Does anyone know of any good articles or have any good information on DNA from fingernail scrapings? I have an agg. sexual assault of a child case (digital penetration) in which the cops got fingernail scrapings from the defendant 12 days after the offense. No one expected to find the victim's DNA under his nails, they just did it as an interview technique. Of course, none of the victim's DNA was found. The defense has hired Bill Watson from Orchid Cellmark to come testify that it would be possible to find the victim's DNA under the defendant's nails for some period later, however, they have slipped and mentioned a study that says the DNA might be there 7-8 days later, and they're probably stretching it to get him to say 12 days later. I want to either keep the expert out totally or really cross the heck out of him. Any advice?

Call Judy Floyd at Genescreen. She is the best I know.

Greg is right about Judy. She is the best DNA expert I have ever used. However, if I recall correctly, Orchid Cellmark and Genescreen joined several years back. So, I believe that she and Bill Watson may work for the same company. That might pose a problem.

Sammy's right, Orchid and Cellmark are all in the same shop now.
I just finished a murder case in which Orchid Cellmark found the defendant's DNA under the victim's fingernails. The analyst I worked with never gave me any indication that I should be at all concerned about the idea that the DNA could be hanging around under the nails for very long at all, certainly not almost 2 weeks.

I have 2 go-to people for all my DNA questions - Clay Strange who used to be w/ the Travis Co. DA's office (yes, he's gone to the dark side but not where DNA is concerned) and Meghan Clement - she's the head of the LabCorp DNA lab up in North Carolina (I don't have her # handy but I'm sure it's on the internet). She's done casework for me multiple times and has given me a ton of advise over the years.

Lisa -- I don't have any reason to think that DNA couldn't hang around under a dead person's nails forever, it's whether it can hang around under a live defendant's nails for 10-12 days, given normal daily activities, washing, etc. That's my area if inquiry. And my trial is Monday, so I can't go get a new expert. I have the head of the DPS lab if I need him, I was just seeing if anyone knew of any studies or strategies. Thanks.

Seems to me that a jury would be able to grasp that normal daily activity would diminish the chances of finding DNA. Not to mention the fact that a defendant who did THAT would probably wash his hands afterwards at least a few times.....
My victim had been around the defendant a week or two before her death, then also on the night she died. Orchid seemed awfully comfortable w/ the idea that since the DNA was under the fingernails, it would've had to have come from that last encounter, not some previous one.
You may want to give Meghan a shout - if there are any good studies out there, I'd bet she knows of them.

I'm totally sold on the commom sense idea that, duh, no one would still have that under his nails after 12 days (not to mention that with a prepubescent girl, how much fluid would there be?), I'm just always looking for ways to either keep an expert off or gut them. Thanks.