Complex sentence: She revealed a natural affinity for music at an early age, but was overshadowed by the talents of her younger sister Jackie, the famed cellist whose life and career were cut short by multiple sclerosis.
Split into simpler sentences: She revealed a natural affinity for music at an early age, but was overshadowed by the talents of her younger sister Jackie. The latter became a famed cellist whose life and career were cut short by multiple sclerosis.