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Form from the Formless: The Awesome Power of the Embryo

Hazel Sive: March 21, 2005; Running Time: 1:01:52

About the Lecture

About the Lecture

How does a single cell become a complex organism? The fascination and challenge of this question, says Hazel Sive, “drives me out of bed each day, makes me work long hours and keeps me excited about coming here.” Sive’s Whitehead lab investigates developing embryos for clues about how cells organize and form tissues and organs. Not only must an embryo determine what kinds of cells to grow, it must also place them in precise patterns, along three dimensions. As the embryo develops, cells signal to each other to move to a specific position, or a regulatory protein sends a command for a cell to align itself in a certain way. Sive’s particularly interested in the evolution of brain structure. Zebrafish serve as her model. The tiny, transparent embryos of this fish enable her to “look directly into the brain in a noninvasive way.” Sive plays a video showing how a brain forms from a sheet of cells that first rolls up into a tube. Then, three distinct areas emerge that correspond to key neural functions. If a gene responsible for this patterning of early brain structure goes awry, then the zebra fish embryo may emerge with a brain cavity that’s too big or too small to permit the intricate folding of neural tissue. This early process transpires the same way in all brains, whether zebrafish or human, says Sive. So study of mutant zebra fish brains and the genes that play a role in abnormal development shed light on brain malfunction in humans, including autism and mental retardation.

Lecture Details

Location: McGovern Auditorium

“Why study development? It’s fascinating, to think I was once a single cell. There’s a sense of personal interest, and also a fundamental biological interest. It’s universal across biological kingdoms. ”

Hazel Sive

About the Speaker

Hazel Sive

Member, Whitehead Institute
Professor of Biology, MIT

Hazel Sive arrived at Whitehead in 1991. In 1992, she was named a Searle Scholar and received a National Science Foundation Young Investigator Award. Sive earned her undergraduate degree from the University of Witwatersrand in Johannesburg, South Africa, in chemistry and zoology and her Ph.D. from Rockefeller University in molecular biology, in 1986.

Sive traces the earliest stages of neural development in vertebrates. She has identified more than 50 genes involved in the decision to begin making neural tissue from the undifferentiated cells in a young embryo. The work could provide new insights into neurological diseases, spinal cord injuries, and cancer.