Each individual has a unique DNA "fingerprint" based on the sequence of the A, T, G and C nucleotides in their genome. These differences allow scientists and criminologists to compare samples containing DNA (hair, blood, semen, stone age skeletons) with DNA from specific individuals. Beyond the obvious uses in criminology and paternity testing, this also is useful in reconstructing molecular genealogies and tracing the dispersion of specific Y-chromosome markers. For example, the Lemba tribe in southern Africa which had an oral history of Judaic descent was confirmed to have a much higher incidence of a Y-chromosome sequence that is found in the priestly lineage of Aaron than surrounding populations. Even though the Lemba tribe appears completely African, because of the father-son pattern of inheritance of the Y-chromosome it has remained present in their population unaltered for centuries. Other studies have suggested that Genghis Khan and his sons have ~16 million male descendants on the earth today and that ~8% of Irish men share the Ui Neill clan marker.
For me, the most striking contribution of DNA fingerprinting is its use in overturning wrongful convictions. For a real eye opener go visit the Innocence Project website. You can click on your state and read about every case of wrongful conviction overturned by DNA evidence (251 post-conviction exonerations to date nationwide). You can also see if your state offers any compensation for wrongful conviction (mine doesn't) or even requires samples that contain DNA evidence to be saved for future reference (mine doesn't). The unavoidable conclusion of all this is that the death penalty has will probably continue to result in the execution of innocent individuals.
Thursday, March 11, 2010
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Yes, it's a major problem. The Innocence Project does good work--I applied to work for them right after law school, but they don't have the funding to hire very often. In light of this disturbing evidence, the death penalty should be reconsidered.
ReplyDeleteThere's something we can agree on Sparkle. (And wouldn't that have been a cool place to work?!) My dad always maintained that it cost more to execute a prisoner than hold them for life. I've never fact checked him on this so I don't know it it's true.
ReplyDeleteIn terms of the justice system, I think most people would agree that a false positive (wrongful conviction, type I error for the stats types right?) is worse than a false negative (gets away with it, type II error) in the justice system. I've always thought it was impossible to reduce type I errors without increasing type II's but maybe DNA evidence can reduce both of them. At any rate, if you got rid of the death penalty you would be sure that you weren't executing an innocent, just consigning them to life in prison.
"In terms of the justice system, I think most people would agree that a false positive (wrongful conviction, type I error for the stats types right?) is worse than a false negative (gets away with it, type II error)"
ReplyDeleteIn the immortal words of Clancy Wiggum:
"I'd rather let a thousand guilty men go free than chase after them."
Rob, it seems like dad was right on the costs of the death penalty: http://lubbockonline.com/stories/121309/loc_535156806.shtml
ReplyDeleteThis is because of the high legal costs for death penalty cases, not because executions are costly. Although there is some satisfaction with giving some fool the chair, I would agree that the sensible thing for now is to discontinue the death penalty because of the wrongful convictions and no evidence of deterrence to crime.