Genome

Take a  tour of your genome.

Flyover:
An overview of the landscape of one of your chromosomes.

Chromosome close up:
Zoom in on a chromosome to explore its structure and some of the locations along its length.

Genome FISHing:
Highlight key chromosome features, and browse a public database for further detail.

Genome spots:
Access animations and video clips that tell stories about your genes.

Background

The social amoebae (Dictyostelia) are a diverse group of Amoebozoa that achieve multicellularity by aggregation and undergo morphogenesis into fruiting bodies with terminally differentiated spores and stalk cells. There are four groups of dictyostelids, with the most derived being a group that contains the model species Dictyostelium discoideum.

Results

We have produced a draft genome sequence of another group Dictyostelid, Dictyostelium purpureum, and compare it to the D. discoideum genome. The assembly (8.41x coverage) comprises 799 scaffolds totaling 33.0 Mb, comparable to the D. discoideum genome size. Sequence comparisons suggest that these two Dictyostelids shared a common ancestor approximately 400 million years ago. In spite of this divergence, most orthologs reside in small clusters of conserved synteny. Comparative analyses revealed a core set of orthologous genes that illuminate Dictyostelid physiology, as well as differences in gene family content. Interesting patterns of gene conservation and divergence are also evident suggesting function differences; some protein families, such as the histidine kinases, have undergone little functional change, whereas others, such as the polyketide synthases, have undergone extensive diversification. The abundant amino acid homopolymers encoded in both genomes are generally not found in homologous positions within proteins, so they are unlikely to derive from ancestral DNA triplet repeats. Genes involved in the social stage evolved more rapidly than others, consistent with either relaxed selection or accelerated evolution due to social conflict.

Conclusions

The findings from this new genome sequence and comparative analysis shed light on the biology and evolution of the Dictyostelia.