Duisburg is a German city in the western part of the Ruhr Area in North Rhine-Westphalia
Johan’s parents were ALEXANDER BOCHER x SIBILLA NN
x 1670 SIBILLA van der UPWHICH, * 1620 † 1687 d.v. Dirk van der Upwich en Catharina Swem. Dirk was die burgermeester van Rees, Germany. 
Katoliek en beroep “Keurvorstelijk Wandgraaf te Kleef” (die kollege het nuwe pouse vir die kerk verkies) 
“It appears that Johan was a Catholic as his occupation was “Keurvorstelijk Wandgraaf te Kleef”. This I take to mean that he was a member of the College. He was Catholic and part of the “Keurvorstelijk Wandgraaf te Kleef” (the college that had the power to elect new popes for the church”
It may be possible to confirm family relationships with Johannis by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Johannis: