In Prince’s world, there was family and then there was family.

But the law does not necessarily see things that way. And now, Prince’s presumptive heirs argue that the law must take precedence. They filed a joint objection Monday to sharing his mammoth estate with two descendants of Duane Nelson, whom the late musician called his brother but who likely shared no genetic links.

Brianna and Victoria Nelson have argued that genetic links and adoption aren’t the only ways to establish a family relationship under Minnesota law for the purposes of determining “heirship” in probate matters. They say behavioral evidence should be considered.

Brianna Nelson is the daughter of the late Duane J. Nelson, Sr., who died in 2011. Victoria is the daughter of his son, the late Duane Nelson Jr., who was Brianna’s half brother. Duane Jr. died in 2006.

Their attorneys argue in court filings that Prince’s genetic father, the late John L. Nelson, “assumed and embraced his role as Duane’s father and Brianna’s grandfather even though he was not Duane’s biological father and he never formally adopted Duane.” By that reasoning, they argue, Duane Nelson Sr. was Prince’s half brother, making Brianna and Victoria the niece and grandniece of Prince, respectively.

That argument didn’t fly with Prince’s only sister, Tyka Nelson, or his five surviving half-siblings — Omarr Baker, Alfred Jackson, John Nelson, Norrine Nelson and Sharon Nelson — who under Minnesota law stand to share in Prince’s estate because no will has been found. They have been determined to be heirs by Carver County District Judge Kevin Eide, who is overseeing the probate case.

Prince died of an accidental overdose of the painkiller fentanyl on April 21.

Attorneys for Prince’s sister and half-siblings argued that Brianna and Victoria Nelson have no legal avenue in Minnesota to share in the estate. They wrote in a court filing that a family relationship must meet the requirements of the Minnesota Parentage Act or Probate Code to be classified as heirs in cases where no will was left.

Genetics, adoption, assisted reproduction or one of the established presumptions of the Parentage Act can establish a valid parent-child relationship, they wrote. But they say that Brianna and Victoria want Eide to allow their claim to the estate based “entirely on behavioral and anecdotal evidence.”

Lawyers for Prince’s presumptive heirs complain that the dispute is draining the estate’s resources — valued at $100 million to $300 million before taxes. They asked Eide to deny the claims of Brianna and Victoria and halt any additional discovery or evidentiary hearings on the issue.