I would expect Gephi GML loader would admit scientific notations, but it doesn't. Scientific notation is prescribed in the GML official specification (see page 2):
http://www.fim.uni-passau.de/fileadmin/files/lehrstuhl/brandenburg/projekte/gml/gml-technical-report.pdf

Sample file:
graph [
directed 0

node [
    id 3719161
    label "GGNBP2"
]
node [
    id 3719150
    label "PIGW"
]
edge [
    source 3719161
    target 3719150
    CtrlRSq 0.03564458751187731
    CasePVal 0.36896971076737917
    CtrlPVal 6.870900696337445E-4
    CaseRSq 0.006731404647102828
]

]

Imported from Launchpad using lp2gh.

• date created: 2011-02-01T23:20:56Z
• owner: robbyjo
• assignee: sebastien.heymann
• the launchpad url was https://bugs.launchpad.net/bugs/711569