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Twenty — minutes — maybe — more.Naomichoose four wordsmore quotes

epigenetics: fun


Martin Krzywinski / Canada's Michael Smith Genome Sciences Centre / mkweb.bcgsc.ca

2020 `\pi` day art and the piku


visualization + design

Creating the Genome Research November 2012 Cover

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Cover image accompanying Spark: A navigational paradigm for genomic data exploration. Genome Research 22 (11). (zoom, Genome Research)

The Genome Research cover design takes a fun and illustrative approach to visualization. It's both art and science — in a 4:1 ratio.

The cover image accompanies the article by Cydney Nielsen from our visualization group, describing her Spark tool for visualization epigenetics data.

Nielsen CB, Younesy H, O'Geen H, Xu X, Jackson AR, et al. (2012) Spark: A navigational paradigm for genomic data exploration. Genome Res 22: 2262-2269.

Instead of a literal depiction of output from Spark, the final design presents what appears to be necklaces of the kind of tiles that Spark uses for its visual presentation. I took a chance that Genome Research had a sense of humor. Luckily, they did and accepted the design for the cover.

Colored tiles are playfully suspended on vertical strings to illustrate how Spark, presented in this issue, uses clustering to group genomic regions (tiles) with similar data patterns (colored heatmaps) and facilitates genome-wide data exploration.Genome Research 22 (11)

The image was published on the November 2012 issue of cover of Genome Research.

Tools

Illustrator CS5, and a cup (or two) of Galileo coffee from a Rancilio Epoca.

Other Covers

I had two other covers published this year: the PNAS cover accompanied our manuscript about mouse vasculature development and the Trends in Genetics cover was commissioned.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Cover image accompanying our article on mouse vasculature development. Biology turns astrophysical. PNAS 1 May 2012; 109 (18) (zoom, how it was made, PNAS)
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Cover image for the human genetics special issue. Trends in Genetics October 2012, 28 (10) (lowres, hires, how it was made, Trends in Genetics)

source of design

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
To lower this computational barrier, particularly in the early data exploration phases, Spark was developed as an interactive pattern discovery and visualization tool for epigenomic data. (Spark)

Thinking about design ideas for the cover, I looked to the kind of visual motifs that Spark used for inspiration. Immediately the colorful tiles, which represent clustered data tracks, stood out.

Spark's output is very stylized, colorful and high contrast. It was important to preserve this aesthetic in the design. I also wanted to incorporate the idea of clustering in the design, as well as the concept that the clusters represented data from different parts of the genome.

While it was not important to illustrate how Spark organizes and analyzed data explicitly — in fact, I wanted these aspects to be subtle — it was important that the cover illustration had connections to Spark at several levels.

Spark

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Many genomics techniques produce measurements that have both a value and a position on a reference genome, for example ChIP-sequencing.

Spark was created by Cydney Nielsen, who works with me at the Genome Sciences Center. It is designed to mitigate the difficulties arising from the fact that genome-wide data is typically scattered across thousands of points of interest.

Genome browsers integrate diverse data sets by plotting them as vertically stacked tracks across a common genomic x-axis. Genome browsers are designed for viewing local regions of interest (e.g. an individual gene) and are frequently used during the initial data inspection and exploration phases.

Most genome browsers support zooming along the genome coordinate. This type of overview is not always useful because it produces a summary across a continuous genomic range (e.g. chromosome 1) and not across the subset of regions that are of interest (e.g. genes on chromosome 1). Spark addresses this shortcoming and provides a way to help answer questions like: What are the common data patterns across genes start sites in my data set?

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Spark's approach to analysis and display of epigenetic data.

Spark's visualization is driven by clustering data tracks (e.g. ChIP-seq coverage) from across equivalent regions (e.g. gene start sites). The clustered tracks are displayed as heatmaps, with each row being a data track and each column a windowed region of the genome.

early comps

With fond memories of Monte Carlo simulations from my physics days, I set out to simulate some realistic-looking, but entirely synthetic, Spark cluster tiles.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
A collection of synthetic Spark tiles, each 7x20.

My first idea was a design which would show these tiles falling, perhaps accumulating on a pile on the ground. Quick prototypes of this idea were disappointing. The tiles appeared flimsy and too complex, while the image was largely empty. I spent several hours messing around with the rotation and pseudo-3D layout, but could not find anything that was satisfying.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Spark tiles, falling.
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Early attempt at a design. Meh.

I thought to do this right would require a proper simulation within a 3D system.

refining the design

To address the fact that the tiles felt flimsy and overly complicated and the design lacked depth, I simplified the tile simulation to generate 5x5 tiles. These simpler representations still embodied how Spark displayed data, but did so minimally.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
A second attempt at simulating Spark clusters.

To keep with the idea that the clusters come from different regions of the genome, I thought of arranging them along line segments. Unlike the design in which the tiles were falling, this constrained the layout significantly and allowed me to play with the design to make it look like the clusters were draped over it. By casting a light shadow behind each string of tiles, a subtle 3D effect could be achieved while still keeping the design within a plane.

There are 11 orientations of tiles created by rotating a thin square around the vertical axis with a slight forward tilt. There are 5 rotations to the left and right at angles 10, 26, 46, 66 and 80 degrees. The rotation was achieved using Illustrator's Extrude and Bevel 3D filter.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Layout of tiles.
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Rotated tiles with Spark clusters.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Flight and Fall by Rachel Nottingham. (artist's site)

The layout and rotation of the tiles was inspired by Flight and Fall by Rachel Nottingham, a mobile of paper birds.

I wanted to keep the layout of the spark tiles pleasant, without being too organized. I find this to be a difficult balance to achieve — natural randomness is deceptively difficult to create by hand.

final image

Four different versions of the design were submitted to Genome Research. I was happiest with the treatment in which the tiles maintained their color and the Spark clusters were projected as tones of white. This designed felt more solid and punchy — I feel like you can reach out and touch one of those strings.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Final Spark cover designs. The top left one was chosen by Genome Research.

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news + thoughts

The Outbreak Poems

Sat 04-04-2020

I'm writing poetry daily to put my feelings into words more often during the COVID-19 outbreak.

Patience but
know
where to put it.
Favourite 
looks
words tastes phrases
ex
foreign origins.
Melody
same
feelings different.
Desire
life
remote control.
Sun rays burn
off
night dust into
day.
Sanitize
in
perfection now.
Door closes
next
next door closes
next
nothing is left open.
One of the
pair
is from the other.
Eyes look at
eyes
and see themselves.
Look back and
pass
destinations.

Read the poems and learn what a piku is.

Deadly Genomes: Genome Structure and Size of Harmful Bacteria and Viruses

Tue 17-03-2020

A poster full of epidemiological worry and statistics. Now updated with the genome of SARS-CoV-2 and COVID-19 case statistics as of 3 March 2020.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Deadly Genomes: Genome Structure and Size of Harmful Bacteria and Viruses (zoom)

Bacterial and viral genomes of various diseases are drawn as paths with color encoding local GC content and curvature encoding local repeat content. Position of the genome encodes prevalence and mortality rate.

The deadly genomes collection has been updated with a posters of the genomes of SARS-CoV-2, the novel coronavirus that causes COVID-19.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Genomes of 56 SARS-CoV-2 coronaviruses that causes COVID-19.
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Ball of 56 SARS-CoV-2 coronaviruses that causes COVID-19.
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
The first SARS-CoV-2 genome (MT019529) to be sequenced appears first on the poster.

Using Circos in Galaxy Australia Workshop

Wed 04-03-2020

A workshop in using the Circos Galaxy wrapper by Hiltemann and Rasche. Event organized by Australian Biocommons.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Using Circos in Galaxy Australia workshop. (zoom)

Download workshop slides.

Galaxy wrapper training materials, Saskia Hiltemann, Helena Rasche, 2020 Visualisation with Circos (Galaxy Training Materials).

Essence of Data Visualization in Bioinformatics Webinar

Thu 20-02-2020

My webinar on fundamental concepts in data visualization and visual communication of scientific data and concepts. Event organized by Australian Biocommons.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Essence of Data Visualization in Bioinformatics webinar. (zoom)

Download webinar slides.

Markov models — training and evaluation of hidden Markov models

Thu 20-02-2020

With one eye you are looking at the outside world, while with the other you are looking within yourself.
—Amedeo Modigliani

Following up with our Markov Chain column and Hidden Markov model column, this month we look at how Markov models are trained using the example of biased coin.

We introduce the concepts of forward and backward probabilities and explicitly show how they are calculated in the training process using the Baum-Welch algorithm. We also discuss the value of ensemble models and the use of pseudocounts for cases where rare observations are expected but not necessarily seen.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Markov models — training and evaluation of hidden Markov models. (read)

Grewal, J., Krzywinski, M. & Altman, N. (2019) Points of significance: Markov models — training and evaluation of hidden Markov models. Nature Methods 17:121–122.

Background reading

Altman, N. & Krzywinski, M. (2019) Points of significance: Hidden Markov models. Nature Methods 16:795–796.

Altman, N. & Krzywinski, M. (2019) Points of significance: Markov Chains. Nature Methods 16:663–664.