Szybalski's rule

Szybalski's rule says that lower-protein particles like viruses contain more purines than pyrimidine in their nucleic acid sequence.[1] This is to prevent double-stranded RNA formation of one or two separate RNA strand that have complementary regions. The formation of a double-stranded RNA is not efficient for viruses as it may delay or stop RNA replication or protein formation.[2] The rule is named for Wacław Szybalski.

References

1. Szybalski, Wacław, Kubinski H, Sheldrick O (1966). "Pyrimidine clusters on the transcribing strand of DNA and their possible role in the initiation of RNA synthesis". Cold Spring Harb Symp Quant Biol. 31: 123–127. doi:10.1101/SQB.1966.031.01.019. PMID 4966069.
2. Lao P, Forsdyke D (2000). "Thermophilic Bacteria Strictly Obey Szybalski's Transcription Direction Rule and Politely Purine-Load RNAs with Both Adenine and Guanine". Genome Res. 10 (2): 228–236. doi:10.1101/gr.10.2.228. PMC 310832. PMID 10673280.