Note that the first new crossover point divides the grandparent 1 segment into two segments, one for each parent of grandparent 1. On the other hand, the second crossover point is separating two segments from different parents of the grandparents. These two parents, labeled Ggp2 and Ggp3 are not related to each other by marriage or otherwise. So some adjacent segments may be for husband and wife; and some may be for distant, unrelated ancestors.