x1 is a genetic-familial/'blood' ancestor of x2 by bond/tie/relation/of degree x3.
x2 must be the genetic offspring of x1 or the genetic offspring of someone who is also a ginlazyseldze of x1; trivially, one may consider x1 to be a ginlazydze of themself (x1), and possibly/probably others. See also: kraune, kloje, tseingu, dzena. This is more specific than seldze (x3 is much narrower). This word is equivalent to "se ginlazyseldze".