Appendix

Degreesedit

Kinship	Degree of relationship	Genetic overlap
Inbred Strain	not applicable	99%
Identical twins	first-degree	100%
Full sibling	first-degree	50% (2−1)
Parent	first-degree	50% (2−1)
Child	first-degree	50% (2−1)
Half-sibling	second-degree	25% (2−2)
3/4 siblings or sibling-cousin	second-degree	37.5% (3⋅2−3)
Grandparent	second-degree	25% (2−2)
Grandchild	second-degree	25% (2−2)
Aunt/uncle	second-degree	25% (2−2)
Niece/nephew	second-degree	25% (2−2)
Half-aunt/half-uncle	third-degree	12.5% (2−3)
Half-niece/half-nephew	third-degree	12.5% (2−3)
Great grandparent	third-degree	12.5% (2−3)
Great grandchild	third-degree	12.5% (2−3)
Great aunt/great uncle	third-degree	12.5% (2−3)
Great niece/great nephew	third-degree	12.5% (2−3)
First cousin	third-degree	12.5% (2−3)
Double first cousin	second-degree	25% (2−2)
Half-first cousin	fourth-degree	6.25% (2−4)
First cousin once removed	fourth-degree	6.25% (2−4)
Second cousin	fifth-degree	3.125% (2−5)
Double second cousin	fourth-degree	6.25% (2−4)
Triple second cousin	fourth-degree	9.375% (3⋅2−5)
Quadruple second cousin	third-degree	12.5% (2−3)
Third cousin	seventh-degree	0.781% (2−7)
Fourth cousin	ninth-degree	0.20% (2−9)