A strong asymmetric distribution of martensitic variants in non-modulated NiMnGa single crystals with respect to austenite is produced during martensitic transformation. A cubic-to-tetragonal transformation occurs with 24 possible variants divided into two groups. The first group with a misorientation of about 6A degrees is composed of the so-called major variants separated by inter-plate boundaries, while the latter comprises minor variants with misorientation of 12.2A degrees. The 6A degrees rotation associated with major variants can also be observed at each inclination point where conjugation boundaries (CBs) occurs. The removal of CBs straightens out the inclined inter-plate boundaries confirming the Mullner-King mechanism.