Characterization of adenovirus genome type 7h: analysis of its relationship to other members of serotype 7.

Ad7h is a newly identified genome type associated with severe lower acute respiratory infections and has so far been isolated only in South America. To obtain a clue to its possible origin, the degree of restriction enzyme site homology between adenovirus genome type 7h and those representative of the three described genomic clusters (GC) for serotype 7 was studied by analysis of pairwise comigrating DNA restriction fragments (PCRF) after digestion with BamHI, BglI, BglII, BstEII, EcoRI, HindIII, HpaI, SalI, SmaI, XbaI, and XhoI. The most closely related genome types, Ad7b, Ad7d, and Ad7g, displayed 85.7, 83.8, and 82.8% comigrating fragments, respectively. Ad7p (GC1) was clearly distant with only 68.6% PCRF. No remarkable close genetic relationships (%PCRF greater than 90) were observed with any of the genome types grouped within GC3 or with Ad7g (the only member of GC2), so since Ad7h seems to be related to both members of GC2 and GC3, it could equally be considered to represent a new cluster or to end up grouped in either GC2 or GC3, depending on the results of further analysis.