Japanese Guts Are Made For Sushi

cremeglace writes "Americans don't have the guts for sushi. At least that's the implication of a new study, which finds that Japanese people harbor enzymes in their intestinal bacteria that help them digest seaweed, enzymes that North Americans lack. What's more, Japanese may have first acquired these enzymes by eating bacteria that thrive on seaweed in the open ocean."

Comments

population sample

[networkzombie]

Czjzek's team compared the microbial genomes of 13 Japanese people with those of 18 North Americans.
If I used this many test subjects in my job I would get fired.

babies

[thoughtsatthemoment]

The study maybe valid if they can find the enzymes in Japanese babies. Otherwise it can be said that the Japanese have the enzymes because they eat lots of sushi.

But then it makes no sense

[Moraelin]

But then it makes no sense to say they acquired it from bacteria.

Genes don't transfer from bacteria to mammals. Genes transfer between bacteria, via exchange of plasmids. (Which is one reason why antibiotic resistance spreads so fast.) But your cells don't have the mechansims to acquire such a plasmid, and wouldn't know what to do with it. You don't even have the regulating proteins or the ribosome to deal with a _circular_ DNA strand, and one outside the nucleus at that.

At this point someone will probably have the knee-jerk reaction to explain how viruses can account for horizontal gene transfer, 'cause they read that notion at some point and it sounded so smart. Not so fast. Viruses are quite specialized in what they attach to. They depend on very specific nucleotid sequences, which is why you can have a virus that attacks your upper respiratory tract, but can't affect your lungs, or viceversa. Viruses that prey on bacteria, the so called "phages", have very specialized capsids and mechanisms to inject themselves into a bacterium, and are even more specialized in what they can attach to. Which is why for example you can spray meat with a phage which destroys Lysteria, but won't destroy your intestinal flora. A virus that's suited to infect both a bacterium _and_ your gut lining and transfer genes from one to the other, is almost an impossibility, and at any rate to the best of my knowledge none was ever identified.