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What makes the smell of a human corpse unique to hounds

After the flames from California’s forest fires died down, authorities brought in cadaver dogs to sniff through the charred remains of homes, woodland and the animals that perished in the fires, in their search for human victims. But how exactly can a hound discern between the smell of a deer carcass and that of a human remains? Researchers asked themselves the same question, and the results of their work reveal exactly how: Decomposing human bodies release a unique chemical cocktail, and experts hope the breakthrough can be useful to improve cadaver dog training or leaqd to the developmen of machines that could allow them to sniff out bodies faster than ever before.

Image via cliparsheep Image via cliparsheep

“The smell of death” has been puzzling researchers for more than a decade. Two papers sparked the scientific community’s efforts in 2004 — one from a research station in Tennessee titled “Body farm” that analyzed the gases released during the latter stages of decomposition, the other from Greece, that focused on the early stages of the macabre process.

The preliminary list of carbon-based compounds given off during decay that these papers put together has been added on extensively since then. However, there have been conflicting reports about which ones are emitted only by humans. And so, in 2010 the Belgian Disaster Victim Identification Team asked analytical chemist Eva Cuypers and her forensic toxicology lab at the University of Leuven in Belgium for to find the best way to train cadaver dogs to pick out human scents.

Cuypers’s graduate student Elien Rosier started by putting tissue samples and organs from six autopsied corpses in jars in a lab closet. The jars were closed using screw caps which let in some air. They had stoppered holes that allowed the team to periodically take samples of the gas build-up inside.

Other jars were set up with pig, mouse, mole, rabbit, turtle, frog, sturgeon and bird remains. Pig remains in particular have often been used in past decomposition studies because of their rare similarity to human bodies: They have the same microbes in their guts, the same percentage of body fat, and similar hair as people. But it was not clear whether the decomposition process was the same because the two species had never been studied under identical conditions.

Rosier sampled the gases released by all the jars, and compared them by species. It took a long 6 months of work, during which she identified 452 compounds that make up the rotting smell of cadavers. Her first try was with compounds containing sulfur, as they seemed to differentiate between the samples. They weren’t unique to humans however, or even present in all humans — and they weren’t very stable chemically, disappearing over time; so she looked to .

Esters are chemical compounds that are crucial in the formation of animal fats. She found that eight compounds distinguished pig and human remains from those of other animals, and five esters separated pigs from humans, PLOS ONE reports:

“The mixture of [these] compounds might be used in the future to more specifically train cadaver dogs,” Cuypers says.

“So far there [hasn’t been] any study based on monitoring human and pig carcasses under exactly the same conditions,” says Agapios Agapiou, an analytical chemist at the University of Cyprus in Nicosia who was not involved with the work. “But there are still many steps before creating a synthetic substance to train cadaver dogs.”

John Sagebiel, an analytical chemist at the University of Nevada, Reno, who was also uninvolved in the study. says relying solely on analytical chemistry to determine what cadaver dogs are sniffing out is too limited. It would be better to work with the dogs themselves to figure that out, he adds.

“I don’t think there’s one specific thing that says it’s human,” he says.

Arpad Vass — who is associated with the University of Tennessee, Knoxville, Body Farm and has compiled a list of compounds released by decomposing humans — points out that the use of specific tissues, as opposed to a whole body, and their isolation in jars means the researchers are looking at just a subset of the bacteria and other environmental factors that influence decomposition.

Cuypers says her team plans to address some of these shortfalls in future studies.

“The next step in our research is to see whether the same compounds are found in buried, full decomposing bodies in the field and to see whether dogs trained on the mixture respond more specific[ally] to human decomposing bodies.” If this cocktail passes muster, the find could pave the way for developing an electronic nose that can do what dogs do, she adds.

Pathological Gamblers Exhibit Characteristics of Drug Addicts

Pathological gambling is a condition where a person has an irresistible urge to gamble which leads into a condition of problem gambling. Often, a pathological gambler will engage in criminal activity in order to feed their live or habit and in this article we will talk about some of the behaviors and characteristics of problem gamblers.

First, let’s look at the behavioral characteristics of problem gamblers. For many, the symptoms of problem gambling will mimic drug addiction and some problem gamblers are mistaken as drug addicts. Among these behavior characteristics include preoccupation and loss of control in connection with their gambling. They have usually made many attempts to stop their activity but were unable. Problem gamblers are often preoccupied with gambling, gambling strategies, or even ways to raise capital to gamble with.

Other behavioral characteristics include withdrawal, lying, and even tolerance to gambling.  A gambler that has not gambled in a while or is trying to stop will exhibit withdrawal symptoms much the same as a drug addict. These withdrawal symptoms can even exhibit when a gambler is not even trying to quit, much like they do with severe drug addicts. They will often lie to family, friends, and even their own spouse regarding the extent of their problem. Often, a gambler will have to increase the amount of money wagered in order to experience the rush of gambling much like a drug addict has to increase the potency or frequency of use to keep their same high.

For many , there comes a point where they hit a wall. This may come as a result of running out of money to wager with or they may lose their job due to their gambling addiction. Sometimes, a gambler will run up such a mountain of debt to casinos, bookies, or others that they are forced to find another revenue stream to pay their debts and to continue gambling. Many times, this is when a problem gambler will turn to criminal activity.

The type of illegal activity a problem gambler engages in will depend on circumstances. The most common form of illegal activity is forgery and theft. If you look into the past of many problem gamblers, you will see this activity begin small and possibly with family or close friends. These incidents by and large may be covered up to protect the gambler in hopes they will turn things around. When they do not, they have to find others to steal from.

Fraud and embezzlement are common for white collar problem gamblers with the access to funds. Again, many times these criminal acts may start small and often the gambler “intends to pay the money back.” When their luck fails to turn around, the problem compounds and many times the embezzlement continues until records are audited or some other situation occurs that reveals that illegal activity has occurred.

Compulsive gamblers at their core have an addiction to the act of gambling like a drug addict does to crack or heroin. While it does not excuse criminal behavior when they engage in it, it at least give those investigating the crimes a better understanding behind why the crimes may have been committed.

Estimating age from blood and tooth samples: forensics method

A novel technique shown by researchers in Belgium can estimate the age of a criminal, or victim for that matter, by interpreting genetic code found in blood or tooth samples. Of course, there are many methods employed by forensic scientists that are used to estimate age, but sometimes victims might be so torn up (burned, severed limbs, etc.) that there’s no other way to estimate the age. Likewise, if the only lead a crime scene investigator has is a blood stain left over by the criminal or possibly some other DNA containing sample, then this is the only chance they have of at least profiling the age. Sometimes, this can make all the difference in the world since it narrows the search and makes police work a lot more bearable.

TDL Genetics TDL Genetics

The DNA and genetic material is not fixed, but always changing. Depending on our environment some genes might be turned on or off, and these changes in the genome can even be passed on to offsprings. The study of live DNA changes is called epigenetics. Likewise, the genome changes as we age. All our organs, for instance, are regulated by the genome so you can tell how old a person is by identifying which key genes are switched on or off, say researchers at Belgium’s University of Leuven (KU Leuven).

“The behaviour of our organs and tissues depends on which of our genes are activated,” Bram Bekaert, a forensic scientist at KU Leuven, explained in a press release. “As we grow older, some genes are switched on, while others are switched off. This process is partly regulated by methylation, whereby methyl groups are added to our DNA. In specific locations, genes with high methylation levels are deactivated.”

For now, the researchers tested this hypothesis using only four DNA methylation markers. Even so, they were able to accurately assess a person’s age using blood and tooth samples with a margin of error of 3.75 years and 4.86 years, respectively.

The findings appeared in the journal .

The show may be over, but the &# – Crime Scene Investigator (CSI) and forensics information39;CSI effect&# – Crime Scene Investigator (CSI) and forensics information39; lingers on

After more than 300 episodes spanning 15 seasons, the CBS’s crime show CSI took its final bow this Sunday. Besides being one of the most viewed drama series in television series, “CSI: Crime Scene Investigation” is also one of the most influential with good and bad. In fact, it’s so influential that people had to coin the “CSI effect” to describe how people’s opinion of how a forensic scientist or crime scene investigator does his job has changed. In most cases actually people actually found out what a crime scene investigator does, albeit short of a couple of tidbits that don’t necessarily reflect reality.

Hilariously relevant. Comic by The CSI Effect Hilariously relevant. Comic by

A prime example of the CSI effect – and there’s no greater impact – can be found in the courtroom, of all places. “With increased awareness comes a lot more expectations,” Kristine Olsson, blood spatter analyst and trace evidence scientist said. Speaking for KCTV5’s Bonyen Lee, Olsson said that the biggest misconceptions the TV show created were the timelines of test results and cracked cases. You’d think a judge would know better but Olsson claims he’s heard of many cases where DNA tests and other forensic investigations where taken for granted. “They think the results can come out in one or two minutes and crimes are solved in less than an hour on TV, including commercials,” said Allen Hamm, interim director at the Johnson County crime lab.

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At the same time, there’s a positive side to the CSI effect – publicity. Millions of young adults have become mesmerized and interested in becoming a CSI. While the show definitely romanticized the profession, schools are flooded with applications. More competition inevitably means more talent, and labs now have more qualified youth. Yes, some will definitely be disappointed past first semesters, but it’s safe to assume that a lot of people have now embarked on a career they enjoy, despite the difficulties that it entails.

Do you want to become a CSI, but not sure what this means or is required of you? Better read our guide first.

Requests for forensic medical exams increases in D.C. as sexual assault awareness grows

Positive trends have been reported in Washington – requests for forensic medical exams has increased by about 70 percent since 2010, which indicates that people are becoming more and more aware of the procedures they can turn to and are more motivated to defend their rights.

Washington Hospital Center. Image via Biz Journals.

Nurse examiners in D.C. have performed 421 exams since last October, according to Heather DeVore, president and CEO of D.C. Forensic Nurse Examiners. These forensic exams have two main functions: first, to immediately care for the rape survivor and see if there are any obvious or hidden physical injuries, and then to collect any evidence that may be useful in the investigation.

The exams are invasive but should be carried immediately (ideally under less than 30 minutes after the assault) only by specialized nurses. Included in the exam is a head-to-toe examination, hair and urine samples and examination of any injuries. In the city, there is actually a specialized task force.

Free rides

Forensic medical exams are only available in D.C. at MedStar Washington Hospital Center, and thanks to a city-funded program, victims can get to the hospital. DeVore said the availability of the exams has likely spread through “word of mouth,” but this program might have also helped.

The response of other invested agencies has also improved, thanks to continuous monitoring.

“We’re always looking at evaluating that response and looking at the agencies,” DeVore said.

Judy Malmgren, a member of the International Association of Forensic Nurses and a forensic nurse examiner in Santa Barbara, California has stated that throughout her career, the number of forensic medical exams has remained the same, and the same can be said for most of the country. It would be interesting to see what made D.C. so different.

Oregon forensic analyst investigated for tampering with drug evidence

Hundreds of cases and investigations are now in jeopardy after it was revealed that Oregon State Police (OSP) forensic analyst Nika Larsen tampered with evidence from drug cases – essentially, he stole drugs. To make things even worse, another, second  forensic analyst is now under investigation for the same thing.

Image via Wiki Commons.

Deschutes County District Attorney John Hummel said that Larsen stole drugs from the counter and then replaced them with over-the-counter pills to avoid being caught.

“I’m very concerned about the policies and procedures at the OSP crime labs in general,” Hummel said. “I want to see a major investigation by an independent agency.”

This unfortunately threatens all the cases on which Larsen worked, because it’s a case of tampering with evidence. Hummel is now going through 502 criminal cases that Larsen has worked on and has to re-evaluate all of them. But it gets even worse than this – as a forensic analyst, he had access to more evidence, not just from the cases he was working on.

“I’m very shocked to see the lack of control at the crime labs,” Hummel said. “Forensic analysts have access to all evidence, not just the evidence of the case they’re working on. We also absolutely call for an independent audit of the Oregon State Police crime labs, all of them,” Kaplan said. “We’ve actually reached out to the Attorney General with these views and the governor.”

OSP said late on Friday that a second analyst, who worked at its Central Point lab, overstate the evidence for a case in 2005. He has since retired, but an investigation is still required, as this may signal even more tampering. The OSP has some serious work to do, and the thought that this happens at more other stations is extremely worrying.

Anti-forensic malware troubles cyber-security firms

An increasing volume of attacks using file-less malware and other anti-forensic measures is leading a greater-than-ever skill gap in the cybersecurity bizz. These tehniques leave little to no trace on physical disks, and unfortunately the good guys aren’t keeping up: There’s a shortage of skilled digital forensics practitioners who are able to efficiently investigate these types of offensives.

Image via welnet-tech

“Attackers know how forensics investigators work and they are becoming increasingly more sophisticated at using methods that leave few traces behind—we are in an arms race where the key difference is training,” says Alissa Torres, founder of Sibertor Forensics and former member of the Mandiant Computer Incident Response Team (MCIRT).

Torres reports that in the last year, there has been a rise in file-less malware, programs that avoid installation on the target’s file system and operates only in it’s .

“Five years ago, to see sophisticated anti-analysis and acquisition techniques in the wild was like seeing a unicorn but that is no longer the case,” she said. “As techniques for detecting trace artefacts on a compromised system have improved, the more sophisticated attackers have adapted quickly.”

The SANS Institute estimates that possibly one in four digital forensics and incident response (DFIR) professionals has the level of training to successfully analyze the new types of self-defense techniques that include more sophisticated rootkit and anti-memory analysis mechanisms.

“The memory forensics field exploded around 2005 when a lot of the parsing tools started to become available and its use in forensics has been growing ever since,” explained Torres. “An incredible advantage this analysis method has is speed—a skilled expert in memory forensics can discover insights a lot quicker and pick up on information that is missed in traditional disk imaging.”

Although the tools at our disposal have improved, Torres pointed out that  “owning a hammer and saw doesn’t make you a carpenter—a deeper understanding of the operating system internals to include memory management allows the examiner to access target data specific to the needs of the case at hand.”

 

Forensic Psychologists Answer the Internet questions

Today, the at and world-famous, honorary member  sat down and discussed with  how psychology can improve the field of forensics, in all its aspects – in other words, they discussed about forensic psychology. Unit director , Unit co-director , Honorary member , Honorary member  and Honorary member  sat down and did an AMA – ask me anything. Here are the highlights:

Reddit user: Have there been any developments in the presentation of police lineups?

What’s better, to present the whole lineup at once, or to present lineup members one-by-one? If the latter, is it better to ask them “is this the perpetrator” after each person, or to let them see all of them and then ask for a decision?

Fiona Gabbert: Good question! People are STILL debating the best way to conduct police lineups; whether to show all of the lineup members at once, or one at a time. We refer to this as simultaneous vs. sequential lineup presentation formats. I would argue that witnesses should make an identification decision based ONLY upon their memory for the perpetrator. We know that when simultaneous lineup presentation is used, some witnesses base their decision upon comparing and contrasting against the different options, and then choosing the ‘best’ match. This might not necessarily be the person that matches their memory, but simply the best available option (clearly this can lead to errors being made). In the UK we use VIPER lineups (video-parades) where lineup members are presented one at a time, shown facing forward, then turning their face slowly to face left/right. There are some issues with the VIPER procedure, but on the whole I’m more confident in this system than the use of simultaneous lineup formats.

Dr Fiona Gabbert is an Associate Professor in Psychology at Goldsmiths University of London. She holds an M.Sc. in Social Psychology and a PhD in Applied Psychology from the University of Aberdeen.

Reddit : It appears from your summary that you are focused on minimizing wrongful convictions. Are you doing any work on methods to better spot individuals at higher risk for committing violent crime and how to address /minimize such risk? Are you working on any aspects involving rehabilitation? What have you learned that has helped improve accuracy of witness statements? Thanks for doing this. It tickles my Cultural Anthropology degree a little bit.

Lorraine Hope: With respect to the part of your question concerned with improving the accuracy of witness statement, a good deal of our work draws on memory theory to develop interviewing techniques which promote accurate and detailed reporting (and reduce the likelihood of error). So (apologies for posting some of the same response!) – the most effective investigative interviewing techniques for enhancing accurate reporting include, for example, using mental context reinstatement (instructing the witness to mentally revisit the scene), encourage a detailed and accurate account (without editing or guessing), providing retrieval support, the use of non-leading prompts and cues.

The ‘safest’ questions are Open Question (e.g. tell me everything you can about X) which allow the witness to recall their experience in their own words. The very worst kind of questions are leading questions which suggest an answer to the witness (e.g. Was the man wearing a blue jacket?). There are also some interesting new developments which explore changing the reporting format – we have promising results from some interesting studies in which we encourage people to report what they have witnessed on timelines for example. That might be an interesting question for a cultural anthropologist too!

Reddit : If you each had to pick just 1 single reform that the criminal justice system would implement overnight, what do you think is the the most important one?

Elizabeth Loftus: Near the top of my list would be blind testing in lineup situations.

Elizabeth Loftus.

Fiona Gabbert: I’m not a big fan of the jury system.

Caoinhe McAnena: I would make prison regimes more therapeutic, with increased resources for the delivery of evidence-based interventions and staff training to create more psychologically informed environments to address criminogenic needs and reduce reoffending.

Lorraine Hope: Anyone who has to elicit information from anyone should be required to have some decent interview training. I’d also quick like to see more training for legal practitioners regarding issues pertaining to witness memory to eradicate some of the inaccurate beliefs/practices (e.g. round consistency).

Reddit : I have read an article or two mentioning certain behavioral traits/characteristics being “ingrained” by a certain age. Is there any truth to this as far as a person’s proclivity for skirting the law, paying bills on time, etc? You can probably tell from my awkward phrasing that i really know nothing about this.

The first five years of life are certainly key in the development of some aspects of psychological and emotional functioning, for example in the development of secure attachments to caregivers. However it is an overstatement to say that traits are fixed at any point in human development as we possess the capacity for emotional and psychological growth and change throughout the lifespan.

Antisocial personality which is highly related to offending does have its roots in childhood and particularly adolescence and is often expressed as conduct disorder in early life. However this is influenced by ongoing social and psychological factors and these can be addressed throughout the lifespan.

Reddit : How do the victims and witnesses that are found to have been wrong in their testimony react? Many people are confident that they saw something happen in a certain way, does this no longer make them a credible witness?

Elizabeth Loftus: There is no single way people respond when they learn they are wrong. I’ve seen some people accept it. For example when told that DNA testing reveals that they had identified the wrong person, they accept it. But I’ve seen other situations where people still insist they are right.

Reddit : My question pertains to mental health professionals working within the correctional system. Here in the US it often seems that there is an emphasis on behavioral interventions within the correctional system at large and that clinicians are always viewed by inmates as a tool of the system and not as an advocate. Does any of your work focus on how clinicians can better overcome this challenge? Does any of your work focus on training correctional mental health professionals in Interpersonal Therapy or DBT for those suffering from more complex disorders? If not would you advocate for a change in treatment modalities from those that are currently in use?

In the Uk there are many examples of clinicians working therapeutically within the criminal justice system and one great example of this is the relatively new Offender PD Pathway strategy which aims to provide psychologically informed environments within prisons in order to address underlying emotional and interpersonal difficulties associated with offending. A key aspect of this service is a focus on developing a skilled workforce and this includes prison staff as well clinicians. A national framework has been developed for training staff in working with people with personality disorders which is known as the KUF in order to support this initiative.

Reddit : Do you really think that incarceration is really a good form of rehabilitation? I’ve seen on documentaries that many inmates who end up in the prison system, return. If that’s the case, and they aren’t mentally capable of handling the outside world, why haven’t we found a better solution or even integration programs (prison -> outside world). I understand that heinous crime requires harsh punishment but it seems like we could have a better solution.

Caoinhe McAnena: Incarceration in itself probably does not enable offenders to make the necessary psychological, social and other changes in order to desist from offending and lead prosocial lives in the community. However, prisons allow for the delivery of evidence based interventions aimed at changing the underlying causes of offending in many cases, such as drug and alcohol dependence, limited cognitive and decision-making skills, sexual and relationship difficulties etc etc. In the UK in the last few years a specific programme has been developed to address the issues faced by offenders with personality disorders in the prison system and it is hoped that this will reduce reoffending in that particular group. This is currently being evaluated nationally.

 

 

 

Humans experts still the best at face-matching, test finds

Face matching is, simply put, the practice of asserting if a face in a number of different pictures belongs to the same individual. And while many software companies and technology giants have invested heavily in such software (Hulu’ss facial recognition software, for example, or Facebook’s newly unveiled facial matching one), it is encouraging to see that the best of the best at it are the ones that try to protect us from those that go staby-stab in the night: forensic experts.

The first study to test the skills of FBI agents and other law enforcers who have been trained in facial recognition has provided a reassuring result – they perform better than the average person or even computers on this difficult task. The team working on the data included colleagues at the National Institute of Standards and Technology and the University of Texas at Dallas in the US, and their findings were published the Proceedings of the Royal Society B.

Image via theguardian Image via theguardian

For the study, the researchers tested an international group of 27 facial forensic examiners with many years of experience who were attending a meeting of the Facial identification Scientific Work Group. The group’s member agencies include the FBI, police and customs and border protection services in the US, Australia and other countries.

The experts were given three tests where they had to decide if pairs of images were of the same person. Their performance was compared to that of a control group of non-experts who were attending the same meeting, as well as a group of untrained students. The pairs of images used were selected to be particularly challenging, reflected in the fact that computer algorithms were 100 percent wrong on one of the tests. Participants were given either two seconds, or a more generous 30 seconds to decide depending on the test.

“Overall, our study is good news. It provides the first evidence that these professional examiners are experts at their work. They were consistently more accurate on all tasks than the controls and the students,” says White.

The findings suggest that forensic examiners trained for this task identify individuals in a different way from those that just have a knack for it, those naturally very good at face matching, the so-called super-recognizers.

“Super-recognizers tested in previous studies appear to rely on automatic, holistic processes when they compare facial images, but forensic examiners use analytical methods,” says research leader UNSW psychologist Dr. David White.

“The examiners’ superiority was greatest when they had a longer time to study the images, and they were also more accurate than others at matching faces when the faces were shown upside down. This is consistent with them tuning into the finer details in an image, rather than relying on the whole face.”

With the rise of CCTV imagery and hand-held cameras on mobile phones comes a huge pool of information that forensic experts can use. The comparison of facial features to identify suspects has thus become a powerful, efficient and important source of evidence to clear a name or imprison a felon.

“These identifications affect the course and outcome of criminal investigations and convictions. But despite calls for research on any human error in forensic proceedings, the performance of the experts carrying out the face matching had not previously been examined,” says White.

“However, it is important to note that although the tests were challenging, the images were relatively good quality. Faces were captured on high-resolution cameras, in favorable lighting conditions and subjects were looking straight at the camera,” says White. “This is often not the case when images are extracted from surveillance footage,” he went on to add.

Research collaborators included Alice O’Toole, Matthew Hill and Amanda Hahn from the University of Texas at Dallas and Jonathon Phillips from the National Institute for Standards and technology in the US.

 

Microbiomes could be the new fingerprints

A new study from researchers at the Harvard School of Public Health shows that the microbial communities each of us carries on our skin or in our bodies can be used to uniquely identify individuals, much like a fingerprint. The team behind the study showed that personal microbiomes contain enough distinguishing features to identify a person over a long amount of time from a research study population of hundreds of people. It is the first that shows microbiome identification is feasible.

Taken together, DNA sequences from four microbial species distinguish the starred person's microbiome from the microbiomes of five other people Image via hsph.harvard.edu Taken together, DNA sequences from four microbial species distinguish the starred person’s microbiome from those of five other people
Image via hsph.harvard.edu

“Linking a DNA sample to a database of DNA ‘fingerprints’ is the basis for forensic genetics, now a decades-old field.”

“We’ve shown that the same sort of linking is possible using DNA sequences from microbes inhabiting the human body — no human DNA required. This opens the door to connecting human microbiome samples between databases, which has the potential to expose sensitive subject information — for example, a sexually-transmitted infection, detectable from the microbiome sample itself,” said lead author Eric Franzosa, research fellow in the Department of Biostatistics at Harvard Chan.

More than just a gut feeling – it’s gut forensics

The team used publicly available microbiome data mined from the Human Microbiome Project (HMP), which surveyed microbe samples from stool, saliva, skin and other sites from up to 242 individuals over a month-long period. They adapted a computer algorithm to crunch the data and obtained combinations of stable and distinguishing sequence features from the initial samples that work as individual-specific “codes”.

When compared to microbiome samples collected at follow-up visits with the same individuals and to samples from independent groups of individuals, the codes were shown to be unique among hundreds of individuals. A large fraction of the microbial signature remained stable over a one-year sampling period, those obtained from gut samples in particular. Here, more than 80% of individuals could be identified without a trace of doubt for up to a year after the sampling period.

“Although the potential for any data privacy concerns from purely microbial DNA is very low, it’s important for researchers to know that such issues are theoretically possible,” said senior author Curtis Huttenhower, associate professor of computational biology and bioinformatics at Harvard Chan School. “Perhaps even more exciting are the implications of the study for microbial ecology, since it suggests our unique microbial residents are tuned to the environment of our body — our genetics, diet, and developmental history — in such a way that they stick with us and help to fend off less-friendly microbial invaders over time.”