Ryoma Ohi, Ph.D., Associate Professor Department of Cell and Developmental Biology, University of Michigan Medical School

Parthenogenesis means reproduction from an egg without fertilization. It occurs naturally in some plants, insects, and fish, but is not normally seen in mammals. However, it is possible to “activate” a mammalian egg so that it undergoes the early stages of embryonic development without fertilization by sperm. Such parthenogenic embryos die well before birth, but they provide important model systems for studying some aspects of development that are not possible to study in normal embryos derived from fertilized eggs. This is an image of a BPE-1 cell, which was derived from a cow embryo that had initiated development parthenogenetically. BPE-1 cells are flat, making them ideal specimens for the study of cell structure by optical microscopy. Shown here is the web-like distribution of actin filaments (yellow) and mitochondria (pink), the energy-producing organelles of the cell.

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