I'm just now getting a chance to post this here.....since I blogged about it on Cryokid several weeks ago....but it's just so important that I felt it was necessary to mention it here as well.
Saturday, November 28, 2009
Posted by Lindsay
Damian Adams (Donated Generation) and I uncovered the mathematical equations required to determine siblingship -- ie how to take raw DNA profiles and compare two individuals (ideally with their mothers as well) to determine the probability of these two individuals being half-siblings.
While Damian and I are excited about the nerdy aspects of this (actually cracking the code!!), the importance for every other donor conceived adult is what we plan to make of this discovery in the future.
Our goal is to create a web-based database where an offspring can upload their DNA profile (basically your personal results from a paternity and/or siblingship DNA test.....the 15-marker tests) and their results will be scanned against every other person in the database looking for individuals that have a combined siblingship index over 1.0.
The number 1.0 is important, as it is the "threshold" between suggesting non-relatedness and suggesting relatedness. Indexes below 1.0 mean the two individuals are likely non-related, with the smaller the number being more likely that they are not related. Indexes above 1.0 mean the two individuals are likely related with the larger the number being more likely that they are related.
We are proposing a revolutionary project for offspring. One that will contact two individuals if they score over 1.0 on our combined siblingship index. With numbers very close to 1.0 (typically numbers under 10), it is a very grey area and we cannot conclude one way or another if the two individuals are related or not. It may be that both mothers need to be tested, or possibly a company that performs a test on more markers. However, we WILL contact anyone who receives even an inconclusive yet over 1.0 score, and it will be up to those individuals to decide where to go from there.
There are two other projects in the world similar, yet our proposal is seen as a way to fix some of the issues of the other two.
UK DonorLink has been in effect for several years now, where UK offspring and donors can submit their DNA to the database and siblings and/or parent-child relations will be notified. However, recently we've learned they are ONLY contacting matches that are over 99% probability. That means two offspring that receive a very high (and actually conclusive based on legal precedence which states 90% is considered legally acceptable) but not high enough to be 99% probability, are never contacted that such a possibility even exists! We know that siblings have been found with significantly lower probabilities and that denying offspring to knowledge of a possible sibling is continuing the injustice we already suffer from in the first place.
CaBRI is an American non-profit company founded by former donor Kirk Maxey. He has created two projects, Donor Y and Donor X, where offspring and donors can submit their DNA and it will scan their databases for matches. However, the caveat is that because these tests only look at the X and the Y chromosome, siblings can only be found of the same sex. Males inherited their Y chromosome from their biological father. Any male half-sibling would share the exact same Y chromosome, so male-to-male sibling matches can be made. Females inherit one X chromosome from mom and one from the biological father. Thus a female offspring and her mother must be tested and the X chromosome that came from the father would have a sibling match if another female offspring's X chromosome that came from her biological father was the same. However, CaBRI does not have database capabilities to determine siblingship in opposite sex cases, unless the donor has his DNA on record as well. They can do private autosomal DNA tests however those results are not in the database. We want a database that ALL offspring can find ANY sibling possible, regardless of sex.
So that about sums it up. Damian and I are very excited at these prospects and are working diligently to create some sort of automatic database. For the time being however, we would be happy to take any DNA profiles (we strongly suggest also providing mom's DNA as well) and we will manually scan them through our currently very small database. The more offspring to submit their DNA, the more likely we will be finding matches!!
Currently I have been working on a personal project with offspring and donors from Xytex, so please email me if you would like to be included in this as well.
Our methods DO WORK. I found a half-sister through Damian and I's hard work, and I hope to connect many more siblings in the future!!