At the end of the General Hospital episode on Thursday, June 5, Denise Demuccio, Ava Jerome's double except for black hair and a voice straight out of Jersey Shore, copped to Silas that she is indeed Ava.  No surprise there.  We suspected it.

The big question on the minds of many viewers is, if she's Ava, why is her DNA different?

As always, I'm here to see you through the medical and legal matters that occur in stories on General Hospital.

 

We all know that a story plows through even if impossible things have to happen: Back from the dead, becoming pregnant the night of a miscarriage, lab data switched -- so Ava's DNA being changed shouldn't be a big deal if one plays fast and loose with the facts.

In this case, though, the change in DNA is based on scientific fact.  

First, let's look at what happens during a bone marrow transplant with accompanying chemotherapy or radiation.  

Chemo and radiation destroy the patient's cells. The doctor then takes bone marrow from a matched donor and transplants it through an intravenous method -- you know, like when you're in the hospital and on a saline drip. The method is called hematopoetic or blood-making cell transplantation.

Since there is blood in your bone marrow, the recipient of the bone marrow will take on the donor's DNA. This actually has been the cause of actual false identification in the past, as well as on the fictional General Hospital.

In the documented case, a man was accused of a sexual assault but was in prison at the time of the crime.

It was learned that he had a bone marrow transplant from his brother. His blood had his brother's DNA. However, the DNA from his cheek swab was different!  

Some fascinating DNA facts:

• If a man receives a bone marrow transplant from a woman, he can wind up with two X chromosomes, the chromosomal features of a woman. 
• One may also see his or her blood type changing.
• It is possible to have two different DNAs without a transplant. People born with two different DNAs are called chimeras.
• Your DNA can also change later in life. These people are called mosaics

?I read also that this DNA change that Ava is experiencing is temporary, but in fact, it is not.  It is temporary in blood transfusions.

Let's look at some interesting facts about "typing" DNA:

• DNA can be collected from hair, bone, skin tissue, saliva, semen, and blood.
• There are thirteen places on DNA that differ between individuals, and those thirteen places are what are used to produce DNA profiles. 
• The way the tests are carried out, an individual's DNA must be the same in every cell, but that isn't always true. 

Now, is this how it will be explained on General Hospital? Or did someone sneak into the PCPD lab and switch the resultsl?  They can rely on science here, not the de rigueur DNA swtich.

One important item: It is important that DNA is tested in both blood and in another tissue to make sure the DNA profiles match. 

Since we are dealing here with the Port Charles Police Department, this obviously was not done. Also the show cheated in one big respect: Normally a police department does a cheek swab, not a blood test.  I guess we can forgive that.