22nd Dec., ’12. In an article entitled, “Algal genomes reveal evolutionary mosaicism and the fate of nucleomorphs” published in the 6th Dec. ’12 issue of Nature (492:59-65), Bruce A. Curtis and his 72 associates (affiliated to different universities of Canada, the USA, the UK, Czeck, Germany, France, Sweden, Australia and New Zealand ) have described how the genes that encode the various proteins that function in these organelles were transferred to the nucleus during the course of evolution by a process called Endosymbiotic Gene Transfer (EGT). The above authors have sequenced the nuclear genomes of two unicellular algae that are remarkable in their genetic and cellular complexity: the cryptophyte Guillardia theta and the chlorarachniophyte Bigelowiella natans. It may be mentioned here that in both G. theta and B. natans plastids are bound by four membranes. In cryptophytes, the outermost plastid membrane is continuous with the nuclear envelope and a cluster of ribosomes are embedded in it. According to these authors they co-translationally insert nucleus-encoded, organelle-targeted proteins. Another interesting feaute of these unicellular algae is that they show between the inner and outer membrane pairs i.e. periplastidial compartment (PPC) containing the nucleomorph (NM). The latter is the relict nucleus of the eukaryotic endosymbiont. The approximate numbers of protein-coding genes in the plastid, mitochondrial (MT), nucleomorph and nuclear genomes of G. theta and B. natans have been determined. Click the figure to view them in higher magnification.