sexta-feira, 1 de junho de 2012

Quanto vale uma prova de DNA?

Proposta cria banco de DNA para investigação de crimes violentos

A Câmara analisa projeto que regulamenta a criação de um banco nacional de DNA para auxiliar nas investigações de crimes violentos. A medida está prevista no Projeto de Lei 2458/11, já aprovado pelo Senado. Conforme a proposta, o material desse banco será gerenciado por uma unidade oficial de perícia criminal e será sigiloso.
O autor da proposta, senador Ciro Nogueira (PP-PI), explica que o projeto apenas formaliza a instituição de um banco de material genético que já vem sendo testado no Brasil. O sistema, denominado Combined DNA Index System (Codis), é o mesmo empregado nos Estados Unidos e em outros 30 países, segundo Nogueira.
O objetivo da proposta é estabelecer uma unidade central gerenciadora de vestígios genéticos deixados em locais de crimes, como sangue, sêmen, unhas, fios de cabelo ou pele. Também constará do banco o material genético de criminosos condenados por violência dolosa, ou seja, intencional.

“Atualmente os resultados da determinação de identificação genética pelo DNA já são rotineiramente aceitos em processos judiciais em todo o mundo. Obviamente, o DNA não pode por si só provar a culpabilidade criminal de uma pessoa ou inocentá-la, mas pode estabelecer uma conexão irrefutável entre a pessoa e a cena do crime”, ressaltou o senador.

SigiloPela proposta, os dados do banco de DNA serão sigilosos e as pessoas que os utilizarem para qualquer fim diferente daquele determinado pela Justiça responderão civil, penal e administrativamente.
Além disso, os perfis genéticos deverão seguir normas constitucionais e internacionais de direitos humanos. Ou seja, não poderão revelar traços somáticos ou comportamentais – apenas o gênero do investigado ou do condenado.

Tramitação
A proposta, que tramita em regime de prioridade, será analisada pela Comissão de Constituição e Justiça e de Cidadania antes de seguir para o Plenário.


OBS: PASSOU e FOI SANCIONADO em 29 de maio de 2012.


POR OUTRO LADO....


DNA Evidence Can Be Fabricated, Scientists Show

Published: August 17, 2009

Scientists in Israel have demonstrated that it is possible to fabricate DNA evidence, undermining the credibility of what has been considered the gold standard of proof in criminal cases.

The scientists fabricated blood and saliva samples containing DNA from a person other than the donor of the blood and saliva. They also showed that if they had access to a DNA profile in a database, they could construct a sample of DNA to match that profile without obtaining any tissue from that person.
“You can just engineer a crime scene,” said Dan Frumkin, lead author of the paper, which has been published online by the journal Forensic Science International: Genetics. “Any biology undergraduate could perform this.”
Dr. Frumkin is a founder of Nucleix, a company based in Tel Aviv that has developed a test to distinguish real DNA samples from fake ones that it hopes to sell to forensics laboratories.
The planting of fabricated DNA evidence at a crime scene is only one implication of the findings. A potential invasion of personal privacy is another.
Using some of the same techniques, it may be possible to scavenge anyone’s DNA from a discarded drinking cup or cigarette butt and turn it into a saliva sample that could be submitted to a genetic testing company that measures ancestry or the risk of getting various diseases. Celebrities might have to fear “genetic paparazzi,” said Gail H. Javitt of the Genetics and Public Policy Center at Johns Hopkins University.
Tania Simoncelli, science adviser to the American Civil Liberties Union, said the findings were worrisome.
“DNA is a lot easier to plant at a crime scene than fingerprints,” she said. “We’re creating a criminal justice system that is increasingly relying on this technology.”
John M. Butler, leader of the human identity testing project at the National Institute of Standards and Technology, said he was “impressed at how well they were able to fabricate the fake DNA profiles.” However, he added, “I think your average criminal wouldn’t be able to do something like that.”
The scientists fabricated DNA samples two ways. One required a real, if tiny, DNA sample, perhaps from a strand of hair or drinking cup. They amplified the tiny sample into a large quantity of DNA using a standard technique called whole genome amplification.
Of course, a drinking cup or piece of hair might itself be left at a crime scene to frame someone, but blood or saliva may be more believable.
The authors of the paper took blood from a woman and centrifuged it to remove the white cells, which contain DNA. To the remaining red cells they added DNA that had been amplified from a man’s hair.
Since red cells do not contain DNA, all of the genetic material in the blood sample was from the man. The authors sent it to a leading American forensics laboratory, which analyzed it as if it were a normal sample of a man’s blood.
The other technique relied on DNA profiles, stored in law enforcement databases as a series of numbers and letters corresponding to variations at 13 spots in a person’s genome.
From a pooled sample of many people’s DNA, the scientists cloned tiny DNA snippets representing the common variants at each spot, creating a library of such snippets. To prepare a DNA sample matching any profile, they just mixed the proper snippets together. They said that a library of 425 different DNA snippets would be enough to cover every conceivable profile.
Nucleix’s test to tell if a sample has been fabricated relies on the fact that amplified DNA — which would be used in either deception — is not methylated, meaning it lacks certain molecules that are attached to the DNA at specific points, usually to inactivate genes.


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