Categorized | Science

Lab Letters Issue #10: BIL Gates, Darwin’s Letters, and an Otherworldly Green Rock

Welcome to Lab Letters, FF’s weekly science micro-post! So what’s new? Nothing, just setting up a computer in my own damn cells!



A computer in my body? What could possibly go wrong? (source:


BIL gates can be used to make biological computers

Not the Microsoft founder, mind you. BIL gates stand for Boolean integrase logic gates, which is what a team of Stanford University bioengineers have designed, in conjunction with a transistor-like genetic device. What a mouthful. Let’s break it down.

Stanford University bioengineers have announced that they have created a transistor made of genetic material. Much like how transistors in your computer control electronic signals, these ‘transcriptors’ can amplify or control genetic ones. RNA polymerase is an enzyme responsible for gene expression. Transcriptors control RNA polymerase using integrase, another enzyme that controls RNA polymerase movement. What the Stanford team did was to put this into a device that accepts input signals that directly affect the integrases. Then they designed logic gates  into the system, so that they can directly manipulate the output. They have demonstrated this in E. coli,  one of geneticists’ trusty lab organisms.


A model for a system with a biological transcriptor (grey box). The signals affect the integrases (A and B), which are in a Boolean logic set-up (AND, OR, NAND, etc.) so that the output (RNA pol) can be modified. In this case, the signals could be anything – exposure to a drug, cancer cell markers, changes in insulin levels, etc. The modification can be a change in gene expression, resulting in different marching orders for different cells (make more insulin! tumors, go kill yourselves! let’s make more blood cells!). (source:

Forethought bonus #1: these enzymes work in a variety of organisms from bacteria, fungi, plants, to animals, to minimize compatibility issues.

Forethought bonus #2: the Stanford team released their transistor designs and BIL gates free for public use, to encourage more work and collaboration from anyone interested. Now that’s just nice.

With this introduction of logic functions integrated into biological systems, all that’s left in order to make a biological computer are mechanisms to transmit data and to store data. Wait, they’ve already done that? Awesome.

Excel-lent. (source:



BFFs Charles Darwin (left) and Joseph Hooker (right). (source:


Darwin’s Letters

Cambridge University’s Darwin Correspondence Project has recently released images of Charles Darwin’s previously unpublished personal correspondences with his close friend Joseph Hooker. Darwin, famous for his theory of evolution by natural selection, kept a collection of plants and sought the help of his botanist friend in classifying them. In one particular letter he discusses subtle variations in plants, which he surmises may be ignored until they accumulate. Darwin also confided in his friend about his early ideas about evolution – that species can change. He writes:

 At last gleams of light have come, & I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable. … I think I have found out (here’s presumption!) the simple way by which species become exquisitely adapted to various ends.

The two men also talked about their private lives and families; Hooker wrote to Darwin an hour after his 6 year old daughter died. Darwin suffered a similar event years earlier when his 10 year old daughter, Annie, died as well.

The Darwin Correspondence Project has over 7500 of Darwin’s letters, all neatly scanned, transcribed, and footnoted.


And finally, check out this green rock.

credit: Stefan Ralew/

It may look like your average moss-addled piece of everyday earth chunk, but it actually came from Mercury. Yeah, the planet. Just like conditions on the planet, the rock has a very low iron content and a lower magnetic intensity. Data about Mercury came from NASA’s currently-in-orbit MESSENGER spacecraft.


Now wasn’t that fun? I will see you next week for another dose of fun and FF LL!



DISCLAIMER: The opinions in this post do not necessarily represent the position of the Filipino Freethinkers.