Winning isn't contagious. Penalties and mistakes apparently are.

The Denver Broncos, who had hoped to put together a modest winning streak to take the edge off a dismal season, lost 17-12 to the Seattle Seahawks Sunday night in appropriate fashion. They ended the game with a mistake.With no time left on the clock, wide receiver Michael Young was dancing in the end zone, the apparent hero after catching a 49-yard Hail Mary pass from quarterback John Elway. His teammates were dancing on the sideline.

And officials were gathering around the flags they had thrown.

The Broncos were called for illegal motion because two wide receivers were not set when the ball was snapped. Game, Seahawks. Reality, Broncos.

One play told a story about a season.

"It's kind of typical of our whole year," Broncos coach Dan Reeves said.

"1990," Elway said.

The Broncos, who had snapped a six-game losing streak with a victory last week, fell to 4-11. The Seahawks, meanwhile, improved to 8-7, keeping alive their chances for a playoff berth. They have to win next week at home against the Detroit Lions to have a chance at a wild-card berth in the AFC.

They certainly gave the Broncos every chance to give them an early off-season in a wild game at the Kingdome. Young said he had a good idea when he pushed off the line of scrimmage that something was rotten on the final play. Referee Jim Tunney said the two wide receivers in front of the head linesman - Young and rookie Shannon Sharpe - were moving before the snap.

"The minute I took off I knew there was a chance there was a flag," Young said. "I looked downfield after I caught it and I pretty much knew what it was for.

" ... It (the catch) would have been something to remember for a long time. Now, it's hopefully something I can get rid of from my memory. I can't believe it. It's just disgusting."

But for the Broncos, it shouldn't have come to that anyway. In the closing minutes, they had three opportunities and squandered each of them.

"Mistakes are the thing that are plaguing us - dropped passes, (bad) execution," Reeves said.

The Broncos had a chance to cut into the Seahawks' lead with 9:26 left in the game, but David Treadwell was wide right on a 45-yard field goal attempt, his second miss of the game.

They had a chance to win the game late in the fourth quarter, but a dropped pass by wide receiver Mark Jackson and a sack by Jacob Green for an 8-yard loss on third-and-11 near midfield ended those ideas.

Jackson was wide open along the left sideline. A moment later, he was alone with his thoughts as the ball bounced off his hands and onto the carpet.

Opportunity No. 3 presented itself when the Broncos took over with 3:01 left in the game. But Seahawks cornerback Melvin Jenkins, who had played only briefly in the game, intercepted an Elway pass that was intended for Young but had a mind of its own.