标签：#futurism

A salamander can lose a leg and grow a new one. Cut a zebrafish's fin and it simply builds another. Mammals, us included, got the consolation prize: a scar. For a century, biologists assumed that somewhere on the evolutionary road to becoming warm-blooded, fast-moving animals, we traded regeneration away for good. Two research teams working on opposite sides of the planet have just made that assumption look wrong. The headline is almost hard to believe: the ability to regrow lost body parts may not have been deleted from our biology at all. It may simply have been switched off, and switches can be flipped back on. The genetic "remote control" that stopped working The first clue comes from a team at the National Institute of Biological Sciences in Beijing, working with genomics powerhouse BGI-Research. Publishing in Science , they zeroed in on a gene called ALDH1A2 , the instruction sheet for an enzyme that turns vitamin A into retinoic acid, a molecule that acts like a foreman on a construction site, telling cells where to go and what to build during tissue repair. Animals that regenerate freely crank this gene up at the wound site. Mice, it turns out, still carry the same gene. They've just lost the genetic "remote controls," the regulatory DNA that tells the gene to fire after an injury. The hardware is intact; the software command was disconnected somewhere in evolution. So the researchers reconnected it. By reactivating that dormant switch and restoring the flow of retinoic acid, they got mice to regenerate damaged outer-ear tissue, something a normal mouse simply cannot do. In their own words, they had found "a genetic switch involved in the evolution of regeneration." Meanwhile, in Texas, they regrew a limb joint The second piece of evidence lands the point with force. At Texas A&M, a group led by Dr. Ken Muneoka took a different route to the same destination. Instead of editing a genetic switch, they used a precisely timed sequence of two signaling proteins.

I started as a Java developer, but for some time now, I have broadened my horizons. Recently, I thought about how early languages were dedicated to a single target and platform, and now they are broadening their focus. In this post, I want to write down my thoughts in the hope that it may be useful to others, probably to my future self. Definitions You may have been wondering about the title terms. I'm pretty sure that if you read this post, you have a pretty good picture of what a programming language is. Some may disagree on some finer points or raise a hair-splitting one, but it's not a PhD thesis, only a post on my blog. I must define what I mean by target and platform in the context of this post before going further. Target A target only makes sense in the context of compiled programming languages. For example, C's target is native code , and Java's is bytecode . Platform A platform is the system that will ultimately run the target. Native code runs on the operating system; bytecode on the JVM. Early programming languages Early programming languages had a single target and platform. I mentioned C and Java, but Ruby, Python, JavaScript, etc., were all the same. Programming language Target Platform C Native code Operating system C++ Native code Operating system Java Bytecode JVM Python - Python runtime TypeScript JavaScript Browser & server-side JS JavaScript - Browser I believe it was the case for a long time. It changed at some point, though. Multi-target is the new black The first time I heard about multi-target was in Scala. Scala came from the era of single-target and targeted bytecode on the JVM platform. However, in 2015, Martin Odersky announced Scala.js, which added JavaScript to Scala's target. The original article was published on InfoWorld, but it seems to have redirection issues nowadays. Here's the introduction on a copy: Scala, developed as a functional and object-oriented language for the JVM, is now multiplatform, with developers using it in abun