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 107~chloroplasts
+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.