Читать книгу Principles of Virology - Jane Flint, S. Jane Flint - Страница 123

 The genomes of viruses range from the extraordinarily small (<2 kb) to the extraordinarily large (>2,500 kbp); the diversity in size likely provides advantages in the niches in which particular viruses exist.

 Viral genomes specify some, but never all, of the proteins needed to complete the viral reproductive cycle.

 That only seven viral genome replication strategies exist for all known viruses implies unity in viral diversity.

 Some genomes can enter the reproduction cycle upon entry into a target cell, whereas others require prior repair or synthesis of viral gene products before replication can proceed.

 Although the details of replication differ, all viruses with RNA genomes must encode either an RNA-dependent RNA polymerase to synthesize RNA from an RNA template or a reverse transcriptase to convert viral RNA to DNA.

 The information encoded in viral genomes is optimized by a variety of mechanisms; the smaller the genome, the greater the compression of genetic information.

 The genome sequence of a virus is at best a biological “parts list” and tells us little about how the virus interacts with its host.

 Technical advances allowing the introduction of mutations into any viral gene or genome sequence are responsible for much of what we know about viruses.