LeatherBacks
In late 2006 we had an opportunity to import a new line of Leatherback dragons from a private breeder in Italy. These leatherback dragons display minimal tubercles and reduced scale size throughout their body. This form of tubercle reduction is consistent and does not produce "partial" leatherbacks. After communication with Alessandro and working with the Leatherbacks through the last breeding season, we believe that this gene is breeding in an incomplete dominant fashion.The Leatherback dragons display a reduced scalation - between a normally scaled dragon and a scaleless dragon. This indicates that there is a blending of the 2 (normal and scaleless) genes effected - which is visually expressed in the leatherback.
Again, these Leatherback dragons look distinctly different.
To figure out what to expect from this cross a Punnett Square is the tool to use.
With the male being Leatherback and the female being normally scaled your square would look like the following.
Leatherback Male = n S*
Normal Scaled Female = n n
| n |
S* |
|
| n |
nn |
nS* |
| n |
nn |
nS* |
Approximately half of the clutch has the potential to hatch as Leatherbacks. Any animals that do not hatch as Leatherbacks are of the normally scaled trait. This is'nt the exact percentage of each that will hatch out of a given clutch - it is the percentage of probability that each hatchling has to display the desired trait.
Again, when an Italian Leatherback is bred with any normally scaled dragon, the offspring result in approximately 1/2 regular scaled and 1/2 leatherback.
The major advantage to working with this trait is that the dragons which are visibly different from the normal scaled animals and can be easily identified with just a glance. There are no "possible Hets" which means there is no guess-work involved - it is either a Leatherback, or it isnt... And since the Leatherback could be considered for the sake of identification as a 'visible het', this gene can be outcrossed indefinitely through many generations and still be identified easily.
SilkBacks
The Leatherback dragons can be bred together to create an extreme version of itself. These are known as the SilkBack dragons and they are an extreme opposite form of this gene. There is a defined difference between the LeatherBack and Silkback, as Silkback dragons do not have scales or tubercles on their backs or ventral sides. The lateral spines are also absent from the Silkbacks. With the absence of scales, the actual coloration of the animal is much more vibrant.With the male being Leatherback and the female also being Leatherback your square would look like the following.
Breeding two Leatherbacks together will result in a mixed clutch approximately of 25% normals, 25% Silkbacks and 50% Leatherbacks.
Leatherback Male = n S*
Leatherback Female = n S*
| n |
S* |
|
| n |
nn |
nS* |
| S* |
S*n |
S*S* |
With the male being Leatherback and the female being SilkBack your square would look like the following.
Breeding a Leatherback together with a Silkback will result in a mixed clutch approximately of 50% Silkbacks and 50% Leatherbacks.
Leatherback Male = n S*
Silkback Female = S*S*
| n |
S* |
|
| S* |
S*n |
S*S* |
| S* |
S*n |
S*S* |
With the Male being a Silkback and the Female being a normally scaled dragon your square would look like the following.
Breeding a Silkback together with a normal will result in the whole clutch of offspring being Leatherbacks.
Normal Male. = n n
Silkback Female = S*S*
| n |
n |
|
| S* |
S*n |
S*n |
| S* |
S*n |
S*n |
The inheritance of this 'blended' gene is visibly different than the normal or non-scaled dragons. Therefore, no inbreeding is necessary for the reproduction of the Leatherback gene.
Consequently, after sufficiently out-crossing the Leatherbacks into various lines to further extend the available gene pool, it is quite possible to reproduce the Silkback mutation without inbreeding closely at all.
As a final note : The Leatherback/Silkback did not come into being through generation after generation of inbreeding to reduce the scale size on individual animals. This started with 1 individual animal which looked different from its clutchmates. That animal was then raised and bred to an unrelated animal, producing what seemed to be expected ratios for either an Incomplete Dominant (Leatherback/Normal) mutation. The "super", or Silkback, form was identified by breeding 2 siblings that displayed the Leatherback trait. The other Leatherbacks in Alessandro's possession were incorporated into his breeding program and outcrossed to the many other lines in his colony.
For those of you who would like to brush up on genetics, check out The Learning Center at VMS. Excellent site.
N.E.R.D.'s information on reptile genetics is also very extensive and easy to comprehend.