This lesson covers the Mission to the Lamanites.
I discussed this lesson separately on another blog, so I'll repost that here.
The demographics of Latin America show that, apart from the indigenous populations (Amerindians) whose ancestry is north Asian (mtDNA Haplogroups A, B, C, and D), the ancestors of most of the population originated in Europe. It was the incongruence between the DNA evidence and Orson Pratt's hemispheric model (Lamanites are the ancestors of all the Latin Americans) that caused such confusion and led to rewording the Introduction to the Book of Mormon from "principal ancestors" to "among the ancestors" of the American Indians. Introduction (churchofjesuschrist.org)