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.
El NiÃ±o and La NiÃ±a are the opposite phases of ENSO (pronounced en-so), which is short for El NiÃ±o-Southern Oscillation. Operating in the tropical Pacific Ocean, ENSO is Earth's singlest most influential natural climate pattern.