Science Archives - Page 14 of 15

Testing “Brothers and Sisters” for Paternity

by HOMEDNA on 12/08/2008

The ABC show “Brothers and Sisters” once aired an episode in which the two-year-old daughter of Tommy Walker needed a liver transplant. In an earlier episode, when it was discovered Tommy was not able to father children, he asked his two brothers to become sperm donors so that he and his wife could have a child. Since the liver transplant needed to come from the actual father, it was time to find out which of the two brothers was the biological father.

This brings up two often-asked questions:

How difficult is it to determine the paternity of a child when two fathers are closely-related (brothers)? Does testing two brothers decrease the accuracy or probability of the test?

The truth is DNA testing is very accurate and, unless the brothers are identical twins, the test will accurately reveal which one is the father. The biological father’s profile must match the child at ALL locations (loci) tested: usually 15 markers. It’s extremely unlikely that a brother would match a niece at all loci, unless he’s an identical twin to the brother. In that case their genetic profiles will be exactly the same and you wouldn’t be able to tell which one was the father.

In cases like this, we recommend testing both brothers (both alleged fathers) and including the biological mother in the test. By including the mother’s DNA, we can identify which markers in the child’s DNA came from mom and focus on the DNA that must have come from dad. If both brothers are tested with the biological mother, one will emerge as the biological father without question.

Any two people tested, even if unrelated, will likely share at least some markers in common, but a biological father and child will share all markers tested. Including the mother, testing additional markers or loci if needed and testing the other brother will identify more mismatches between the uncle and child and show stronger matches between father and child.

Follow us on Facebook and Twitter! If you have questions about paternity tests or other DNA testing services, please contact our Client Support Center at 888-404-4363, Mon-Fri from 9 AM to 6 PM Eastern Time. Our friendly, expert representatives are ready and happy to help. Get answers anytime by visiting our Help Center.

Are my Twins Identical?

by HOMEDNA on 10/02/2008

There are many anxious parents who have just had twins. They look closely at every feature and contemplate, “Are they identical or not?” Early in the childrens’ lives it may be difficult to tell them apart, but does this really mean they are identical twins or just share very similar features?

Identical twins have exactly the same DNA profiles and a simple DNA test can put all the questions to rest. The profiles for fraternal twins are not exactly the same: instead, they indicate a full-sibling relationship. The lab fee for this test is just $159. You will simply collect a DNA sample from each child using cheek swabs and send the samples to the lab for testing.

The test usually takes five(5) days once samples are received at the lab. So if you have questions about your own twins or if you are a twin yourself and you’re not sure you’re identical to your sibling, call us at 888-404-4363 to set up a test.

What is a Locus and What Does it Have to Do with my DNA Test Results?

by HOMEDNA on 09/26/2008

Locus (plural: loci) is a term used for the DNA markers that are tested and reported on your DNA Testing results. On each report there are generally sixteen markers displayed, fifteen of which are used to help determine your DNA Test results. The names of these loci are listed on the report. An example of one is D2S1338. Each person has two genes at each marker. On your DNA Test result you will sometimes note that there is only one number listed. This means that at this marker a person has two of the same. For example, if at the D2S1338 a person has two 8s the report will only show that gene once.

In the case of a DNA Paternity Test, the alleged father must match at least one of these numbers at each of the fifteen markers. Without matches at each position he may be excluded as the biological father of the child. Having the biological mother included with each DNA test will strengthen the results of your test.

The last marker on a DNA Test is the AMEL (short for amelogenin) gene. This is the gene that indicates a person gender. This is not generally related to the actual results of a DNA Test.

If you have questions about your results and what they mean, feel free to call the IDENTIGENE client support team at 888-404-4363.

Follow us on Facebook and Twitter! If you have questions about paternity tests or other DNA testing services, please contact our Client Support Center at 888-404-4363, Mon-Fri from 9 AM to 6 PM Eastern Time. Our friendly, expert representatives are ready and happy to help. Get answers anytime by visiting our Help Center.

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