  The ongoing global pandemic of infection disease COVID-19 caused by the 2019
novel coronavirus (SARS-COV-2, formerly 2019-nCoV) presents critical threats to
public health and the economy since it was identified in China, December 2019.
The genome of SARS-CoV-2 had been sequenced and structurally annotated, yet
little is known of the intrinsic organization and evolution of the genome. To
this end, we present a mathematical method for the genomic spectrum, a kind of
barcode, of SARS-CoV-2 and common human coronaviruses. The genomic spectrum is
constructed according to the periodic distributions of nucleotides, and
therefore reflects the unique characteristics of the genome. The results
demonstrate that coronavirus SARS-CoV-2 exhibits dinucleotide TT islands in the
non-structural proteins 3, 4, 5, and 6. Further analysis of the dinucleotide
regions suggests that the dinucleotide repeats are increased during evolution
and may confer the evolutionary fitness of the virus. The special dinucleotide
regions in the SARS-CoV-2 genome identified in this study may become diagnostic
and pharmaceutical targets in monitoring and curing the COVID-19 disease.
