If you have questions about your family relationships, the most accurate way to get answers is through DNA testing. But when it comes to full- versus half-sibling matches, interpreting test results can be confusing—and the results might vary. To help you understand more about how DNA testing works to determine sibling relationships, the experts at AccuDNA in Saint Louis, MO, explain more about this issue.

A Guide to DNA Testing for Half- & Full-Sibling Relationships

What Is a Half-Sibling?

Half-siblings share one parent only—either a father or a mother. Siblings with the same mother are referred to as uterine or maternal siblings, and those sharing a father are agnate or paternal siblings. Half-siblings are also considered to be second-degree relatives, compared to full siblings, who are first-degree relatives.

Do Half Siblings Share the Same DNA?

You inherit half of your DNA from your mother and half from your father. Full siblings with the same mother and father share about half their DNA with each other due to their common inheritance. Half-siblings who share a mother or father will have about a quarter of their DNA in common depending on factors like the dominance of certain genetic traits in the common parent.

How Can DNA Testing Tell If Someone Is Your Full or Half-Sibling? 

DNA experts compare specific chromosomes to establish genetic relationships. Full siblings who undergo DNA testing can expect to see a high level of overlap between their common genes. Half-siblings will show some commonalities, but the range can vary, and the test may even be inconclusive. In this case, you will need to collect additional DNA samples from other relatives to identify genetic patterns and confirm the relationship.

If you’re looking for answers to a question about sibling relationships, turn to the experienced professionals at AccuDNA. This locally owned and operated facility provides high-accuracy, personalized relationship DNA testing services for a wide range of situations. To find out more about their services, visit their website, or call (314) 845-9997.