[o0CY0o]

Dear all,

I am here to ask about what is the relationship between the "2 strains in DNA not directly opposite to each other " to that of the different length of the major and minor groove.

Please help.

Best regards,
Jeromy

[Wreath]

I'm not really sure if I got the question, but I'll try.
You can recognize major/minor groove by numbering the atoms in purines/pyrimidines. Minor groove is the one which is on the purine/pyrimidine side which have small numbers, major groove is on the large numbers side. It's the only way you can recognize them for sure, I believe.
Major groove has the complete chemical information about the bases, it can be recognized by following the structures like methyl groups, H-bond donors/acceptors. In minor groove, there can not be recognized the concrete base pair just by following this "chemical signs".
If you call the groove major/minor does not depend on size of the groove.