[ericthered]

using genetic Assays to determine an heir would be interesting. You have "Royal Genes", where parts of the monarch's genetics are considered more or less royal. The individual with the most "royal" genetics is the heir. This will usually be a descendant of the current monarch, but order of birth won't matter. The "royalness" of the spouse will matter, as will possibly the gender of the prospective heir, if any genes are on the X or Y chromosome*. Cadet branches of the house probably don't have as much royal genetic material, but they're not completely out of the running.


Also, this unfortunately encourages a certain level of incest. Not that cousin-marrying is particularly uncommon in the annals of royalty.


The determination of the base set of genes is an interesting question. It could be the genome of a single individual (who had better be a nation hero or founder) or an "ideal" genome built from study. Or it could just be the genome of the current monarch.



* If any royal genes are on the Y chromosomes, then the sons of a king have an advantage. If any are on X chromosomes then the daughters of queens have an advantage -- but the X advantage gradually fades.