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.
The noun KINGDOM has 6 senses: 1. a domain in which something is dominant. 2. a country with a king as head of state. 3. the domain ruled by a king or queen. 4. a monarchy with a king or queen as head of state. 5. the highest taxonomic group into which organisms are grouped; one of five biological categories: Monera or Protoctista or Plantae or Fungi or Animalia. 6. a basic group of natural objects. Familiarity information: KINGDOM used as a noun is common.