LONDON : Sauber's signing of Brazilian Gabriel Bortoleto means at least a fifth of the 20 driver Formula One grid will be starting a first full season in 2025 with a new wave of young talent coming up fast. "We are currently witnessing a generational shift in Formula One, with young drivers immediately making an impact," said Sauber Motorsport chairman and Audi chief executive Gernot Dollner in a statement announcing Bortoleto's arrival. Bortoleto, 20, will be lining up against fellow rookies