Saturday, January 9, 2010

DNA Fingerprinting Uses

What are some DNA fingerprinting uses? We’ve seen how DNA fingerprinting works, but what is it good for? There are a number of interesting examples of DNA fingerprinting uses. Alec Jeffreys invented DNA fingerprinting in 1985, and his method immediately was used to solve some serious issues. The first case that came to his attention was involving immigration. A family from Ghana had immigrated to the United Kingdom. When one of the four sons of the parents went for a visit to Ghana, he tried to come back and was detained at the airport by British immigration authorities, because his passport just wasn’t right. The authorities claimed that he wasn’t the son at all, but a cousin from Ghana who was trying to sneak into the country.

Jeffreys did DNA analysis of the mother and the three undisputed sons, as well as the son in dispute. The result was that he was definitely the son, and they allowed him to the country. Here we have an interesting DNA fingerprinting use, solving an immigration issue.

Criminal Cases

Soon, Jeffreys was called to a criminal case in Leicester. Two girls had been raped and murdered in the same area under similar circumstances two years apart. A man in jail confessed the second crime, but claimed innocence of the first one. Jeffreys did DNA fingerprinting of the victims, the suspect and semen that was found on the victims. As a result, Jeffreys concluded the same man had committed both crimes. It wasn’t the man who confessed, though. Why this guy confessed no one knows.

The police then asked all men in the area to give a blood sample. Five thousand men did so. When DNA analysis was done, there was still no match. Coincidentally, a woman overheard a man saying: “I gave two blood samples, one for me and one for a friend who didn’t want to give it”. The police found the man and asked him to give a sample. When they did the analysis, he turned out to be the killer.

DNA fingerprinting, as a result of this case, is now widely used in forensic cases.

Identifying People

Abhilasha Jeyarajah was a baby who was torn from his mother’s arms when, in 2004, a Tsunami hit Sri Lanka. Amazingly, Abhilasha survived. While his parents franticly looked for him, the baby was picked up by a local teacher and brought to the regional hospital. It was the worst day imaginable for the hospital staff. Hundreds of dead and dying children and adults were everywhere. When Abhilasha was brought in, the nurses were surprised to see that he was alive and healthy. It was a true miracle. He quickly became a celebrity in the hospital. Because he was the 81st infant brought in that day, they called him “baby 81”.

A few days later, his frantic parents came to the hospital, where they heard there were unclaimed babies. Joyfully, they were reunited with Abhilasha. “Not so fast”, said the hospital staff. In the previous two days, other couples had come to the hospital searching for their missing babies. Eight couples had claimed baby 81 was theirs. The question ended up with a judge.

There is a story in the Bible where King Solomon faced a dilemma of ruling which of two women was the true mother of an infant. Wise Solomon said: “I’m going to cut the infant in two so that each of you can have a half”. Of course the real mother was immediately revealed. In Sri Lanka, the judge had a worst case. He had nine couples claiming to be the parents of a six-month old boy.

Unlike Solomon, who just had wisdom, the judge had DNA for identification. Testing by molecular biologists soon found the real parents.

DNA in History

In 1918, with the Russian Communist Revolution raging; Czar Nicholas II, his wife and three of their children were killed in a town and buried in a shallow unmarked grave. In 1991, in a not Communist Russia, two amateur historians found what they thought was the grave of Nicholas II. There were two older people and three younger people. The sizes of the skeletons were consistent with the family. There were golden dental fillings. At that time not everyone in Russia could afford gold fillings.

The skeletons were too damaged for further identification, but fortunately, the bones had DNA. The short tandem repeats where compared in the bone with those of survivors of their family. There are surviving members of the Romanov family (the emperor’s family). For example, a great granddaughter of the Czar’s sister is still alive. The great grandson of the Czar’s aunt is still alive. Also, the body of the Czar’s brother was exhumed and some DNA was there.

The result: the same repeats were present in the dead family. That proved that they were from the Romanov family. There was a huge military funeral with full honors.

DNA fingerprinting has been used in many more instances. It was used to identify victims in the World Trade Center terrorist attacks in the United States in 2001. Many of the victims were beyond identification by any other means.

DNA databases are being built all around the world. For example, for some time in the United Kingdom, every one arrested for serious crimes has been DNA typed. There are now 3.5 million people in their database. In the United States there had been a number of propositions dealing with DNA typing for arrested people. The FBI has 3 million DNA stored and typed.

1 Comment:

deter migene said...

While a lot of DNA contains information for a certain function, there is some called junk DNA, which is currently used for human identification. At some special locations in the junk DNA, predictable inheritance patterns were found to be useful in determining biological relationships.

DNA Testing Immigration

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