Name: 【TEDx】Forensic DNA Mixups | Greg Hampikian | TEDxBoise
Uploaded: 2016-03-20T06:03:04.000Z
Duration: 18 min 42 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Today I'm going to talk about some serious stuff,

Adverbs of manner

and then hopefully, we'll have a little bit of humor along with it.

I'm going to need some help from some people in the front row to commit a crime.

And for the serious part, I'm going to be talking about DNA errors,

- and I'm only going to ask you to imagine this briefly -

a loved one is hurt or killed in a crime.

Someone's finally arrested, you go through the endless trials,

and someone is incarcerated for the crime.

Twelve years, 20 years later, you hear they got the wrong person.

That's the kind of thing that we are trying to avoid.

we have to constantly be looking at our techniques

So I'm going to talk about some issues in my own field that I've seen in my work.

I have cases overseas: Asia, Africa, Europe.

And some of the things I've seen that I'm concerned about,

that I have raised at professional meetings,

some of it has never been shown before, and I'll show you tonight.

So we're talking about forensic DNA errors.

I don't want to you to think it's all bad,

it's not all bad, it's a great field, it's my life.

And I'm going to break it into two categories:

one is statistical and interpretative errors,

so things where the conclusions are wrong, based on human reasoning and mathematics,

and the other one is contamination, which is kind of easy to understand.

Somebody spills some DNA while it gets transferred,

and then I'll tell you what my lab here in Boise is working on

So we'll have a first slide, I'm going to turn you into the DNA experts.

This is the easy stuff, this is a single source,

I can teach you guys to do this immediately.

Let's say I decide I'm going to commit a crime with this.

It's clean, it just got out of the dishwasher,

and there was bleach in the dishwasher, so it has no DNA on it.

I touch it, and I go to the front row, and I commit a murder.

they collect some of the blood to identify the victim,

They take a swab, they swab it, and what's really nifty about these swabs

is you can just knock the ends off of them,

but I'm going to pull it, and put it in here.

you get it from your mother and your father.

So that means that every location on the DNA that I'm going to look at

- and I've shown you these are four locations here, in the columns;

at every location you've got one number from mom, one number from dad.

I've got one number from my mom, one from dad, I'm the suspect.

Greg Hampikian: My students, when I say the word 'match',

maybe one in 10,000 people would be included in this match,

Alright, that's a single source, everybody gets it right.

Before I commit the crime, a couple of other people I offered--

So now, they come in, and they do the swab, and they get a mixture.

This is what they get: these again are four locations of DNA,

but now, there is a bunch of what we call alleles or sizes in there.

The question becomes, "Am I included in that?"

So, am I still included, or are all of my sizes in there?

GH: The statistics is now something like one in 10 or maybe one in 50.

And that's because more people could potentially be included.

Now, you think that this would be an easy concept,

we'd have mathematics that can deal with it,

but when laboratories are given the same data,

they'd sometimes vary in that statistic over ten to the 10.

That's the difference between going to court and say,

"There was 30 dollars of damage to my car,"

than the combined gross domestic product of every country

So the statistics are done differently in different labs,

and they give a very different impression based on how the statistics worked before.

Subtitles ListPlay Video

【TEDx】Forensic DNA Mixups | Greg Hampikian | TEDxBoise

audience

case

crime

statistic