Two Sisters Took DNA Tests

choi

Amy Dockser Marcus, Two Sisters Took DNA Tests and Rocked Their Family; With genetic testing, confidences are almost impossible to keep. Wall Street Journal, Feb 2, 2019 (front page).
https://www.wsj.com/articles/two ... -family-11549037904
https://www.msn.com/en-us/lifest ... ly-apart/ar-BBT32uH

My comment:
(a) The report is locked behind WSJ paywall.
(b) "Sonny and Brina Hurwitz raised a family in Boston." On the surface, the couple (now deceased) had two daughters and two sons.

Horwitz  or Hurwitz are variants of Horowitz.
https://en.wikipedia.org/wiki/Horowitz
(c) Dana Dolvin Sr. Google +, undated.
https://plus.google.com/112829291626690817236

One can click at the photo to enlarge it. It appears to me that children of black-white couples vary greatly in skin colors and appearances.
(d) "Siblings share around half their DNA. Half-siblings share a quarter, and first cousins, on average, share 12.5%."
(i) The key is "around." A human has 23 pairs of chromosomes (22 autosomal and one sex).
(ii) In theory, a parent must share about 50% of DNA with his or her biological children -- "about" taking sex chromosome into consideration.
(iii) Theoretically a father can one in each pair of autosomal chromosome to one son and the other of the same pair to another son (a father has to give hand down X chromosome to a daughter and Y chromosome to a son); hence two brothers of the same parents in theory shares DNA from 4.3% (ie, 1/ 23) to 100% -- each figure with its own probability (it will be a normal distribution peaking at 50%). Brother and sister of the same parents share DNA 0% to 95.7% (22 /23).  Therefore in organ donation, a sibling may (or may not) be a better match than his/her parent or child.
(iv) Thus when one encounters related DNA in the search, to ascertain relationship between the two, one has to construct a family tree (until the two share the same ancestor). That is criminologists have been doing.