Complex sentence: Due to the father-son dynamics of the hunting world depicted in the series' first season with the Winchesters, the writers decided to explore a mother-daughter relationship, resulting in the introduction of Jo--originally named Alex--and her mother Ellen.
Split into simpler sentences: Due to the father-son dynamics of the hunting world depicted in the series' first season with the Winchesters, the writers decided to explore a mother-daughter relationship. This resulted in the introduction of Jo--originally named Alex--and her mother Ellen.