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.
Smith's Bible Dictionary. properly the sovereign or governor of the fourth part of a country. (Matthew 14:1; Luke 3:1; 9:7; Acts 13:1) The title was, however, often applied to any one who governed a Roman province, of whatever size. The title of king was sometimes assigned to a tetrarch. (Matthew 14:9; Mark 6:14,22)