From day zero, implemented “genes” on all rare dragons or higher can receive a gene 
: randomly.
The genes are:
- Simple gene (0.5% chance to get it): Increase 5% one base stat (Cunning, Strength, Endurance)
- Compounded Gene (0.1%): +5 in two stats.
- Shenlong Gene (0.01%): +5% in everything.
The genes can be pass between rarities if you use the dragon with genes as the main dragon in a merge.
Do you imagine a mythical dragon with four genes? 
You will be able to check the genes before marketplace release. It’s active, if you hatched an egg, you could have one gene.