Sibling DNA Testing
DNA siblingship tests determine the statistical probability of whether siblings (brothers and sisters) share the same two parents or not. The cost of the DNA testing service includes two siblings, but you may add more as needed; for instance a third sibling.
When the issue of siblingship is in question, the recommended method to determine whether individuals are true biological siblings is to test their parents. In situations where the alleged parents are unavailable for testing, a DNA siblingship test can be performed to analyze the relationship of biological siblings. Including one common parent greatly increases the accuracy of this type of analysis and is recommended if at all possible.
Unlike a paternity test which will always provide a conclusive result, siblingship tests are different. When a siblingship test is conducted, the DNA laboratory will determine the genetic profile of the alleged siblings. Based on the type of genetic material inherited by each sibling, a siblingship DNA index is determined. If the siblingship DNA index is less than 1.00, this indicates non-relatedness. If the siblingship DNA index is greater than 1.00, this indicates that the two tested individuals are more likely to be true biological siblings. The higher the value of the siblingship DNA index, the greater the likelihood that the two individuals are true biological siblings. To analyze the possibility that the siblings share only one common parent versus two common parents (mother and father), a half siblingship DNA index is obtained. The ratio of the half siblingship DNA index versus the full siblingship DNA index would provide you with an idea of whether the two individuals are more likely to share only one common parent (e.g. mother only) or two common parents (mother and alleged father).
Our siblingship tests are preformed using what's known as an "All-vs-All" methodology. For example, if you have two siblings, Alice and Bob, one report will be generated which details the relationship between Alice and Bob. With three siblings you would receive 3 reports which describe the relationships between: Alice & Bob, Alice & Charlie and Bob & Charlie. Four siblings would yield 6 reports: Alice & Bob, Alice & Charlie, Alice & David, Bob & Charlie, Bob & David, and Charlie & David. The amount of reports would subsequently grow exponentially. If you have any questions regarding these reports, please feel free to contact us.
Please note: In some cases, a Y-STR DNA Test can provide more conclusive results for males determining common DNA lineage.
Step 1: Review shipping information
Please review the following important information:
All orders are shipped in plain, confidential packaging. There is nothing on our return address or packages to indicate the nature of the product inside!
For shipping in the continental U.S.
- All orders include a pre-paid addressed return mailer OVERNIGHT FedEx for NO EXTRA CHARGE
- You may choose how you want your kit sent to you. US Mail will take approximately 7-10 Days. For faster delivery of your kit, you may choose Priority Mail or overnight FedEx options (FedEx requires a street address and telephone number)
For shipping outside of the continental U.S: Orders to Canada, Mexico, Hawaii, Alaska, Puerto Rico and recognized US territories can be shipped by mail or FedEx but may not contain a prepaid FedEx return package, depending on location. For INTERNATIONAL orders please call or e-mail for shipping and handling charges.
When orders are shipped: Orders received* Monday through Thursday by 12 noon Mountain Time will be shipped that day; if you choose FedEx overnight you will receive the kit the following day. Orders placed on Fridays for FedEx shipment can be slotted for Saturday delivery (if service is available in your area), otherwise you will receive your shipment the following Monday. GTL does not ship or receive on weekends and most federal holidays.
* Although you may place your order before noon, GTL may not receive the order notification for several hours.
Step 2: Select a DNA test
Please Note: All orders include a pre-paid addressed return overnight FedEx mailer.
Click here for instructions to test parties in multiple locations.
Rush Analysis Options
- 24-Hour Release: $400
No more than 24 business hours from receipt of samples - Next Day Release: $175
By close of business on next business day following receipt of samples
- Second Day Release: $125
By close of business on 2nd business day following receipt of samples - Third Day Release: $75
By close of business on 3rd business day following receipt of samples
Review additional information
Information concerning how samples are taken, the difference between legal and informational testing, buccal versus "pin-prick" sample collection, and more is available and should be reviewed.
Our Refund Policy
Samples must be submitted within 3 months of case initiation or the case will be closed. Refunds will be issued only if applied for within 15 days of the order date. Refunds for orders involving test kits only will not be issued. Full details on our refund policy can be found here.
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