Diet might still be major: they say their predictive model got ethnicity right 62% of the time, from the bacterial info. I suspect that you could also predict ethnicity better than chance from diet logs.
To really tease out the genetic influence, you'd want to standardize diet, and give all strains equal chance to colonize. Perhaps, compare cohabiting similar-diet same-sex kissing-partners of different-ethnicities, after an initial palate-cleansing course of antibiotics? It's the only way to be sure!
This is different than I thought:
"The variation along ethnic lines, they believe, is a reflection of genetics, not environment."
Taking one example that I know a little about. Korea. I would think that environmental impact would include things like the type of probiotic foods they eat - like kimchi, fermented soybeans and fermented fish would affect the flora and fauna in their mouth.
Also eating habits - Koreans will often share a soup container and side dishes where everyone sticks their chopsticks and soupspoons into a shared pot,
These things would affect the types of bacteria in their bodies I would think...
This doesn't surprise me. People of different ethnicities smell subtly different, which either comes from the bacteria or else it means there are different chemicals available to the bacteria, probably both.
I wonder how (if at all) this might be tied to recent findings about gut bacteria and obesity.
We're still just scratching the surface in terms of our understanding of the human body. Doctors in 2113 will be as horrified by some of our early 21st century medical practices and recommendations as we are of the Downton Abbey era of medicine.
They're not sure whether this stems from genetics or environment - they say they think it's genetics, but there might be a simple environmental explanation:
The main way people exchange mouth bacteria is through dating, and there's a huge tendency to date people of similar ethnicity.
It's human nature, it's in our DNA. People like to hang out w/ those that look like them, they feel more comfortable. Yes there are outliers here and there, but for the most part, I can bet 70%+ of the people reading this are as follows: if you are Asian, I bet most of your good friends are Asian, if you white, then most of your good friends are white, and so on and so forth. It's not racism, it's just human nature that starts early on. If you grew up in America you know what I'm talking about, ever notice how young kids including yourself start naturally forming groups late in elementary school? if not then definitely around middle school. Whites hang out with the whites, Asians hang out with the Asians, Latinos w/ Latinos, blacks w/ blacks, etc..
I don't think that was being questioned at any point. The comment is about whether people share similarities in their microbiome because of their genetic background or because they hang around with people generally of the same background.
"Instead, people's background—in terms of foods they ate and other lifestyle trends—didn't seem to have any correlation with the bacterial communities in their mouths."
I wondered about general interaction and intimacy too, but there doesn't seem to be enough info to make a call either way. The quote above doesn't really cover it. "Lifestyle trends" doesn't really cover interacting with each other.
The main way people exchange mouth bacteria is through dating
This is not correct. During birth, babies are exposed to their mother's vaginal fluid which then transfers bacteria into the baby's mouth. This transfer introduces a nice bacterial balance and makes it more difficult for a single species of bacteria to monopolize the mouth and digestive system. This exchange doesn't occur when babies are born via C-section, so doctors usually swab some of the mothers vaginal fluid in the baby's mouth so he will also have a healthy balance of bacteria.
So only 4 US ethnicities were tested: African Americans, Caucasians, Chinese and Latinos. That feels extremely broad - especially "Chinese" and "African Americans" combine many, many different genetic groups. Edit: The Chinese government, for example, recognizes 56 ethnic groups, which may or may not genetically be distinct.
>The subgingival microbial community was able to predict an individual’s ethnicity with a 62% accuracy, 58% sensitivity and 86% specificity.
Wait, that doesn't seem very good - I could flip a dented coin and get similar results?
The chinese government recognizes many ethnic groups, but Chinese are overwhelmingly Han, and less genetically diverse than Caucasians. Why are you more worried about the chinese group than the caucasian group?
> I could flip a dented coin and get similar results?
No idea what you're trying to say there, but (a) there's a fun paper out there essentially showing that it's not possible to bias a coin; (b) in the absence of demographic information on the community, a biased coin is no better or worse than an unbiased one; and (c) yes, you can obviously do enormously better at distinguishing american whites, american blacks, american chinese, and american latinos, than those figures. But chance would predict ethnicity with 25% accuracy, so they're doing a lot better than that.
What's with the popular usage of latino or hispanic as a separate race?
From wiki:
"The United States Census uses the ethnonym Hispanic or Latino to refer to "a person of Cuban, Mexican, Puerto Rican, South or Central American, or other Spanish culture or origin regardless of race."
Also, remember that there are many white/caucasian people in Mexico and other latin american countries that also are hispanic. Ricky Martin is an obvious example of a white Puerto Rican, for instance.
I am not saying a mestizo should necessarily be classified as "white", but there seems to be an idea these days that hispanics are a separate race, which is incorrect.
> What's with the popular usage of latino or hispanic as a separate race?
Mostly that came from the US government deciding to create a pressure group by lumping various central and south american nationalities together.
However, US hispanics do form a group which is noticeably different from, say, US whites. Many are indios. In particular, we get a huge amount of mexican immigration, but it's mostly the poor mexicans who choose to come. White mexicans are generally doing pretty well in Mexico.
> there seems to be an idea these days that hispanics are a separate race, which is incorrect.
This depends on what level of population structure you want to label "race". It's not difficult to distinguish US hispanics from US whites with a genetic test; that's a good enough marker of "race" for me. As you point out, the category has a lot more mixing than you might expect in another racial group, such as Germans, but it's still a workable category.
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[ 3.2 ms ] story [ 63.8 ms ] threadThe average hand has about 150 different species, with only about 17% of those also appearing on the other hand of the same person. [1]
[1] http://msms.ehe.osu.edu/2012/02/29/how-many-bacteria-species...
To really tease out the genetic influence, you'd want to standardize diet, and give all strains equal chance to colonize. Perhaps, compare cohabiting similar-diet same-sex kissing-partners of different-ethnicities, after an initial palate-cleansing course of antibiotics? It's the only way to be sure!
This is different than I thought: "The variation along ethnic lines, they believe, is a reflection of genetics, not environment."
Taking one example that I know a little about. Korea. I would think that environmental impact would include things like the type of probiotic foods they eat - like kimchi, fermented soybeans and fermented fish would affect the flora and fauna in their mouth.
Also eating habits - Koreans will often share a soup container and side dishes where everyone sticks their chopsticks and soupspoons into a shared pot,
These things would affect the types of bacteria in their bodies I would think...
We're still just scratching the surface in terms of our understanding of the human body. Doctors in 2113 will be as horrified by some of our early 21st century medical practices and recommendations as we are of the Downton Abbey era of medicine.
The main way people exchange mouth bacteria is through dating, and there's a huge tendency to date people of similar ethnicity.
I wondered about general interaction and intimacy too, but there doesn't seem to be enough info to make a call either way. The quote above doesn't really cover it. "Lifestyle trends" doesn't really cover interacting with each other.
This is not correct. During birth, babies are exposed to their mother's vaginal fluid which then transfers bacteria into the baby's mouth. This transfer introduces a nice bacterial balance and makes it more difficult for a single species of bacteria to monopolize the mouth and digestive system. This exchange doesn't occur when babies are born via C-section, so doctors usually swab some of the mothers vaginal fluid in the baby's mouth so he will also have a healthy balance of bacteria.
See here for more info
http://www.usnews.com/science/articles/2010/06/22/babys-firs...
kord@brush:~$ ssh -i .ssh/id-halitosis teeth
So only 4 US ethnicities were tested: African Americans, Caucasians, Chinese and Latinos. That feels extremely broad - especially "Chinese" and "African Americans" combine many, many different genetic groups. Edit: The Chinese government, for example, recognizes 56 ethnic groups, which may or may not genetically be distinct.
>The subgingival microbial community was able to predict an individual’s ethnicity with a 62% accuracy, 58% sensitivity and 86% specificity.
Wait, that doesn't seem very good - I could flip a dented coin and get similar results?
> I could flip a dented coin and get similar results?
No idea what you're trying to say there, but (a) there's a fun paper out there essentially showing that it's not possible to bias a coin; (b) in the absence of demographic information on the community, a biased coin is no better or worse than an unbiased one; and (c) yes, you can obviously do enormously better at distinguishing american whites, american blacks, american chinese, and american latinos, than those figures. But chance would predict ethnicity with 25% accuracy, so they're doing a lot better than that.
From wiki: "The United States Census uses the ethnonym Hispanic or Latino to refer to "a person of Cuban, Mexican, Puerto Rican, South or Central American, or other Spanish culture or origin regardless of race."
Also, remember that there are many white/caucasian people in Mexico and other latin american countries that also are hispanic. Ricky Martin is an obvious example of a white Puerto Rican, for instance.
I am not saying a mestizo should necessarily be classified as "white", but there seems to be an idea these days that hispanics are a separate race, which is incorrect.
Mostly that came from the US government deciding to create a pressure group by lumping various central and south american nationalities together.
However, US hispanics do form a group which is noticeably different from, say, US whites. Many are indios. In particular, we get a huge amount of mexican immigration, but it's mostly the poor mexicans who choose to come. White mexicans are generally doing pretty well in Mexico.
> there seems to be an idea these days that hispanics are a separate race, which is incorrect.
This depends on what level of population structure you want to label "race". It's not difficult to distinguish US hispanics from US whites with a genetic test; that's a good enough marker of "race" for me. As you point out, the category has a lot more mixing than you might expect in another racial group, such as Germans, but it's still a workable category.