
Circle of Cancer
This Circos depiction of a tumor genome provides the cover of 30 November 2011 Science's Transitional Medicine issue in which Roychowdhury et al. describe personalized treatment for patients with colorectal and prostate cancer. By quickly sequencing normal and tumor DNA and RNA, suitable therapies can be tailored for the specific mutations identified.
1 2011 Personalized Oncology Through Integrative High-Throughput Sequencing: A Pilot Study Science Translational Medicine 3:111ra121.

Towards a Human Pan-Genome
As reported in Wired, Li et al. use Circos to visualize the comparison of structural variation in two sequenced human genomes: Asian and Yoruban (African). It's been over 10 years since the first reference genome (comprising DNA from multiple individuals) was reported. Technological advancements have made it possible to now sequence 1000's of human genomes to identify genetic variations for tracing evolution, determining population patterns, and assessing disease susceptibility and other phenotypic traits.
2011 Structural variation in two human genomes mapped at single-nucleotide resolution by whole genome de novo assembly Nature biotechnology 29:723-730.
2010 Building the sequence map of the human pan-genome Nature biotechnology 28:57-63.

Hemolytic–Uremic Syndrome Outbreak
Rasko et al. use Circos to show how the E. coli strain implicated in the German outbreak of hemolytic-uremic syndrome varies from other strains in their New England Journal of Medicine paper, where they find that "the genome of the German outbreak strain can be distinguished from those of other O104:H4 strains because it contains a prophage encoding Shiga toxin 2 and a distinct set of additional virulence and antibiotic-resistance factors."
NEJM created an animation that explains the visualizations. The paper was blogged by Pacific Biosciences.
2011 Origins of the E. coli Strain Causing an Outbreak of Hemolytic-Uremic Syndrome in Germany The New England journal of medicine published ahead of print:-.

Circos Maps Cancer Landscapes
Nature features an article by Heidi Ledford, The Cancer Genome Challenge, which discusses the progress and challenges of identifying structural variation signatures in cancer genomes.
Circos images are used throughout the piece, taken from the COSMIC project (Catalogue of Somatic Mutations in Cancer).
2010 Big science: The cancer genome challenge Nature 464 (7291) 972-974.

Circos Maps Cancer Landscapes
Nature features an article by Heidi Ledford, The Cancer Genome Challenge, which discusses the progress and challenges of identifying structural variation signatures in cancer genomes.
Circos images are used throughout the piece, taken from the COSMIC project (Catalogue of Somatic Mutations in Cancer).
2010 Big science: The cancer genome challenge Nature 464 (7291) 972-974.

Massive Genomic Rearrangement Acquired in a Single Catastrophic Event during Cancer Development
Stephens et al. report on a phenomenon by which a cell accumulates a large number of rearrangements in a single catastrophic event. This phenomenon, which they call chromothripsis, can be seen in at least 2%–3% of all cancers and in about 25% of bone cancers.

Successive Duplications in Paramecium
A visual representation of ancestry analysis of 85 dog breeds and Eurasian gray wolves.
17 2010 Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication Nature 464 (7290) 898-902.

Successive Duplications in Paramecium
This unusual, but effective, Circos image shows successive duplications in the Paramecium genome.
The exterior circle displays all chromosome-sized scaffolds, and the three interior circles show the reconstructed sequences obtained by fusion of the paired sequences from each previous step.
57 2006 Global trends of whole-genome duplications revealed by the ciliate Paramecium tetraurelia Nature 444 (7116) 171-178.

Circos Appears on the Cover of Nature Biotechnology
An illustration of genome annotations of the E coli genome appears on the cover of Nature Biotechnology (vol 27, no 11). The image accompanies the article The transcription unit architecture of the Escherichia coli genome by Cho et al.
23 2009 The transcription unit architecture of the Escherichia coli genome Nature biotechnology 27 (11) 1043-1049.

Circos Illustrates Genome Structure of Maize
The Maize sequence paper uses Circos to show genome structure and annotations. Links inside the circle show homologous sites of duplicated gene blocks.
Circos Sniffs out Dog Genetics in American Scientist
The completion of the draft version of the dog genome revealed large overlaps between dog and human genomes. Working with American Scientist, Martin Krzywinski generated an illustration showing blocks of similarity between the two genomes.
The illustration accompanies the article Genetics and the Shape of Dogs, by Elaine Ostrander.
Circos has been used and referenced in numerous scientific publications (376 as of Apr 2012, see published images).
Journals with the most papers with Circos images are