The World Leader in Private DNA Testing

As part of DDC’s commitment to provide the most comprehensive relationship testing in the industry, our laboratory has been investigating additional DNA markers that can be used to analyze complex relationship cases. To complement the standard set of STR markers that are routinely used in paternity testing, DDC scientists have recently been undertaking research and development on non-autosomal markers.

An autosome is a chromosome that is not a sex chromosome. In humans, most of the DNA is in the form of 46 chromosomes: 22 pairs of autosomes and the sex chromosomes X and Y. DNA markers found on the X and Y chromosomes are called non-autosomal markers. Additionally, markers on mitochondrial DNA (mtDNA), which is found outside the nucleus, comprise the third type of non-autosomal markers our scientists are studying for possible use in complex relationship testing cases.

The non-autosomal markers provide different information from the standard STR markers because of their unique inheritance patterns. Y chromosomes are passed down only from father to son; mtDNA is passed from a mother to all of her children; and a father passes the same X chromosome to all of his daughters. Therefore, non-autosomal markers can prove very useful when additional genetic information is needed to resolve siblingship, grandparentage, and genetic reconstruction cases.

In a siblingship test, for example, females with the same father will inherit the father’s only X chromosome, and therefore his X chromosome markers will be present in both their profiles. The test becomes even more powerful when the mother is tested, and her X chromosome markers can be subtracted from the siblings’ profiles.

The results of our scientists’ study on X chromosome markers and their possible use in solving complex family relationship cases will be presented to other DNA researchers during the upcoming 19th International Symposium on Human Identification. For more information about DDC’s DNA testing services, please visit our DNA Testing page.

This entry was posted on Tuesday, August 26th, 2008 at 2:09 pm and is filed under DNA Paternity Testing. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.