1. What is Autosomal DNA?

Autosomal DNA is inherited from both parents and contains genetic information from all ancestors (not just direct maternal or paternal lines). The amount of shared autosomal DNA (measured in centiMorgans or cM) helps determine genetic relationships between individuals.

2. How Does the Calculator Work?

The calculator uses a simple summation formula:

Where:

• \( \text{autosomal\_cM} \) — Array of centiMorgan values from DNA segments
• \( \sum \) — Summation of all values

Explanation: The calculator sums all the shared DNA segments (in cM) to give the total amount of shared autosomal DNA between two individuals.

3. Importance of Shared cM Calculation

Details: The total shared cM helps estimate how closely related two individuals are. Different relationship types (siblings, cousins, etc.) typically share characteristic amounts of DNA.

4. Using the Calculator

Tips: Enter all shared autosomal DNA segments as comma-separated values (e.g., "12.5, 8.2, 35.7"). The calculator will sum all valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a centiMorgan (cM)?
A: A unit of genetic linkage that represents the likelihood of recombination between two markers. Higher cM values indicate closer genetic relationships.

Q2: How much DNA do close relatives share?
A: Parent/child share ~3400 cM, full siblings ~2600 cM, first cousins ~850 cM, second cousins ~225 cM.

Q3: What if I have segments with 0 cM?
A: These are typically not included in relationship calculations as they don't represent shared DNA.

Q4: Can this determine exact relationships?
A: While shared cM can suggest possible relationships, additional information is needed to confirm exact relationships.

Q5: How accurate are these calculations?
A: The calculation is mathematically precise, but relationship predictions based on cM have probability ranges.