Empty Back

Introducing the ACR Empty Back Project

The Empty Back project is one I've been somewhat-quietly working with over the past several seasons.  As you may expect with an operation of this size, the gene slowly leaked from my collection into those of my customers (and the customers of my customers) before I realized exactly what was going on with it - sometimes the hets were obvious, but sometimes not. It wasn't until the Supers started cropping up that I realized we had a mutation and not just a trait.

Going further back, I have probably been producing het EB's for a very long time in very small numbers, but it didn't seem to catch my attention up until about 10-12 years (and nearly as many generations) after the last geckos I bought...maybe 2017 or so.  I had some geckos where I just happened to pair EB with something that had an effect I liked...on those, I liked how the pinning tended to run to the head on many of the Harry line geckos that I made with it.  I hadn't really taken note that it was diminishing the dorsal pattern because those geckos only had orange on the dorsal anyway (not cream). I originally labeled those with the code "P2H" (Pinning to Head) and held all of them back until I started mixing it with creamy-dorsal geckos in order to put it on other base colors.  Eventually I started outcrossing and getting geckos where it didn't really do much for their appearance except add some dark figure to the creamy dorsal....little did I know these were hets for something more extreme.  Other times I sold hets completely unaware they even had the trait because the pinning wasn't going up to the head like it did on the ones from my Harry/Soft line.

Where did it come from originally?

From what I can tell, this gene in my collection originated with geckos I got from Allen Repashy in the early to mid-2000's, which should be no surprise.  Talks with other industry veterans have confirmed that Allen had and sold Empty Backs back then, prior to getting out of the gecko breeding business in the late 2000's. 

Allen is who originally imported and then later produced the highest quality crested geckos that anyone had access to in those days. Nothing else came close. Structure, pattern, you name it - his were on another level.  Without the founding geckos that I acquired from Allen, we would have nothing like the structure or size we have in my collection today.  I would also lack key projects such as Soft Scale, the entire Harry line (and the shaggy structure I got from it) and this one thing I named "Tangerine pigment" in 2004.  Now it's confirmed Empty Back can be added to that list.

It's unknown if Allen's original Empty Backs are still with his old collection today and obviously,  there's no telling how many EB's there would have been coming out that collection before it was sold off.  As long as it took for the Super EB to be discovered, I have to think it probably wasn't very many.

Empty Back Genetics

Empty back is a straightforward incomplete dominant gene, meaning the heterozygous gene carriers are visually distinct and there is a visibly different homozygous or "Super" form. 

That said, EB is not always so easy to see in het form because the dorsal can still be influenced - or even obscured/masked - by other strong pattern elements, such as a heavy cream dorsal or Lilly White's dorsal.  Fortunately, the Super EB is much more extreme and does not seem to be masked or influenced nearly as much.

Because the presence of EB can be so difficult to discern in heterozygous form, there was briefly some talk privately amongst breeders about the idea of calling EB a recessive gene because of how difficult some of the hets can be to pick out. I personally have produced dozens of Super EB's without knowing the adults were carrying EB at all, so it was certainly something to think about.

You will see me refer to these geckos in the following ways, in order to make things less confusing.

  • Possible Het EB: One of the parents is a Visual Het Empty Back, but we can't tell for sure if the gecko is a Het because of other genes making it hard to determine. Sometimes hets aren't visually obvious. Lilly Whites and other creamy-back combos are good examples.  Phantoms can also be difficult.
  • Visual Het EB: I can plainly see that it's the heterozygous form of the Empty Back.
  • Super EB: Most of the back is showing base color, obviously not a Het EB, but a Super.
  • Possible Super EB: This is when we know the EB gene is present, but we can't tell for sure if it's a Super because another gene or creamy dorsal pattern is making it uncertain.  These geckos are only considered Possible Supers until you breed them and find out if they are or aren't.  As we get more experienced with the project, we'll be able to better tell by just looking at them.

*This IS NOT technically correct terminology, but we are working with multi-gene animals and the level of confusion is greatly reduced when I have talked to people about the EB project in these more relatable terms.  If you see someone using different terminology, they're probably using technically correct terminology and that's perfectly fine too.  I figure if you know the proper terminology, the above won't be confusing at all. :-)

Genetic Compatibility with Other Lines

Spoiler Alert: I would almost bet my collection that they're all originally descended from the Repashy lineage (though most probably came by way of my collection) and should all be compatible.

While there theoretically could be another similar EB gene floating around, which was my initial feeling, I highly doubt that theory now, after seeing how widely variable this gene is in my own collection. 

One thing to consider is that my EB's would have been isolated and developed (however accidentally at first) independently for 16+ years now, whereas Empties descended from outside Repashy stock may have been crossed into all kinds of stuff over the years. The ones that came directly from Allen's collection through other breeders would have to look somewhat different, given how many generations we have developed here without any outside influence.

Empty Backs in Asia and Europe
To save you the trouble of confirming with me, I have sold numerous visual het EB's into the Asian market (Hong Kong, Korea and Japan) and I am all but sure it also got into Europe in our Hamm shipments.  EB's from overseas should also be compatible.

Here's the bottom line, if you're a buyer worried about compatibility between lines.
I honestly believe most of the EB's on the market are the exact same gene (for all the reasons listed above).  The important thing to find out is if the line you're buying is known to produce a Super Empty Back version. If so, and the Super looks familiar, it would almost have to be compatible. If not, or there's not a confirmed Super form, then you may want to do more research before you buy.