You have reached, Marco van Zwetselaar’s professional domain. I’m also at, my family’s long time personal digital namespace. The web site of my company Zwets IT is

Who is

My professional career started in academic research deep in the past millennium. Then there was a twenty year stint in commercial IT (details). I then moved back into research, and have since been immersed in genomics and bioinformatics.

After ten years building from scratch KCRI’s bioinformatics unit, I moved on in March 2023 to continue as an independent contractor with my own company, Zwets IT. Read my CV here.


I tremendously enjoyed setting up the bioinformatics unit at KCRI in Moshi, Tanzania. This meant single-handedly building an affordable but adequate high-performance cluster (, developing pipelines such as the KCRI CGE Bacterial Analysis Pipeline (BAP), teaching basic and advanced bioinformatics courses, and performing countless analyses for projects around Africa – including Tanzania’s first and only published SARS-CoV-2 genomes.

I hope to continue in this line of work, building local bioinformatics capacity at other sites in Africa. I’m open to other gigs.


Bioinformatics is my work, programming is my craft and passion. I must have typed my first line of BASIC ca. 1979 on a Philips P2000. Then came Pascal, LISP and C++ in the 80s – as well as an obscure DBase3 language which is lost in the haze.

I then rode the third AI wave of the early 90s, picking up Prolog and Scheme, and a heap of mathematical statistics in the wake of the newborn field “Neural Networks”. Theoretical CS introduced me to the austere beauty of the lambda calculus and combinatory logic, and cemented my love for functional languages.

Haskell still is my favourite programming language, by a large margin. My wish is that R dies and reincarnates in Haskell. Recommended recreational programming language excursions: Erlang, Newspeak, Pure, and don’t miss Parallel Brainfuck.

Ah, work

When play time university was over, after building one of the earliest .nl web sites – running off my personal SGI Indigo at RIVM, and featuring my homebrew “ZWebcam” – I spent the 90s and 00s professionally cranking out uncountable lines of C, C++ and Java.

Over the years my work shifted to consulting and architecture (see my CV), but even as an Enterprise Architect I refused to give up coding. My motto at Atos Origin: “As long as I don’t become a PowerPoint architect”.

In 2012 I moved from consulting back to research, and, as a bioinfomatician, very much back to hands-on work. My current day-to-day languages are Bash/GNU, Python, C/C++ and (reluctantly) R. I’m open to programming assignments, provided they aren’t front-end and can be done on Linux with open source tools.

Footnote: why

I started this site when GitHub enabled personal domains for pages. I already owned, the io stuck, and so it became Apart from the geeky pun, ask any Italian why I/O makes sense.