The researchers, led by Sarah Lewis from the University of Bristol, UK investigated the results of five published studies which looked at the association between blood pressure and a variation in the gene for the enzyme that removes alcohol from the body, aldehyde dehydrogenase 2 (ALDH2). People who inherit two copies of the variant form of this gene from their parents have the ALDH2 *2*2 genotype and become flushed and nauseated after drinking. Consequently, they drink less than people with a *1*2 genotype and much less than those with a *1*1 genotype. Because inheritance of these genetic variants does not seem to affect lifestyle factors other than alcohol intake, an association between ALDH2 genotypes and blood pressure would indicate that alcohol intake has an effect on blood pressure.
The studies were mainly done in Japan where the ALDH2 gene variant is common. A combined (meta) analysis showed that men with the *1*1 genotype (and hence highest alcohol intake) and those with the *1*2 genotype (intermediate alcohol intake) were 2.42 and 1.72 times more likely, respectively, to have hypertension than those with the *2*2 genotype (lowest alcohol intake). There was no association between ALDH2 genotype and hypertension among the women in these studies because they drank very little.
These findings support the suggestion that alcohol has a marked effect on blood pressure, at least for Japanese men. Additional large-scale studies are needed to confirm the finding in more people, and to improve the estimates of the effect that alcohol intake has on blood pressure.
Citation: Chen L, Davey Smith G, Harbord R, Lewis SJ (2008) Alcohol and blood pressure: A systematic review implementing a mendelian randomization approach. PLoS Med 5(3): e52.
medicine.plosjournals/perlserv/?request=get-document&doi=10.1371/journal.pmed.0050052
Stromatolite samples collected from two pozas in 2004 were examined by several co-authors in the research group of San Diego State University biologist Forest Rohwer, who has prepared the world's largest database of phage DNA. In the first step of the tests, researchers crushed small bits of the coral-like stromatolites and extracted DNA from the samples. The DNA from each sample was decoded and compiled into a database called a "metagenome." The metagenomes from the Mexican pozas were compared with each other and with metagenomes from stromatilites in Highborne Cay, Bahamas. Finally, all three of these metagenomes were compared with Rohwer's phage database and with several large gene-sequence databases, like GenBank.
"Taken together, these results prove that viruses in modern microbialites display the variability of distribution of organisms on our planet," Rohwer said. "It also suggests that they may be derived from an ancient, microbial community."
The analyses found that the phages in the Bahamas and in both Mexican pozas shared only about 5 percent of the same DNA sequences. Moreover, the analyses revealed that the Mexican phages appeared to have evolved from ancient, ocean-going relatives. Siefert said the finding is amazing given that Cuatro Ci?Šnegas has been cut off from the ocean for about 100 million years, but it complements prior findings of marine genetic signatures in some of Cuatro Ci?Šnegas' other endemic species.
"Over that length of time, we would expect the marine signature to get washed out of the genetic code," she said. "In fact, when we compared the phages from the pozas to oceanic phages, we found cases where the pozas' phages were more closely related to marine relatives than were some of the phages found in other oceans."
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