In the new PNAS paper, the authors report DNA similarities among friends. Apparently, biochemical processes of different friendly organisms have similarities imprinted in their genotypes.
As Cardano wrote in the 16th century, "When several children have the same accidents and fortune, if it be in their childhood, it may be shown by the genitures of their parents; or if in their old age, we may conclude the Nativities of their Parents were so powerful that they assimilate their Nativities between themselves and suit them to the disposition of Children in the Paternal Figure" (aphorism 2.59).
I know numerous examples of puzzling "coincidences" in astrological charts of people forming groups and families. A leader of a group of 10 employees that hires them after short interviews has the same zodiacal sign as three of his subordinates. A family of five has three Scorpios among them, and two children find partners who are born within days from each other. A pregnant woman with Sun in Cancer expects a child under Gemini, but delivery is delayed and delayed, for almost two weeks, until the child is born... with Sun in Cancer.
Modern genetics can explain this by homophilic genotypes. Astrology did this with natal charts, centuries earlier.