Competition between cells to join the germline?

Sexually-reproducing animals produce germ cells, totipotent cells able to give rise to entire organisms. A key question in germ cell research is how this totipotency is regulated.  In many animals, including mammals, germ cells are specified late in embryogenesis by cell-cell interactions, but the signals that specify germ cell fate in such cases are not understood.  We have developed the tardigrade Hypsibius dujardini (pictured at right) as a model system for comparative studies in germline development. Previous work in our lab has suggested that cells in an equivalence group may be germ cell precursors. These cells have the same potential cell fates, but only one cell is chosen stochastically to internalize and become a candidate germ cell, while the other divides at the embryo surface and adopts an alternate fate. These observations suggest that cells may compete to enter the germline. I am identifying and characterizing germ cells in H. dujardini, and I am working on developing methods to disrupt gene function by RNA interference to further address this issue.  These studies may provide insight into how cells can compete to enter the germline, and may provide a system for long-term study of the evolutionary consequences of such competition.

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