Capital Defense Weekly

Problems with DNA?

The Los Angeles Times notes DNA database “hits” are coming under fire.  While DNA can exclude a person from being a source, it appears possible that the probability odds for “inclusion” are widely overrated. [more]

State crime lab analyst Kathryn Troyer was running tests on Arizona’s DNA database when she stumbled across two felons with remarkably similar genetic profiles.

The men matched at nine of the 13 locations on chromosomes, or loci, commonly used to distinguish people.

The FBI estimated the odds of unrelated people sharing those genetic markers to be as remote as 1 in 113 billion. But the mug shots of the two felons suggested that they were not related: One was black, the other white.

In the years after her 2001 discovery, Troyer found dozens of similar matches — each seeming to defy impossible odds.

As word spread, these findings by a little-known lab worker raised questions about the accuracy of the FBI’s DNA statistics and ignited a legal fight over whether the nation’s genetic databases ought to be opened to wider scrutiny.

In Maryland, the article reports:

A similar fight occurred in a death penalty case in Maryland during the summer and fall of 2006.

The prosecutor saw a DNA match between a baseball cap dropped at the crime scene and the suspect as so definitive that he didn’t plan to tell the jury about the chance of a coincidental match, records show.

Seeking to cast doubt on the evidence, the defense persuaded the judge to order an “Arizona search” of the Maryland database. The state did not comply.

After the defense filed a contempt-of-court motion, Michelle Groves, the state’s DNA administrator, argued in court and in an affidavit that, based on conversations with Callaghan at the FBI, she believed the request was burdensome and possibly illegal.

According to Groves, Callaghan had told her that complying with the court order could lead Maryland to be disconnected from CODIS — a result Groves’ lawyer said would be “catastrophic.”

Groves’ affidavit was edited by FBI officials and the technology contractor that designed CODIS, court records show. Before submitting the affidavit, Groves wrote the group an e-mail saying, “Let’s see if this will work,” court records show.

It didn’t. After the judge, Steven Platt, rejected her arguments, Groves returned to court, saying the search was too risky. FBI officials had now warned her that it could corrupt the entire state database, something they would not help fix, she told the court.

Platt reaffirmed his earlier order, decrying Callaghan’s “unilateral” decision to block the search.

“The court will not accept the notion that the extent of a person’s due process rights hinges solely on whether some employee of the FBI chooses to authorize the use of the [database] software,” Platt wrote.

The search went ahead in January 2007. The system did not go down, nor was Maryland expelled from the national database system.

In a database of fewer than 30,000 profiles, 32 pairs matched at nine or more loci. Three of those pairs were “perfect” matches, identical at 13 out of 13 loci.

Experts say they most likely are duplicates or belong to identical twins or brothers. It’s also possible that one of the matches is between unrelated people — defying odds as remote as 1 in 1 quadrillion.

Maryland officials never did the research to find out.

[h/t Saor -- I should note that on a lark I recently did a version of DNA testing, albeit confined to non-junk section of the Y-chromosome.  I was a 12 point genetic match for 40+ other people in one database (about 100th the CODIS database side) and 25+ people in another. Only one hit was with a a relative, albeit a very distant one. All the others were other people, generally of northwestern European (esp. England, Ireland & Scotland). One of the matches, oddly enough, was another lawyer, a partner at Akin Gump.]

h