The simian crease is one of the listed signs in Down Syndrome which would imply there's some genetic factor at play. My eldest daughter has a simian crease on one hand and the other hand is 'normal'.
Sovereign definition, a monarch; a king, queen, or other supreme ruler. See more.
A monarchy is a form of government in which sovereignty is actually or nominally embodied in one or several individual(s) reigning until death or abdication.They are called the monarchs. In a constitutional monarchy, the monarch is subject to a constitution. 2  The monarch serves as a ceremonial figurehead symbol of national unity and state continuity. 3  The monarch is nominally sovereign but the electorate, through their legislature, exercise (usually limited) political sovereignty.