics. She is known for demonstrating that germ cells engage in cell to cell competition before becoming a gamete, which indicates that natural selection can affect and change genetic material before adult sex reproduction takes place. She was also the director of EDEN (the Evo-Devo-Eco Network), a National Science Foundation-funded research collaborative that encouraged scientists working on organisms other than the standard lab model organisms to share protocols and techniques.

Extavour didn't realize she had a knack for science until high school. She did well in her math and science classes and that led her to consider a career in science when she had only ever thought of being a musician or a baker.

Science career Extavour received an Honors BSc at the University of Toronto. Her Ph.D. thesis under Antonio García-Bellido was on germ cell selection in genetic mosaics and was published in 2001 in PNAS.

In 2003 Extavour conducted a study at Cambridge University on the mechanisms of germ cell formation that showed animal germ cells were likely specified by inductive signals more often than previously thought. This went against the mainstream scientific view that animal germ cells are usually specified by maternally inherited determinants. During a 2013 interview with Quanta Magazine, she explained the concepts of this research as such: "Before there is even an embryo, the molecular content of some cells predetermines them to develop as either germ or soma. In other organisms, there is instead a signaling mechanism: An embryonic cell receives chemical signals from neighboring cells that activate (or repress) the genes that allow for germ-line function." Extavour and her colleagues were able to specify that two BMPs, BMP8b and BMP4, help induce PGCs in this insect. This is significant because it was the first demonstration of a specific signaling pathway operating in the induction of embryonic germ cells in an Invertebrate.

From 2010 to 2015 Extavour directed a national research collaborative called EDEN, which stands for Evo-Devo-Eco (evolutionary-developmental-ecological) Network. The organization, funded by the National Science Foundation, encouraged scientists to develop and share tools and techniques for use in a broader spectrum of organisms than the traditionally studied laboratory model organisms. Ellison Medical Foundation New Scholar in Aging Award

Music Extavour sings Classical and Baroque music professionally. She has a soprano voice and pursues her musical career part-time, while being a scientist full-time. She sings in the Handel and Haydn Society chorus in Boston.

Publications Her most highly cited publications are:

Extavour, CG, M Akam "Mechanisms of germ cell specification across the metazoans: epigenesis and preformation" Development 2004 Dec125, 130 (24) 589-840 According to Google Scholar, this publication has been cited 649 times as of June 27, 2020. Ewen-Campen, Evelyn E Schwager, and Cassandra GM Extavour, The molecular machinery of germ line specification Molecular and Cellular Reproduction. Volume 77, Issue 1, pages 3–18, January 2010. According to Google Scholar, this publication has been cited 139 times as of June 27, 2020.