SPADA

Maximum likelihood analysis of single nucleotide

matrices (

Variola virus

)

NON-

WEST

AFRICA

BANGLADESH

NEPAL

INDIA

SUMATRA

MIDDLE

EAST

EAST ASIA

ORIENT

WAFRICA

BRAZIL

isolates passaged

2-3 times to

high titer master

seed

stocks

DNA extracted

Sequenced using

primer walking

methodology

Li Y.et.al.PNAS 2007;104:15787-15792 Esposito et. al Science 2006

Asian

Variola

major

Alastrimminor

African

minor

AND

African

major

Diversity of

Variola virus

~200 kb dsDNA, ~200 ORFs

•

Diversity of

Variola virus

strains is associated with geographic distance

•

Alastrimminor (South America) / Variola major (Asia):

~600 SNPs, ~80 Indels

•

Alastrimminor / Variola intermediate (West Africa):

~350 SNPs, ~45 Indels

•

Variola African minor/major / Variola major (Asia):

~150 SNPs, ~30 Indels

•

Central region: virion structural proteins, enzymes - 30 gene sequences are

perfectly conserved or have only synonymous SNPs, highly conserved,

essential function.

•

Left and Right end regions: Host range and immunomodulatory genes -

majority of Indels/frameshift mutations, fragmented sequences,

additional/absent of ORFs, - likely reflecting selection pressures.

•

Versus other

Orthopoxviruses

•

Variola / Camelpox-Taterapox viruses

~3200 SNPs, ~380 Indels

•

Variola / Monkeypox virus

~7500 SNPs, ~600 Indels