History of the Tessera Mutation

History of the Tessera Mutation

FIRST, what makes Tesseras so hobby valuable? Other than appearance, the primary (and inherent) value of Tessera-type Corns is their mode of inheritance.  Since they are dominant to wild type, pairing any visual Tessera Type (most are actually visual-hets) to ANY corn snake (other than a Tessera-type) will render approximately 50% visual Tessera mutants in the F1 (first) out-crossed generation.  The results of pairing a Tessera homozygote with ANY corn snake (other than a Tessera-type) will render 100% Tessera mutants.  Homozygote Tesseras are exceedingly rare in the hobby, and, so far there are no visual markers to distinguish a Homozygote from a Visual-het.  THEREFORE, when you see a Tessera, it is much more likely just a Visual-het, even though it is cited and advertised as a Tessera. 

tessera corn snake

History of the Tessera Mutation:

In 2007, Graham Criglow asked KJ Lodrigue to order a 1.2 trio of Striped Motleys that were advertised on one of the popular Online Classified sites - since Graham's job prevented him from personally receiving them at that time.  When they arrived, KJ discovered that they constituted a 2.1 reverse trio (two males and one female) instead of the advertised 1.2 trio (one male and two females).  KJ and Kasi recommended that Graham gift the extra male to me, and that's what Graham did.  Profound thanks to Graham, KJ, and Kasi for that gracious and fortuitous gift.  In 2008, both the Lodrigues and I independently bred our males (Graham's and mine) to novel (unrelated) corns. I produced about 24 TESSERAS (so named by the Lodrigues for the tessellated lateral markings) from over 50 fertile eggs, but since the Lodrigues were in the middle of a career move to another State, they were less fortunate, producing just four non-mutant Okeetee-looking corns.  My Tesseras were produced by the pairing of the male Tessera to three novel female corns (two F1 Locality Okeetees from Chip Bridges Rhett Butler Line and one Okeetee-ish female, Het for Stripe and Amel).  Imagine my surprise in seeing what we thought were nearly flawless Striped Motleys from three different females, only one of which was Het for a recessive pattern mutation?  After the first brood of 50% Tesseras hatched from the female that was het for Stripe and Amel, except for the perfection of pattern, I was not thinking new dominant mutation, but when both wild-type Okeetees produced the same results, it was obvious that a new mutation was discovered.

Upon receiving the reverse trio from the seller in 2007, we all commented on the mutual peculiarity of the phenotypes.  Advertised as Striped Okeetees, they appeared to be the most nearly perfectly Striped Motleys ever seen--in so much as their dorsal stripes were NEARLY contiguous from neck to tail tip (something never before seen in any corn snake pattern mutant) but that was hardly possible if the citation of the genotype of the breeders were true--that they were products of pairing a Striped corn with an Okeetee corn.  How could these descendants of a Striped mutant corn bred to an Okeetee be Motley types, instead of Striped?   They were incorrectly identified as striped mutants?  It is still unclear if those 2.1 Tessera sub-adults were F1s (first familial generation) or F2s (the originator of this line is now out of the hobby and difficult to reach - for clarification).  If these three Tesseras are F1s, my deduction is that the striped corn he used in the original pairing was actually Striped AND Tessera.  Even if those three sub-adults received by KJ and Kasi were F2s , the likelihood of the mutant patriarch being a Striped Tessera is strong.  Since he called the reverse trio STRIPED OKEETEES, it's more likely that their parents were a classically patterned Tessera and an Okeetee, instead of a Striped mutant and Okeetee?

What to expect:

At that early period in the Tessera's resume, we didn't know what phenotypic potentials were possible.  So far, the only genetic feature that is atypical for a corn snake mutation is that many of the non-mutant siblings of Tessera types seem to have enhanced pattern and color features.  So far, I don't see any hybrid markers, since the collateral sibling features to which I refer are - so far - in the realm of improving existing corn snake features (i.e. some non-Tesseras have better, brighter, cleaner, and/or more consistent colors and markings).

In the 100+ Tessera mutants produced by me as of Fall, 2010, I'm seeing the following features:

Presuming that you are breeding a Visual-het--indistinguishable from their homozygote counterpart--the most obvious advantage of having Tesseras in your breeding inventory (aside from their inherent beauty) is that because the mutation is dominantly inherited, 50% of every brood of corns from them will be visual-het Tessera mutants (they will look like homozygote Tesseras, but will only possess one of the paired Tessera gene copies (unless you are fortunate enough to possess a Tessera homozygote).  With most other corn snake mutations--which are recessive to wild type--one must raise all the Het F1 progeny, and won't receive any visual mutants until F2 reproduction (a task that can take four to six years).  In the course of adding Tessera to the myriad current patterns and colors of corns, an entirely new market is now in the making.

Predominantly contiguous dorsal striping is the most unique feature of most Tesseras.  Even when the dorsal stripe is broken, it resumes immediately thereafter (unlike Striped and Motley mutants whose dorsal striping never resumes with any degree of renewal). More than 1/2 of all that have been produced so far have no stripe breaks.  Another 1/4 or so have two to four stripe breaks, and the other 1/4 can have five to 20+ stripe breaks, but those breaks are merely interruptions of the stripe.  When bred to Bloodred types, the dorsal stripe can be more than 50% broken.  Not unlike very good Striped Motleys, many Tesseras have an interruption of stripe at the girdle (anatomical location - polar to the cloaca), but unlike Striped and Motley mutants, the dorsal stripe almost always continues to the tail tip thereafter.  Thus far, fully striped Tesseras have been produced from parents with some-to-many dorsal stripe breaks.  Hence, broken-striped Tesseras can produce fully striped striped Tesseras, even though their stripe is broken.  Incidentally, none of the original 2.1 original Tesseras in this line had complete dorsal striping, but many of their progeny and grand progeny do.

More than 2/3 of the Tesseras produced by me so far have atypically large amounts of black pigment in their non-ventral pattern -- a feature roughly 1% of all Striped and Motley mutants have demonstrated to date.  Less than 1/4 of all Tesseras produced by me have little to no black in their markings, and these are mostly Striped Tesseras.

tessera bellies

The belly patterns are all over the charts.  A precious few have enough belly checkering to qualify them as wild-type common corns -- until you flip them over to see their mutant pattern elsewhere.  About 1/3 of them have roughly 15% to 30% of the volume of checkering seen in wild-types, and about 1/3 or more have virtually no belly checkering at all.  Some of the ones with NO belly checkering have organized strings of black markings running the length of both sides of the belly, along the ventral keel.

Tessera having essentially grafted another entire branch on the already sprawling corn snake family tree, we think the Tessera mutation will offer genetic flexibility never before possible; mainly in the realm of making Stripe and Motley types without losing the black (or white in albinos).  A strong genetic function of Motley and Striped mutants in corns is reduction or exclusion of black. Imagine all the current colors of corns infused with the Tessera, Striped Tessera, and Motley Tessera patterns?

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