Clamp connection

A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each cell, or segment of hypha separated by septa (cross walls), receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types. It is used to create genetic variation within the hypha much like the mechanisms found in crozier during sexual reproduction.

Figure 1: Cantharellus clamp connection

Figure 1: Cantharellus clamp connection

Figure 3: Clamp connection formation

Figure 3: Clamp connection formation

Formation

Clamp connections are formed by the terminal hypha during elongation. Before the clamp connection is formed this terminal segment contains two nuclei (depicted as green and orange circles in Figure 3). Once the terminal segment is long enough it begins to form the clamp connection. At the same time, each nucleus undergoes mitotic division to produce two daughter nuclei. As the clamp continues to develop it uptakes one of the daughter (green circle) nuclei and separates it from its sister nucleus. While this is occurring the remaining nuclei (orange circles) begin to migrate from one another to opposite ends of the cell. Once all these steps have occurred a septum forms, separating each set of nuclei.