JUNEAU, Alaska (AP) — Sarah Palin on Friday shook up an already unpredictable race for Alaska's lone U.S. House seat, filing paperwork to join a field of at least 40 candidates seeking to fill the seat that had been held for 49 years by the late-U.S. Rep. Don Young, who died last month.

Palin filed paperwork Friday with a Division of Elections office in Wasilla, said Tiffany Montemayor, a division spokesperson. The paperwork was being processed by the division, she said.

The field includes current and former state legislators and a North Pole city council member named Santa Claus. The deadline...