NEW YORK, April 17 - Researchers at Howard Hughes Medical Institute said today they have sequenced the genomes of 10 newly identified viruses found in the monkey pit at a zoo in New York City and other locations.
The viruses, called mycobacteriophages, are known to infect "a range of bacteria," including those that cause tuberculosis and leprosy, according to the researchers. The scientists, helped by high school students from Pennsylvania and New York, have also found evidence that these viruses undergo "constant random genetic mixing" in the wild.
The 10 soil-dwelling mycobacteriophages selected for genomic sequencing came from zoos, backyards, and the soil outside a tuberculosis sanitarium in India, the researchers said in their study, which appears in the April 18 Cell.
Until now, scientists had only characterized the complete genomes of four mycobacteriophages, the researchers said in a statement. The genomic sequences of the 10 new phages "may offer important information to researchers," said Graham Hatfull, an HHMI professor and co-author of the study.
"Of those phages that we had genomic sequence information for, the morphologies were rather similar to those that we'd seen previously," he said. "However, when viewed under the electron microscope, the morphologies of these newly isolated phages were quite a bit more varied than we had imagined. These surprising findings should give us new information about the relationship between genomic information and viral morphologies."
Led by Hatfull, the team enlisted the help of high school biology students taught by Jacobs's sister, Debbie Jacobs-Sera, also a co-author of the article. One student isolated a phage from the rosebush in her front yard and from a nearby barnyard, while another student found a phage in soil from the Bronx Zoo monkey pit, in New York City, Jacobs writes.
"We were somewhat surprised by the variety of genome lengths," said Hatfull. "The previously sequenced mycobacteriophage genomes were about in the same range, but these new ones varied as much as threefold, and they didn't appear to fall into any discrete groups."
His group also found that the length of the phage genomes appeared to be statistically correlated with the percentage of the DNA bases guanine and cytosine--"a mystery that will take some time to figure out," the researchers write.
The new phages exhibited an extraordinary genomic diversity, said Hatfull. "Some of these new phages are clearly very different in terms of their sequence information from any of the other phages that we've isolated," he explained. "That suggests that if we extrapolate to the huge group of phages as a whole, they are more diverse than we ever imagined they could be."