Half and Full Siblings

When we talk about siblings we refer to brothers and sisters, irrelevant of sex. Siblings can be half siblings and have just one biological parent in common or they can be full siblings and share both biological parents. Half siblings inherit approximately half of their genetic material from each parent and half siblings will share around 25% of their genetic material. Half siblings that have the same biological mother are medically referred to as uterine siblings. If the half siblings share the same father, then they are called agnate siblings.

Full siblings have both biological parents in common and will share 50% of their genetic makeup. The exception to this is identical twins that are always of the same gender and share their entire DNA. When we do relationship DNA tests we can indicate the nature of the relationships between siblings and whether they share common parents. Relationship DNA tests offer a number of sibling DNA tests which are specifically designed for this purpose.

When contacting easyDNA regarding your siblings test it is recommended that you provide information about all the parties available for testing including the mother or any other relatives. You can find more information about understanding the results of your relationship testing by clicking here