Conserved developmental transcriptomes in evolutionarily divergent species

Here we show that the anatomical similarities are accompanied by extensive transcriptome conservation. Using RNA sequencing we compared the abundance and developmental regulation of all the transcripts in the two species. In both species, most genes are developmentally regulated and the greatest expression changes occur during the transition from unicellularity to multicellularity. The developmental regulation of transcription is highly conserved between orthologs in the two species. In addition to timing of expression, the level of mRNA production is also conserved between orthologs and is consistent with the intuitive notion that transcript abundance correlates with the amount of protein required. Furthermore, the conservation of transcriptomes extends to cell-type specific expression.These findings suggest that developmental programs are remarkably conserved at the transcriptome level, considering the great evolutionary distance between the genomes. Moreover, this transcriptional conservation may be responsible for the similar developmental anatomies of Dictyostelium discoideum and Dictyostelium purpureum.Comparisons between morphology, physiology and developmental transitions of organisms have been used for some time to study evolutionary relationships between species. We can now use genome sequence comparisons and start to relate genetic information to organismal function and morphology. High-throughput methods for the analysis of RNA, protein and metabolites are beginning to bridge the gap between genomes and functions, and evolutionary comparisons between organisms using these methods are increasing our understanding of the relationship between genes and function.Gene regulation is sometimes surprisingly similar between divergent species, revealing common pathways in fundamental processes despite vast evolutionary distances [1,2]. Comparing the transcriptomes of evolutionarily distant organisms has revealed ancient conserved genetic networks and helped in ass