How is Queen Charlotte Sophia of England related to Margarita de Castro y Sousa?

Question

How is Queen Charlotte Sophia of England (1744 - 1818) related to Margarita de Castro y Sousa, member of the black branch of the Portuguese royal house? Was Margarita de Castro y Sousa a great, great.... grandmother or aunt or even cousin of the queen? I'm very courious!

Answer 1

Add to Paco's excellent answer the fact that Margarita de Castro y Sousa is described as a "Moor". The Moors of North Africa, who in the Middle Ages mixed a good deal with the peoples of Portugal and Spain, are generally Arabs and Berbers, who are not "black" as in "central or south African".

Answer 2

= I see the following reference in the source.

"Six different lines can be traced from English Queen Charlotte back to Margarita de Castro y Sousa, in a gene pool which because of royal inbreeding was already minuscule, thus explaining the Queen's unmistakable African appearance."

  None of these lines are explicitely traced.

  The time frames that they are discussing could be as many as a dozen generations. For instance James II, King of Scots was born in 1430  and George III was born in 1738 and they differ by 11 generations (direct line to Elizabeth II).

  In comparison, several de Sousas had in fact traveled to the Netherlands when their cousin, the Princess Isabella went there to marry the Grand Duke, Philip the Good of Burgundy in the year 1429. Whereas Queen Charlotte was born in 1738.