Imagine You Are Studying an Expanded Gene Family in a Group

Essay

Imagine you are studying an expanded gene family in a group of closely related species,and you would like to know whether the gene family expanded long ago in the common ancestor of all the species,or whether the gene family has expanded independently,and more recently,within some or all of the species.How would you use DNA sequences from the gene family in each species to test this? (Hint: Evolutionary trees are required.)