442: Developmental biology: Reproduction in clusters
Homeobox genes have some quirky features: they huddle together and tend to be expressed in the order that they appear in their cluster. A new cluster, specific to reproductive development, has now been discovered.
The survival of animal species depends upon the proper development of germ cells: oocytes and sperm. In mammals, this process is tightly coordinated with the development of non-reproductive cells nearby, such as Sertoli cells, which nourish developing sperm cells1. Changes in the delicate interactions between reproductive and non-reproductive cells are often a source of decreased fertility, so the appropriate regulation in time and space of the underlying genetic determinants must be essential. Writing in Cell, MacLean et al.2 describe how they identified a new set of these genetic determinants — a cluster of homeobox genes that are expressed during the development of germ cells. The clustering of these genes may help to determine their spatial and temporal regulation.
Hox genes are conserved through much of Animalia, and help explain the development of novel structures within existing body forms. Very neat.