Jirí Louda and Michael MacLagan, Lines of Succession: Heraldry of the Royal Families of Europe, 2nd edition (London, U.K.: Little, Brown and Company, 1999), table 117. House of Braganza ISBN 0-316-84820-4.
It may be possible to confirm family relationships with João VI by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
However, there are no known yDNA test-takers in his direct paternal line.
Mitochondrial DNA test-takers in the direct maternal line: