 If they are related, the number of markers tested and the number of matches at those markers determines the range of generations until their most recent common ancestor (MRCA).If the two tests match on 37 markers, there is a 90% probability that the MRCA was less than five generations ago and a 95% probability that the MRCA was less than eight generations ago.A Y-DNA test ranges from 10 to 111 markers on the Y chromosome.