Sentence 1: A fourth daughter , Leonora , was the step-great-grandmother of astronomer and astrophysicist Cecilia Payne-Gaposchkin .
Sentence 2: A fourth daughter , Leonora , was the stepmother of astronomer and astrophysicist Cecilia Payne-Gaposchkin .
Question: Do Sentence 1 and Sentence 2 express the same meaning? Yes or No?