Yes you both can fill the forms seprately.

Here's the reference from the instruction file available at this link:

http://www.travel.state.gov/pdf/2009DVInstructions.pdf

It says:

10. MAY A HUSBAND AND A WIFE EACH SUBMIT A SEPARATE ENTRY?

Yes, a husband and a wife may each submit one entry if each meets the eligibility requirements. If either were

selected, the other would be entitled to derivative status.