CHIMERISM – A THREAT TO THE INFALLIBILITY OF DNA TESTING?
I don’t know about any of you, but I am a CSI fiend! I love CSI New York and Las Vegas. I watch CSI NY because I love the characters and the storylines and I love CSI Las Vegas because of the emphasis on the science.
One story in particular really blew my mind. CSI LV a couple of years ago featured the story of a woman who had been brutally attacked and made a positive identification of the man who did it. When the team arrested the suspect and took his DNA, however, it didn’t match the DNA they found on the woman. She was adamant that the man she had identified WAS her attacker, but the crime lab told her that the DNA evidence said otherwise. It turned out that the man was indeed the one that attacked her. But why didn’t the DNA confirm this?

The man in question was a chimera. A chimera is a man or woman who has two completely different DNA strands in different parts of their body; you are supposed to have only one DNA code throughout your system. In the case on CSI the man had a twin brother who had died in his mother’s womb, but the DNA from the dead twin made its way into the living twin’s body. This man knew that he was a chimera and tried to use this to commit the perfect crime; i.e. he could leave all the trace evidence he wanted because the DNA discovered would be that of his dead twin, not his.

On the Discovery Channel in February, they aired a documentary about chimeras which was absolutely fascinating.

The most interesting case was that of a woman who needed a kidney transplant. The doctors tested her immediate family members to see if any of them could be a donor; the doctors told the woman their tests showed her sons were not her biological children. The woman was understandably baffled by this revelation. After ruling out the possibility that all three of her children had been switched at birth, a team of doctors took up the case to find out what was going on. Test after test confirmed that she was not the mother of her children. In fact, DNA tests proved that her husband and his brother were the biological parents of her children!!!!

After two years of testing, the doctors discovered the woman was a chimera. They took DNA from her ovaries, hair, and some of her glands and they finally found the DNA strand that matched that of her children.

There are 40 recorded cases of chimerism world wide. In those cases, there are signs, both subtle and stark, that they have the condition. In one case the person’s skin had very distinct light and dark chequered markings, in another case the body was divided down the middle by a line; one side was light coloured the other side was dark. There are other common indicators such as eyes of two different colours, or multicoloured hair. But in the case of the women on the documentary, they had no such symptoms. NOTHING marked them out as different in any way at all.

A person can be a chimera and have absolutely no clue about it. The woman in this case concurred that had she not needed a transplant, she would have gone to her grave never knowing she was a chimera. This was a point the doctors picked up – simply because there are 40 known cases of chimerism it doesn’t translate that only 40 chimeras exist. Because so little is known about this condition it is impossible to give any kind of indication as to how many other chimeras there may be. Chimerism is so rare that it is not known how to treat it or how to prevent it from happening.

The viability of using DNA as a 100% proof positive or negative catchall was called into question. In the cases on the documentary, DNA evidence was completely wrong. The fallibility of DNA testing was seen for the first time. If a person knew they had the condition they could, as the character in CSI Las Vegas did, use this knowledge in a wicked way thereby making a mockery of a once failsafe system. If a father wanted proof that the children his partner had were his, and he was a chimera and didn’t know it, DNA would say he wasn’t the father, implying that the woman had been unfaithful!! What a nightmare!!

Interesting isn’t it?

Goodbye to Toxic Relationships

“Belinda!” the familiar voice trilled on the other end of the phone. “How are you? I haven’t spoken to you for ages. With you it was a case of out of sight out of mind. Sorry!”

What a nasty thing to say, I thought. That comment was the final straw; after nearly an hour of *Tara twittering on about her new life with her new husband, I hung up and put and end to what was without doubt the most toxic relationship I’d ever had.

Tara Bellingham. What a mistake that friendship was! I blame myself for not kicking her out of my life sooner. I’d been meaning to do it for years but never did. At the time I was not a confrontational person and consequently I never challenged her pompous and self righteous ways.

At school Tara had been the stereotypical unattractive girl that longed to be part of the in-crowd, but realising that would never happen she contented herself with riding on their coat tails. She befriended the pretty girls who were going out with the hottest guys in school so that she could be as close as possible to the lifestyle that was completely out of her grasp.
All her life Tara longed to be like these girls; popular, slim, pretty and in great demand. The slim thing never happened but her brilliant mind propelled her into the inner circles of many influential groups. And boy, did she love to let you know that she had arrived! People were always coming to her for advice of some kind and she never passed up an opportunity to show how much she knew in comparison to her lesser educated companions. “Phlegm isn’t biodegradable,” was one of her gems, or “Tara's 110 Craptastic Facts”, as I called such meaningless revelations.

I used to have such contempt for women who stayed with abusive partners. “Leave him, you silly woman!” I would yell whenever I read or watched accounts of women being physically or verbally abused. But by not having the courage to break off my friendship with Tara, wasn’t I exactly the same as these women?

With the steam still coming out of my ears from the phone call, I recalled some of the other incidents where Tara had treated me disrespectfully. I had once lent her an outfit which I had never worn which she lost and she acted as though I had no right to question her as to its whereabouts. I never got it back and she never apologised for it. She even had the nerve to ask if she could borrow another outfit some time later. In our relationship she was the one who gave the advice; any advice I gave wasn’t well received as I wasn’t of the right social and intellectual calibre as far as she was concerned.

I had challenged her once when I caught her flirting with her close friend’s husband, who Tara had once described as “the love of her life”. Tara and this man had been so close for so many years that at one point it was thought they would get married. Tara's response to my query was to literally scream her defence of her behaviour at me in the street. I was nauseated by her attitude because I wasn’t accusing her of anything; I was simply telling her to be aware of what she was doing as her friend had looked very uncomfortable when the flirting took place. Later, instead of apologising for being completely out of line, Tara said very matter of factly that she had spoken to me that way she had because she could.

Despite all of these abuses I remained friendly with Tara through thick and thin. I was always there when she needed someone to talk to. Mine was one of the many shoulders that she cried on over the years when she despaired of ever getting married, which had been a dream of hers since she was a child. We hung out a lot and often spoke of life as single women. I wasn't bothered about being single but it bothered Tara a great deal. Tara's main gripe was that there were far more interesting things for people to do as a couple; people always invited you out to dinner and you fit into society better.

When Tara finally met her future husband on the internet, our relationship changed very quickly. Of course I knew it would change as it had to, but Tara pretty much cut me out of her life completely. I knew Tara well enough by that time to know what was really happening - having finally got her man, she could do what she had wanted to do for ten years...become part of the "couples set".

Still pondering the "out of sight, out of mind" comment, I started wondering who my real friends were. I began to evaluate all of the friendships I had at the time. I picked up my mobile phone and looked at each name in my contacts list, carefully assessing my relationship with each one. I deleted the ones who I believed I needed to separate myself from and at the end of that painful but necessary exercise, I could count the friends I had on one hand. It was a depressing but empowering moment. I vowed from that moment on that I would only befriend those who viewed me as their equal and who would love and respect me as much as I loved and respected them. If that meant that I would only have a handful of friends, so be it!!

With hindsight I can see that the toxic relationship with Tara was able to flourish because I allowed it to. I had issues with my self esteem at the time, but having dealt with that, no one could ever treat me that way now. I totally forgive Tara for everything and wish her all the best in her life. I've vowed not to be bitter about any of the unwholesome relationships that I have cut out of my life and this in itself is very healing and brings its own rewards.

Are any of your relationships toxic? If you answer in the negative to any of the following questions, you need to re-evaluate whether or not that person should be in your life:

1. Do you feel like an equal in the relationship? Does your friend like to give advice/suggestions to you more than they like to take it from you?
2. Do they drain you emotionally and spiritually?
3. Does your friend only contact you to hang out when they have nothing else to do? Do they only want to socialise with you for their own benefit?
4. Do they talk to you in a way that is disrespectful?
5. Do you tend to feel mostly good or bad after spending time in their company?
6. Are you afraid to challenge them when they do or say things that aren’t right? Why are you afraid?

Life is far too short to spend it with people who don’t deserve you. Walk away from every toxic relationship you have; if during the cull you discover that you only have one real friend, then thank God for them and treasure them, because believe me when I tell you, true friends are very rare jewels indeed!!

*Tara = not her real name