First Cousins: On average, first cousins share about 12.5% of their DNA, inherited from a common set of grandparents. This is approximate to the amount shared between a person and their own great-grandparent.

Second Cousins: Second cousins share great-grandparents and, on average, have about 3.125% of their DNA in common. This is approximate to the amount shared between a person and their own x3 great-grandparent.

Third Cousins: Third cousins share great-great-grandparents and typically share about 0.78125% of their DNA. This is approximate to the amount shared between a person and their own x5 great-grandparent.

Cousin Removed: A cousin “removed” refers to the degree of separation in the family tree between two individuals. For example, the child of a first cousin is once removed which signifies the difference in generations. Therefore, a first cousin’s grandchild is considered twice removed. Here is a chart to visually depict possible relationships.

Double First Cousins: This occurs when two siblings from one family marry two siblings from another family, and each couple has children. The children are double first cousins, sharing both sets of grandparents. Here is a chart to visually depict this relationship.

Multiple Separate Relationships: Sometimes, individuals might be related in more than one way. It is possible to be second cousins and third cousins at the same time. Community members with deep roots in an area may be fifth and sixth cousins more than ten separate ways.

Duplicate Relationships: It is not uncommon for people to descend from the same ancestor more than once. In any instance where a pair of cousins has married, their children would descend from the same people through both parents several generations back. This means the descendant can have great (etc.) grandparents through different branches who were siblings. For example, here is a chart depicting the relationship between second cousins who have married and had a child.