No CrossRef data available.
Published online by Cambridge University Press: 16 July 2018
The problem of how the sperm activates the egg has captivated the attention of cell and developmental biologists since the turn of the century. An early focus concerned species-specific fertilisation and the pioneering work of Lilly and Tyler (Tyler & Tyler, 1966) used immunological analogies to provide explanations of species-specific fertilisation. Contemporary work has focused on the identity of unique receptors on the sperm and the egg as exemplified in the work of Lennarz (Ohlendieck & Lennarz, 1996), Vacquier (Vacquier, et al., 1995) and Wasserman (1999). Lately, this approach has provided unexpected insights on how speciation might occur. Speciation requires reproductive isolation and creative research from the Vacquier laboratory has demonstrated how reproductive barriers might occur through rapid evolution of sperm/egg recognition systems (Lee et al., 1995).
Studies on the cell biology of activation received a major impetus in the 1930s with Mazia's observation of a calcium increase in eggs of the sea urchin following fertilisation (Mazia, 1937). His discovery, however, was a premature one in that there was no satisfactory model at that time for explaining how a calcium increase could affect cell activity. It took almost 40 years to develop a paradigm, and this came from studies on muscle and nerve which revealed how calcium increases could somehow control cell activity. Work in the 1970s rapidly established a similar role for calcium in activation of the egg at fertilisation. The first break-through was the direct demonstration by Steinhardt & Epel (1974) that calcium was involved in egg activation, through manipulation of calcium levels in sea urchin oocytes by use of calcium ionophores.