DNA Connections
It may be possible to confirm family relationships with Isaac by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree:
Greetings! Isaak Schalk van der Merwe & Cecelia Janse van Rensburg are missing a son: Nicolaas. I see someone posted a link to the info for Nicolaas on Family Search a couple of years ago.
Nicolaas is also listed in the printed version of GISA's Geslagregister (Vol M, p. 564). In that register he is b2c11d6, B. 7/4/1747, baptized 7/5/1747, married 12/2/1769 to Aletta van der Merwe, daughter of Hendrik van der Merwe and Aletta Keyser.
I haven't found death dates or hints, yet. The couple only had 2 children (in 1772 and 1774). Nicolaas' brother Carel took over the registration of a loan farm from Nicolaas in 1785. I have yet to find payment records on the farm between 1778 and 1785. It's possible Nicolaas died during that period.
Please add Maria as daughter to this couple (van der Merwe-3749) "South Africa, Dutch Reformed Church Registers (Cape Town Archives), 1660-1970 ," database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:3Q9M-CSV8-WTL1?cc=1478678 : 21 July 2022), > image 1 of 1; State Archives, Cape Province.
Van Der Merwe-1867 and Van der Merwe-794 appear to represent the same person because: Duplicate. Van_der_Merwe-794 already existed. I'll do the final integration of the bio after the merge, thanks!
Van Der Merwe-1656 and Van der Merwe-794 appear to represent the same person because: Clear duplicate. I'll do the final integration of the bio after the merge, thanks!
Van der Merwe-516 and Van der Merwe-794 appear to represent the same person because: Same data (name, year of brth) Van_der_Merwe-794 has the more correct spelling of the LNAB (lower case 'v' for van der Merwe.)