For an example, see E. Coli K-12 MG1655 operon thrLABC.
Multiple different transcription units can be produced by a single operon, see: operon vs transcription unit.
It is hard for complex organisms to evolve because longer DNA means longer replication time by 
Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16Because DNA replication is a key limiting factor of bacterial replication time, such organisms are therefore strongly incentivized to have very minimal DNAs.
Power, Sex, Suicide by Nick Lane (2006) 7 "Why bacteria are simple" page 169 puts this nicely:
Bacteria replicate at colossal speed. [...] In two days, the mass of exponentially doubling E. coli would be 2664 times larger than the mass of the Earth.Luckily this does not happen, and the reason is that bacteria are normally half starved. They swiftly consume all available food, whereupon their growth is limited once again by the lack of nutrients. Most bacteria spend most of their lives in stasis, waiting for a meal. Nonetheless, the speed at which bacteria do mobilize themselves to replicate upon feeding illustrates the overwhelming strength of the selection pressures at work.
Ways in which it can happen:
Graph of life
. Source. horizontal gene transfer transforms the tree of life into the graph of life! Fuck my life.Current Wikipedia seems to say that this refers specifically to cells taking up DNA from other dead cells as in the Avery-MacLeod-McCarty experiment, excluding other types of horizontal gene transfer like bacterial conjugation
Structure of Hen Egg-White Lysozyme: A Three-dimensional Fourier Synthesis at 2 Å Resolution (1965) by Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16www.nature.com/articles/206757a0 on Nature 181, 662-666. Paywalled as of 2022. Has some nice pictures in it.
Flow Cytometry Animation by StarCellBio (2015)
Source. Technique widely used to measure the size of DNA strands, most often PCR output of a region of interest.
A simple sample application is gel electrophoresis alelle determination.
Wikipedia defines Mind uploading as a synonym for whole brain emulation. This sounds really weird, as "mind uploading" suggests much more simply brain dumping, or perhaps reuploading a brain dump to a brain.
Superintelligence by Nick Bostrom (2014) section "Whole brain emulation" provides a reasonable setup: post mortem, take a brain, freeze it, then cut it into fine slices with a Microtome, and then inspect slices with an electron microscope after some kind of staining to determine all the synapses.
Likely implies AGI.
Ciro Santilli invented this term, derived from "hardware in the loop" to refer to simulations in which both the brain and the body and physical world of organism models are modelled.
E.g. just imagine running:
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.
Figure 3. Visual Studio Code extension installation.
Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact