Example of a linkage group with 8 markers including 2 ambigous. The figure represents a chromosome with eight markers. Two (M2 and M6) are ambiguous (For M2, the progeny received either the 1stallele of its sire and 2ndallele of its dam, or the 2ndof its sire and 1stof its dam. The nodes are, on the left, the first marker, and on the right, markers M7 and M8. The dark (respectively white) circles represent markers with a known (respectively unknown) grand parental origin.