Complex sentence: She revealed a natural affinity for music at an early age, but was overshadowed by the talents of her younger sister Jackie, a celebrated 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.