Table of Contents
- 1 What percentage of shared DNA is significant?
- 2 What percentage of DNA do you share with half siblings?
- 3 What percentage is a good DNA match?
- 4 Do half brothers and sisters share the same DNA?
- 5 How many cM do full siblings share?
- 6 What percentage of DNA do you share with your cousins?
- 7 How much of your DNA do you share with your nephew?
- 8 Where can I find the percentage of autosomal DNA shared by relatives?
Percent DNA Shared by Relationship
| Relationship | Average \% DNA Shared | Range |
|---|---|---|
| Identical Twin | 100\% | N/A |
| Parent / Child Full Sibling | 50\% | Varies by specific relationship |
| Grandparent / Grandchild Aunt / Uncle Niece / Nephew Half Sibling | 25\% | Varies by specific relationship |
| 1st Cousin | 12.5\% | 7.31\% – 13.8\% |
25 percent
Half siblings share 25 percent of their DNA. 50 percent of each half sibling’s DNA comes from the shared parent, and they inherited about half of the same DNA from that parent as one another.
How many cM do you share with a half aunt?
DNA is inherited rather randomly so you could share a bit more or a bit less with a sibling. A whole aunt/uncle will share around 25\% with a niece/nephew around 1800cM and a half aunt/uncle around 12.5\% making it around 900cM.
What percentage is a good DNA match?
Average Percent DNA Shared Between Relatives
| Relationship | Average \% DNA Shared |
|---|---|
| Full Sibling | 50\% |
| Grandparent / Grandchild Aunt / Uncle Niece / Nephew Half Sibling | 25\% |
| 1st Cousin Great-grandparent Great-grandchild Great-Uncle / Aunt Great Nephew / Niece | 12.5\% |
| 1st Cousin once removed Half first cousin | 6.25\% |
The usual satisfying genetics answer right? It turns out that half-siblings share 25\% of their DNA on average. But this is only an average. Because of how DNA is passed down from parents to children, some half-siblings will share more than 25\% of their DNA and some will share less.
What percentage of DNA do aunts and nieces share?
Siblings share around 50\% of their DNA while half siblings only share around 25\%. The amount shared is usually expressed in something called centimorgans. Full siblings tend to share around 3500 centimorgans while half siblings share closer to 1750. You can find those numbers at the bottom of the graphic image.
Average Percent DNA Shared Between Relatives Relationship Average \% DNA Shared Range Grandparent / Grandchild Aunt / Uncle Ni 25\% 17\% – 34\% 1st Cousin Great-grandparent Great-grand 12.5\% 4\% – 23\% 1st Cousin once removed Half first cousi 6.25\% 2\% – 11.5\% 2nd Cousin 3.13\% 2\% – 6\%
What percentage of DNA do you share with your great-grandparents?
Average Percent DNA Shared Between Relatives Relationship Average \% DNA Shared Range 1st Cousin Great-grandparent Great-grand 12.5\% 4\% – 23\% 1st Cousin once removed Half first cousi 6.25\% 2\% – 11.5\% 2nd Cousin 3.13\% 2\% – 6\% 2nd Cousin once removed Half second cous 1.5\% 0.6\% – 2.5\%
We were both tested and it shows us sharing 16\% of our DNA which the test says makes us first cousins. You could definitely share less than 25\% of your DNA. In fact, most nephews share a bit more or less than 25\% of their DNA with their aunts or uncles.
You can find a list of the average percent of autosomal DNA shared by close relatives on the International Society of Genetic Genealogy (ISOGG) website. [1] The observed ranges by known relationship reported by 23andMe customers on the International Society of Genetic Genealogy (ISOGG) website.