ending changed ** SPOILER **
The concluding comments discussed children born to the families of Tertius and Rosamond, and of and Fred and Mary Vincy, with no mention of any children for Dorothea and Will. The finale of the book (that can be found online at http://www.19thnovels.com/middlemarch.php?c=87), mentions Dorothea's son who will later inherit the Brooke estate when her uncle dies after a long life.
The omission robs us of knowing that Dorothea's legacy will not die with her. It may have been done to focus on the importance of those who live faithful hidden lives, and rest in unvisited tombs.