A twin spot generator allows lineage analysis of adjacent embryonic cells

 A collaboration between the labs of Norbert Perrimon and Ting Wu has allowed development of a Drosophila system for the differential analysis of each of the two daughter cells resulting from a mitotic division.  The system relies on recombinase based rejoining of two chimeric alleles for EGFP and mRFP.  The induced recombination results in stable expression of EGFP in one daughter cell, and of mRFP in the other allowing researchers to independently trace their descendants .  By combining this technology with genetic disruptions downstream of the fluorescent markers, researchers will be able to use this tool to assay the effect of the disruption on a single cell, and its progeny, relative to its developing, wild-type, neighbor. 
Their results were published in the August 2009 issue of Nature Methods.