Yes, if your spouse paid the mortgage, she may claim the deduction.  Otherwise, if it was paid from joint funds, you may split it to be reported on both returns.

Please take a look at the following information from the IRS regarding splitting itemized deductions when using the Married Filing Separate filing status:  https://www.irs.gov/help-resources/tools-faqs/faqs-for-individuals/frequently-asked-tax-questions-an...