Glow in the Dark Snake?

*FYI - If you are a grant proposal reviewer then yes, I have a 2009 GC Round 4 proposal submitted for review.

That’s how it began for me – I wanted to make a snake that would glow in the dark. I wanted to insert a gene for luciferase (from the firefly) into a snake. What an awesome pet! It would be great but there was a catch – how do you do in vitro gene insertion into the embryo of a reptile? Mammals are relatively easy since you take the eggs out, modify them, and then put them back in the uterus. Although some reptiles give birth to live young, most reptiles lay eggs and must deposit a shell around the embryo when they ovulate. I suppose live bearing reptiles would be easiest but either way it gets very complicated to put the modified zygote back into the reproductive tract where it can be properly excreted.

But it also occurred to me that birds have a similar problem – the fertilized egg must pass through the magnum and isthmus to be coated with a shell when the egg is ovulated. Certainly the poultry industry would very interested in this strategy - Tyson Foods I'm looking at you! So I started thinking about how I would accomplish this. Might it be possible by doing in vivo laparoscopic follicular aspiration, followed by a quick ex vivo egg surgery, and finished with laparoscopic re-implantation? But these eggs are relatively large - could you even use laparoscopy? Wow! There were a lot of things to consider. But is there an easier way?

There was once a crazy idea about attaching a gene to the head of a sperm and letting the sperm carry the DNA to the egg. It was known as Sperm Mediated Gene Transfer (SMGT). But there were many technical problems including the fact that the gene did not insert into the chromosomes and therefore did not last through multiple replications of the cells. It was just present in the egg for a little while but apparently not permanent. Also, if the gene did insert into a chromosome it would not necessarily be expressed. So this idea basically fizzled out on a technicality. Incidentally, multi-generational SMGT could not be reproduced in other labs making the initial reports suspect.

Well, I really want to see a snake that glows in the dark! So I started thinking – what does a gene need in order to replicate? Well a gene sits on a chromosome and this chromosome needs at least an Origin of Replication, a centromere, and a telomere. When you really want to win the Tour de France you don't send just one cyclist - you send the whole team. So, what if we sent a whole chromosome instead of just a DNA fragment?

Hypothesis: Sperm Mediated Chromosome Transfer (SMCT) – use a sperm to deliver an entire chromosome to the egg.

Go to part 2 to some interesting notes about this hypothesis

- Just a peasant

Photo of two cats - the one on the right is expressing a gene that glows red under UV black light. From Gyeongsang National University in South Korea - video here.