Week 4 - 8 Early Uses of DNA Profiling

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Del curso dictado por Nanyang Technological University, Singapore

Introduction to Forensic Science

359 calificaciones

Nanyang Technological University, Singapore

Introduction to Forensic Science

359 calificaciones

We have all seen forensic scientists in TV shows, but how do they really work? What is the science behind their work? The course aims to explain the scientific principles and techniques behind the work of forensic scientists and will be illustrated with numerous case studies from Singapore and around the world. Some questions which we will attempt to address include: How did forensics come about? What is the role of forensics in police work? Can these methods be used in non-criminal areas? Blood. What is it? How can traces of blood be found and used in evidence? Is DNA chemistry really so powerful? What happens (biologically and chemically) if someone tries to poison me? What happens if I try to poison myself? How can we tell how long someone has been dead? What if they have been dead for a really long time? Can a little piece of a carpet fluff, or a single hair, convict someone? Was Emperor Napoleon murdered by the perfidious British, or killed by his wallpaper? *For Nanyang Technological University (NTU) students, please be noted that this course will no longer be eligible for credit transfer.

De la lección

DNA in Forensics

Opinion Poll 30:00

Week 4 - 1 Introduction to DNA16:15

Week 4 - 2 Techniques used in DNA Profiling8:16

Week 4 - 3 Polymerase Chain Reaction (PCR)4:29

Week 4 - 4 Short Tandem Repeats (STR)12:05

Week 4 - 5 Colin Pitchfork Case5:37

Week 4 - 6 Cold Cases I4:22

Week 4 - 7 Cold Cases II3:20

Week 4 - 8 Early Uses of DNA Profiling6:03

Week 4 - 9 Mitochondrial DNA9:19

Week 4 - 10 DNA Profiling of Other Species2:46

Week 4 - 11 Peter Falconio & Joanne Lees Case; Summary6:48

Conoce a los instructores

Roderick Bates
Associate Professor
Division of Chemistry & Biological Chemistry | School of Physical & Mathematical Sciences

[MUSIC]

So the first cases using DNA profile come from the United Kingdom,

and the technique then spread worldwide, including to the United States.

One early use of DNA technology in the

United States was the case of Kirk Bloodsworth.

And he lived in Baltimore County, Maryland,

and in 1985, he was found guilty of the rape-murder

of a nine year old girl called Dawn Hamilton.

In 1986, the following year, because of

a legal technicality, his conviction was quashed. But

he was not freed, because he was re-tried, found guilty once again, and that guilty

verdict was confirmed when he appealed. But he insisted throughout, he was not guilty.

After several years in prison,

his lawyers finally forced the state to do DNA tests

of the semen that was found in the little girl's underwear,

and that DNA did not match Kirk Bloodsworth,

so he was released and given back his freedom.

Some years later, the DNA from that underwear was compared to DNA in the U.S.

national databank and it matched a known criminal named Kimberly Shay Ruffner.

Now the irony is

that while Kirk Bloodsworth was in prison for the murder he did not commit,

Kimberly Shay Ruffner had actually been in the same prison for a different offense.

How far back can we go?

Well, we can go a very long way back.

One of the people who spent longest in

prison for a crime he didn't commit, but was

then released due to DNA evidence, was a man

called James Bain from Florida in the United States.

He was found guilty of rape in 1974,

partly based on the testimony of an eyewitness.

And it took until 2009 for the truth to be

established, and that's when he was released because of DNA evidence.

Under Florida Law, he was compensated at the

rate of $50,000 for each year in prison.

As he'd been in prison for 35 years, that's 1.7 million U.S. dollars,

but no amount of money can compensate you for the loss of 35 years of freedom.

So what happens if the DNA found at the

crime scene doesn't match anybody in the national database?

Well, then you may have to identify a suspect through other

means, or maybe you can find something in the DNA that

will help you.

In 1988, a prostitute called Lynette White was found stabbed to death.

Three men were convicted for this crime,

but on appeal, their conviction was crushed, and this meant

the police had to go back and re-investigate the crime.

Well, this takes a lot of time and the

crime scene was only re-investigated in the year 2000.

That's

a long time later,

and the room in which she had been murdered had, of course, been repainted.

It had been redecorated,

which I think is a reasonable thing to do if there was a murder in it.

And what they had to do was to peel back the

layers of new paint back to the layer of paint that was on the surface

back in 1988. And they were able to find bloodstains

which had been preserved under the paint, and extract DNA from those bloodstains.

But when that DNA was put into the national database, there were no matches.

Or at least, there were no perfect matches, meaning that the

person whose blood that was, was not represented in the database.

But inspection of the DNA showed, quote, "an unusual feature".

And when the DNA database was analyzed for this particular

feature of the DNA, there were 600 people who shared it.

From those 600, 70 were short-listed for one reason or another, and from those 70,

one of them stood out particularly,

and he was a teenager with motoring offence.

But he hadn't been born at the time of the murder,

and of course, his DNA was not a perfect match, so it couldn't have been him.

Turned out to be his uncle,

a man called Jeffrey Gafoor.

[BLANK_AUDIO]

So Jeffrey Gafoor was convicted of the murder, based upon

this unusual feature which he shared with his relative,

who was in the database.

[BLANK_AUDIO]

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