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.
In the western Pacific the countercurrent is centered near 5Â°N while in the central Pacific it is located near 7Â°N. The northern boundary of the Pacific NECC is easily defined by the adjacent westward flow found in the North Equatorial Current (NEC). The southern boundary, however, can be more ambiguous.