+Identifying core genes is important to understand evolutionary and
+functional phylogenies. Therefore, in this work we present methods to
+build a genes content evolutionary tree. More precisely, we focus on
+the following questions considering a collection of 99~chloroplasts
+annotated from NCBI \cite{Sayers01012011} and Dogma \cite{RDogma}: how
+can we identify the best core genome and what is the evolutionary
+scenario of these chloroplasts.
