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{♫Intro♫}
When you think about it, modern forensic science is pretty amazing.
It allows crime scene investigators to take the tiniest trace evidence, like a hair or
a fingerprint,
and use it to find criminals.
But as powerful as today’s technologies are, everything can benefit from an upgrade.
And researchers have been working on new ways to help medical and legal investigators and
their forensic teams
track down suspects, analyze evidence, and even peer inside remains without picking up
a scalpel.
There are still kinks to be worked out, of course, but today we’re going to talk about
six updates to forensic techniques that investigators might be using in the near future.
Fingerprints have been used as a way to ID people for a long time.
The first known example comes from a Chinese CSI book from three hundred BCE,
though it took awhile for other people to catch up.
But one of the conundrums with fingerprints is that while we can use them to tell if someone
has touched an object,
we don’t know when that contact occurred.
It could have been during the crime, but it also could have been before or after.
But in 2018, scientists in the Netherlands reported that
they had created a kind of “map” of the biological constituents of fingerprints which
could help figure that out.
You see, fingerprint marks are made up of oils, proteins, and other skin secretions,
which help transfer the ridge pattern of your fingers to the objects you touch.
And because these components change as they age, looking at them could
tell investigators how old the prints are.
Other groups have also been busy mining the biological components of fingerprints.
Multiple studies in the last ten years have shown it's possible to use fingerprints
to tell if someone has been smoking, using certain drugs, or all kinds of other information,
including what they eat and their general hygiene habits.
That’s helpful because many prints don’t have matches in police databases.
So those kinds of details could help investigators narrow down the suspect pool.
And it may mean that, someday, even the most smudgy, incomplete prints could still be used
to help ID suspects.
DNA tests are a much newer tool—they’ve only existed since the 1980s.
And at first, there was kind of a big downside to them: the analysis process was slow.
It used to take days to get sequences.
You see, it’s hard to read a single molecule of DNA,
so most sequencing methods require making a lot of copies first.
But over the last decade, the process has gotten much faster.
And in two thousand nineteen, researchers announced they’d found a way
to skip the copying step altogether, by using a chip loaded with CRISPR and graphene instead.
The CRISPR molecules are designed to bind to certain DNA sequences
while the electrically-sensitive layer of graphene can tell if the CRISPR molecules’
have been turned on,
so to speak, by finding the right DNA sequence.
It can then transmit this signal to a computer chip
So scientists might be able to get DNA sequences in minutes.
What might help forensics more, though, is not just faster DNA processing, but a better
understanding of our genes.
Right now, we can make some predictions about how a person looks based on their genes,
but they’re pretty hit-or-miss.
We can’t even reliably predict whether a person naturally has blue eyes or brown ones.
But, if we understood our genomes better, some researchers think DNA testing
could essentially be used like a police sketch artist to help narrow down the suspect pool.
And, better tools could also help us use degraded samples or untangle samples that are a mix
of multiple people.
For all the power DNA testing has, a DNA sample isn’t always easy to obtain.
for example, If you want to get the DNA needed for most ID methods from a hair sample,
you have to have the hair’s root—the part where new hair actually grows from.
No root, and you’re largely out of luck.
But in the future, we might be able to simply ID any hair thanks to non-human DNA.
That’s because microbes are everywhere.
They live on our skin, in our mouths and stomachs, and on our hair, forming what’s known as
our microbiome.
And it turns out our microbiomes aren’t all the same.
One study back in 2014, for instance, found differences between the microbes
living on different people’s hairs—even when those people lived together.
And researchers have been able to use microbes to tell who owns a particular cell phone or
keyboard,
or where someone had been from the organisms on their shoes.
Examining microbiomes might also reveal other things about a person’s lifestyle,
like their diet, or medicines they take, which could narrow the suspect pool.
That said, our microbiome isn’t constant—it can change over time.
And that means it’ll probably never replace traditional DNA profiling, but it could help
augment it.
There are lots of cases where trained canine units can help sniff things out.
But in the future, investigators might upgrade their furry friends with electronic noses.
We’re seeing an explosion of different “e-noses”, many of which involve some really cool, funky
engineering —
like, detectors that use vibrating quartz crystals, or spongy mixes of metal and carbon,
or ones that incorporate carbon nanotubes.
One model from Stanford actually uses fluorescent DNA to detect different chemicals.
They stuck fluorescent compounds onto outstretched “whiskers” made up of single-stranded
DNA molecules so that they change color when they bind to certain substances.
This, along with some of the other e-noses, are especially cool because they can combine
the identities of many different chemicals to figure out what’s really being smelled—like
our brains do.
And many real-world scents aren't just a single chemical.
The “smell” of bread, for instance, can be made up of hundreds of different chemicals.
Since we can train animals to sniff out all kinds of things, if these human-made noses
can
become as powerful as living ones, then they could help close all sorts of cases.
But what if you need to test biological samples?
Like, if you’re wondering
if a bit of blood came from a human or an animal, even if the DNA itself is too degraded
to tell.
Spectroscopy can sometimes help with that, but we’re starting to use microRNAs as well.
MicroRNAs are very small bits of genetic material, maybe only about eighteen to twenty-four bases
long.
Despite being made of genetic stuff, they don’t actually code for anything.
Instead, they help regulate some cellular processes, like gene expression.
And they’re found in all kinds of living organisms, so they could be used to tell whether
a particular stain came from a person or something else.
What’s interesting about them is that they’re found in just about all of the cells in our
body,
but how much of them—how they’re expressed—is specific to different types of tissue.
So by reading the microRNA in a sample, scientists might someday have a way
to tell confusing biological samples apart.
Or figure out that a particular stain is a mix of two things.
Also, because they’re so, so small, they’re less prone to breaking down and degrading
over time—
at least theoretically.
In one paper from 2010, a blood sample that’d been in a lab for a year was still able to
be used for identification.
We’re still working on identifying the right markers and validating them, though, so they’re
not super useful yet.
Sometimes crime dramas seem pretty realistic.
Other times, they go all out on the CGI, pulling up big, holographic 3D images.
The thing is, those might not be as unrealistic as you might think,
because scientists are working on what’s known as virtopsies—because, I guess,
“virtual autopsies” was just too long or something.
These are basically the kind of medical scans we do now for living humans,
like CT scans or MRI scans, but done by a medical specialist on a cadaver instead.
These are neat because they can help us visualize things you can’t easily see with traditional
methods.
Back in two thousand three, for instance,
researchers used an MRI to do a virtual autopsy on a victim of a fatal scuba diving accident.
The MRI was able to find evidence of gas embolisms—basically, bubbles of air—
in areas of the body that were inaccessible to a standard autopsy, like the spine or in
tiny blood vessels in the brain.
Also, these scans could function as a kind of back-up.
Traditional autopsies rely on expert analysis and recorded dictation –– essentially,
the specialist narrating what they’re seeing.
But if the expert misses or misinterprets something,
it can be impossible to go back and check again.
Say, for example, an expert misses some sort of organ damage or a tiny blood clot.
In a year, that body will be buried or cremated, but a scanned image will still be around.
And because you don’t actually have to cut into a body to do a virtual autopsy,
there’s less chance of accidentally destroying evidence.
Furthermore, scans are preserved basically forever,
so we could go back and review the evidence again weeks, or even years into the future.
Of course, a lot of this is still in the research phase—
making these available to investigators on a daily basis will require some work.
And getting them to the point where we’re able to use them in the legal systeml might
be tricky.
Those super-fast DNA tests, for instance, are currently running into questions about
validation and reliability.
And if these new forensic technologies are going to be used widely,
we’ll also need to make sure they’re affordable and practical.
But if we can do that, advances like these could one day help us catch criminals, find
contraband,
and solve cold cases faster and more accurately than ever.
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{♫Outro♫}