Reverse transcriptase is characteristic of retroviruses, including HIV (human immunodeficiency virus), the virus responsible for AIDS (acquired immunodeficiency syndrome). All retroviruses encode a polymerase enzyme in their pol gene that is both necessary and sufficient for the replication of their RNA genomes.
PDO positive phase global pattern. The Pacific Decadal Oscillation (PDO) is a robust, recurring pattern of ocean-atmosphere climate variability centered over the mid-latitude Pacific basin.
Pacific Crest Bicycle Trail. The Pacific Crest Bicycle Trail (PCBT) is a 2,500-mile-long, road-based bicycle touring route from Vancouver, British Columbia, Canada to Tijuana, Baja California, Mexico. It was designed to closely parallel the Pacific Crest Trail and the two trails cross 27 times as they pass through the states of Washington, Oregon, and California.