Hi,

Thanks to all who helped.
With the help this is the final code that I came up with.

Code:
Sub Refseq()
Dim Mval As String
Dim i As Long
Dim lrow As Long
Sheets("Sheet2").Activate
lrow = Sheets("Sheet2").Range("A65536").End(xlUp).Row
For i = 2 To lrow
    Range("G" & i) = Range("F" & i) & ":" & CSPLIT(Range("B" & i))
Next
End Sub

Function CSPLIT(strPassed As String) As String

    Dim str, strP As String
    strP = Split(strPassed, ";")(0)
    str = Split(strP, ">")(0) & ">"
    If InStr(1, Split(strPassed, ";")(0), "/") Then
        str = str & Split(Split(strPassed, ";")(0), "/")(1)
    Else
        str = str & Right(Split(strPassed, ";")(0), 1)
    End If
    CSPLIT = str
    
End Function