A genome analysis of endoreplication in the Drosophila ovary.
Gene amplification is used by follicle cells to increase the copy number of Drosophila chorion genes, which encode structural components of the eggshell. A new study by Claycomb et al. in this issue of Developmental Cell raises the possibility that gene amplification might also be used for the developmental patterning of the egg chamber and oocyte.
Summary Clonal propagation or apomixis is common in the plant kingdom. Among trees, agamospermy and vegetative propagation are relatively rare in nature. In this paper the roles of different modes of propagation in the survival strategy of three different plant groups are discussed. Conclusions for tree breeding strategies are drawn: clones have an important role to play. Greatest genetic gain and flexibility are attained when both sexual and clonal propagation occur. Genetic diversity should be maintained in any strategy.