Climatic-niche evolution of SARS-CoV-2

COVID-19 pandemic has been extensively studied by many researchers. However, it is still unclear why it was restricted to higher latitudes during the initial days and later cascaded in the tropics. Here, we analyzed 176 SARS-CoV-2 genomes across different latitudes and climate (Koppens climate) that provided insights about within species virus evolution and its relation to abiotic factors. Two genetically variant groups, named as G1 and G2 were identified, well defined by four mutations. The G1 group (ancestor), is mainly restricted to warm and moist, temperate climate (Koppens C climate) while its descendent G2 group surpasses the climatic restrictions of G1, initially cascading into neighboring cold climate (D) of higher latitudes and later into hot climate of the tropics (A). It appears that the gradation of temperate climate (Cfa-Cfb) to cold climate (Dfa-Dfb) drives the evolution of G1 into G2 variant group which later adapted to tropical climate (A) as well. It seems this virus followed inverse latitudinal gradient in the beginning due to its preference towards temperate (C) and cold climate (D). Our work elucidates virus evolutionary studies combined with climatic studies can provide crucial information about the pathogenesis and natural spreading pathways in such outbreaks which is hard to achieve through individual studies. Mutational insights gained may help design an efficacious vaccine. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/147074v3_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@f39a3org.highwire.dtl.DTLVardef@1910598org.highwire.dtl.DTLVardef@6516corg.highwire.dtl.DTLVardef@cbb48c_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefThe authors elucidate adaptation of SARS-CoV-2 to different climates by studying phylogenetics and the distribution of strains on Koppens climate map. HighlightsO_LIPhylogenetic network divides SARS-CoV-2 strains into two variant groups, G1 and G2. C_LIO_LIG1 strains is restricted to Koppens "temperate" climate (mainly Cfa-Cfb). C_LIO_LIG2 strains has evolved from G1 to sustain in other climates mainly "humid-continental" (Dfa-Dfb) and "tropical-savannah" (Aw) climate. C_LI