A recent metagenomic study analyzed the microorganisms...

A recent metagenomic study analyzed the microorganisms present on surfaces within the entire subway system of New York City. The researchers found hundreds of bacterial species in the subway, most of them nonpathogenic. Interestingly, almost half of all DNA found in the subway matches no known organism. a. The scientists found that different subway stations had characteristic microbiomes. How might this observation be useful to the police? b. Because the majority of the subway DNA that could be identified was bacterial, the researchers presume that most of the DNA fragments that could not be matched to a known organism are bacterial. Why do you think that so many bacterial species are unknown to us? What feature of these unknown bacteria might prevent us from studying them?

A recent metagenomic study analyzed the microorganisms present on surfaces within the entire subway system of New York City. The researchers found hundreds of bacterial species in the subway, most of them nonpathogenic. Interestingly, almost half of all DNA found in the subway matches no known organism.
a. The scientists found that different subway stations had characteristic microbiomes. How might this observation be useful to the police?
b. Because the majority of the subway DNA that could be identified was bacterial, the researchers presume that most of the DNA fragments that could not be matched to a known organism are bacterial. Why do you think that so many bacterial species are unknown to us? What feature of these unknown bacteria might prevent us from studying them?

Key Concepts

Forensic Microbial Fingerprinting

Forensic microbial fingerprinting is the concept of using distinctive microbial communities as biological markers to aid in tracking or identifying the sources of samples. The characteristic and stable nature of microbiomes in specific locations, such as different subway stations, can provide clues in criminal investigations by linking a person or object to a particular environment.

Culture-Independent Methods and the Unknown Microbial Diversity

Many bacterial species remain unknown due to the limitations of traditional culture-based methods. Culture-independent methods, such as DNA sequencing used in metagenomic studies, have revealed that a large fraction of environmental DNA corresponds to bacteria that either cannot be readily cultured in the laboratory or require specific conditions to grow. This highlights a vast, uncharacterized microbial diversity and presents a challenge for studying these organisms in detail.

Microbiomes

Microbiomes refer to the communities of microorganisms living in a specific environment. In the context of the subway system, different stations exhibiting characteristic microbiomes can serve as unique biological markers, potentially useful in forensic investigations for determining the origin or movement of individuals based on the microbial signatures they carry.

Metagenomics

Metagenomics is the study of genetic material recovered directly from environmental samples, allowing researchers to analyze complex communities of microorganisms without the need to culture them. This approach can reveal both the diversity of known organisms and the presence of unknown genetic material in a given environment.

Transcript

00:01 Okay, so this question is kind of cool, actually, to think about.

00:04 So a recent metagenomics study analyzed the microbes present in the surfaces of within the entire subway system of new york city.

00:12 And researchers found that hundreds of bacterial species in the subway, most of which are non -pathogenic, meaning they don't cause disease.

00:20 They found that almost half of all the dna found in the subway matches no known organism, meaning that it belongs to a bacteria.

00:30 Is just something that we have never seen before because they don't grow anywhere else or rather it's just never been looked at before until now.

00:41 So a, the scientists found that different subway stations have characteristic microbiomes.

00:46 How might this observation be useful to the police? well, they can match an unknown bacterial sample to the specific subway station with this bacteria.

01:25 So essentially, they can be used to find, for lack of a better term, the scene of the crime.

01:41 So you can use it to associate a particular piece of evidence to a location.

01:54 Okay, b, because the majority of the subway dna that could be identified was bacterial, the researchers presume that most of the dna fragments that could not be matched to a known organism are bacterial.

02:07 Why do you think that so many bacterial species are unknown to us? what features of these unknown bacteria might prevent us from studying them? they can be unknown to us for a lot of different reasons.

02:19 One, just have not looked for them.

02:26 That's one reason.

02:29 For example, i mean, this whole thing in general, why would you ever swab a subway station, right? you do it and it's been done just to see.

02:38 But like, is there actually a reason to look for bacteria in a subway station? there really wasn't.

02:43 So if you think of rationally designed experiments, it makes no sense to spend your time on them because what are you actually learning from it.

02:50 No one really put much stock into it, so that's why they never went looking...

Please give Ace some feedback