Anyone who converts is a “real Jew.” Abraham and Sarah were the first “converts.”
But the whole study is nonsense.
There are ample studies that show the Cohen line (Levitical priests) where ever they are -— Ashkenazi, Persian/Mizrahi, Sephardic, share the same paternal Y chromosome.
Similarly, plenty of studies that show close genetic relations with -— ick -— our arab neighbors.
That makes sense seeing that Jews and Arabs are all descended from Abraham.