Type II enzymes and no part shipment in iGEM 2019

In April, iGEM announced two major changes in this year’s competition: teams will no longer need to physically submit their parts; and parts can be compatible with assembly standards based on Type II restriction enzymes.

Moving on from BioBricks

In the distant 1990s, cloning and genetic assembly was a complicated thing. A genetic engineer had to be creative in the choice of restriction enzymes and the order of adding parts together. What is more, obtaining DNA parts required a gel purification step, making the building of a construct a tenuous and complicated process. 3A Assembly was the first standardized genetic construction method of joining two DNA parts. Through exchanging restriction enzyme recognition sites (restriction sites) and antibiotic selection markers, one could add iteratively parts to an sequence without the need to digest and purify the origin vectors as a separate step. This practice was widely adopted by the early synthetic biologists and led to various assembly standards. BioBricks (and in particular BioBrick RFC[10]) were adopted by the iGEM competition. All teams had to submit their genetic parts according to this standard so that one could combine and reuse parts in future designs.

Albeit successful, the BioBricks standard is nowadays obsolete. The introduction of isothermal assembly methods, such as Gibson Assembly, allowed the simultaneous assembly of multiple parts. Furthermore, the development of of methods based on Type IIS restriction enzymes, such as MoClo and Loop assembly, allow the easy construction of complex genetic constructs, are easy to multiplex, and are compatible with automated genetic construction used in biofoundries. iGEM had the submission of BioBrick compatible parts as a competition requirement. Therefore, many iGEM teams that were using other cloning techniques in their projects had to undertake an extra genetic assembly set of experiments, making their parts compatible with BioBricks.

This year iGEM announced that the parts can be accepted in two formats: compatible with the BioBricks or Type IIS standard. iGEM incorporated the feedback from the community and showed that a competition around innovation should not ignore technological breakthroughs. And the reaction from the community  is so far enthusiastic…

Synthesis replaces shipment

iGEM competition revolves around collaboration and sharing. The teams therefore need to send their parts, which are then available to future teams to use in new designs or improve. This in principle great idea had a few problems though. The construction of parts assembled in the designated vector was creating more experimental workload to the teams. In addition, shipping the samples to the US from abroad could be tricky, often resulting to administrative workload and samples stuck in customs. Last but not least, the receipt of all these samples from different labs meant that iGEM had to do a lot of quality control work.

This year, iGEM announced that teams need to send samples no more. In partnership with IDT and Twist Bioscience, iGEM will be synthesizing the part electronically submitted by the teams. As mentioned in the announcement:

In iGEM’s vision… synthetic biologists no longer manipulate DNA; …you would synthesize your designs entirely.

I am pretty sure this year’s team will appreciate these changes and the extra time available to spend in designing, building, and testing their DNA parts!

Do you want to share your iGEM project with the community? Contact PLOS synbio on Twitter or our editor Kostas Vavitsas by email to arrange a blog post about the problem you aim to solve!