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Saturday, June 11, 2016

THE CUTTING EDGE OF GENETIC ENGINEERING

Some of you have recently read about CRISPR and gene drive as genetic techniques to control, if not eliminate, the population of mosquitos.  Note that reproduction must be sexual, so bacteria and viruses do not qualify for this treatment.  Humans would.  Rather than trying to describe the concept, I would recommend you read this The New Yorker article by Michael Specter (left), and to simplify the process, let me draw a quote from Sculpting Evolution, led by Kevin Esvelt:


Gene drive systems are capable of altering the traits of wild populations and associated ecosystems. 


Named for the ability to "drive" themselves and nearby genes through populations of organisms over many generations, these genetic elements can spread even if they reduce the fitness of individual organisms. They do this by ensuring that they will be inherited by most - rather than only half - of offspring. Preferential inheritance can more than offset costs to the organism, permitting rapid spread through the population. CRISPR-based genome editing allows us to build gene drive systems capable of spreading different useful changes, including those that will eventually suppress or eliminate the target population. 

Global drive systems are likely to spread to every population of the target species in the world. 

Local drive systems are confined to local populations. Daisy drive systems are an example of a powerful but local form of drive.

Key Resources 
- A detailed gene drive FAQ focused on CRISPR-based global drive systems
- A comprehensive analysis of safeguards for gene drive research
- All current gene drive research projects and collaborations involving the Sculpting Evolution Group
- An explanatory guide to daisy drive systems, which are CRISPR-based but will alter only local populations.

For the less informed, CRISPR is pronounced crisper, is the acronym for Clustered Regularly Interspaced Short Palindromic Repeats, and was only described less than two decades ago by Yoshizumi Ichino of Osaka University in Escherichia coli, the microorganism I dealt with in my PhD Dissertation (Irradiation of Escherichia coli in the Visible Spectrum with a Tunable Organic-Dye Laser Energy Source, Applied Microbiology).  However, it took until 1993 for Spanish researcher Francisco Monica to identify them as short regularly spaced repeats (SPSR).  In 2002 he renamed the cluster CRISPR.   Then the following year Gene Drive was first outlined by Austin Burt of Imperial College London.  Note the internationalization of genetic engineering, and here, the absence of Americans.  

You've got to wonder if our religious morality has been impeding progress, if you can call it that, for, as would be expected in a Nation having an 80-90% belief in God rate, anti-cloning disapproval is also up in that range.  Probably a poor comparison, but China has initiated a massive cloning factory to feed its people.  Two-thirds of Americans think it is morally wrong to clone animals.  A actually had a HuffPo on Human Cloning.  The UK allows therapeutic human cloning.


All that said, I should underscore that gene drive works because, while nature generally results in 50% of genes being inherited, this latest scientific technique increases this percentage towards 100%. Thus, in a short period, mosquito populations can be decimated, if not eliminated.  A key point, though, is that gene drive could well not harm the wild population count.  GD can only prevent the mosquito from carrying the microorganism that cause zika or malaria!  In any case, mosquitos have been around for more than 200 million years, while our early ancestors possibly began to spin off only 2 million years ago.

So how can any individual or organization be against this benefit to society?  Well, we are a careful community.  Even the National Academies of Sciences, Engineering and Medicine stress time, research and open interaction before doing anything drastic.

Let's say it is also feasible to reverse-engineer gene drive.  That is, if we really screwed up and the consequences were a lot worse than anticipated, scientists say that you can in time correct the error.  If this is true, as almost half a million die yearly from malaria, can a decade of careful discussion be justified?  Incidentally, the mosquito does not get you, it is the parasite it deposits in your blood stream.

The question then always comes up.  Can gene drive be used by your enemy to destroy the people in our country?  Theoretically yes, but the odds of anything seriously happening are infinitesimal, and this has to do with life cycle.  A male mosquito is only "sexually effective" for a few days.  Females actually can remain fertile for a couple of months.  Thus, while a mosquito population can quite quickly be affected, it would take centuries, if not millennia, for Homo sapien communities to be impacted.  In the process, any quick check of your blood would reveal the invasion, so reverse engineering can be utilized to correct your future course.

This leads to my nemesis, cockroaches.  They have been around for 300 million years.  You think gene drive can now, suddenly, eliminate them?  To influence some of my friends, cockroaches, apparently, in addition to everything else, can also cause chocolate allergies.  Anyway, there are up to 10,000 species of cockroaches and many birds, rats and insects depend on them for their diet.  Then, the disappearance of them could mean furry animals, eagles and the like...then....  Worse, for me, cockroaches are essential to the nitrogen cycle.  Has something to do with their poop and I refuse to go there.

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