-The field of genome annotation pays a lot of attentions where the ability to collect and analysis genomical data can provide strong indicators for the study of life\cite{Eisen2007}. Four of genome annotation centers (such as, \textit{NCBI\cite{Sayers01012011}, Dogma \cite{RDogma}, cpBase \cite{de2002comparative}, CpGAVAS \cite{liu2012cpgavas}, and CEGMA\cite{parra2007cegma}}) present various types of annotation tools (\emph{i.e.} cost-effective sequencing methods\cite{Bakke2009}) on different annotation levels. Generally, previous studies used one of three methods for gene finding in annotated genome using these centers: \textit{alignment-based, composition based, or combination of both\cite{parra2007cegma}}. The alignment-based method is used when we try to predict a coding gene (\emph{i.e.}. genes that produce proteins) by aligning DNA sequence of gene to the protein of cDNA sequence of homology\cite{parra2007cegma}. This approach also is used in GeneWise\cite{birney2004genewise}. Composition-based method (known as \textit{ab initio}) is based on a probabilistic model of gene structure to find genes according to the gene value probability (GeneID\cite{parra2000geneid}). In this section, we consider a new method of finding core genes from large amount of chloroplast genomes, as a solution of the problem resulting from the method stated in section two. This method is based on extracting gene features. A general overview of the system is illustrated in Figure \ref{Fig1}.\\
+The field of genome annotation pays a lot of attentions where the
+ability to collect and analysis genomical data can provide strong
+indicators for the study of life\cite{Eisen2007}. Four of genome
+annotation centers (such as, \textit{NCBI\cite{Sayers01012011},
+Dogma \cite{RDogma}, cpBase \cite{de2002comparative},
+CpGAVAS \cite{liu2012cpgavas}, and CEGMA\cite{parra2007cegma}})
+present various types of annotation tools (\emph{i.e.} cost-effective
+sequencing methods\cite{Bakke2009}) on different annotation
+levels. Generally, previous studies used one of three methods for gene
+finding in annotated genome using these
+centers: \textit{alignment-based, composition based, or combination of
+both\cite{parra2007cegma}}. The alignment-based method is used when we
+try to predict a coding gene (\emph{i.e.}. genes that produce
+proteins) by aligning DNA sequence of gene to the protein of cDNA
+sequence of homology\cite{parra2007cegma}. This approach also is used
+in GeneWise\cite{birney2004genewise}. Composition-based method (known
+as \textit{ab initio}) is based on a probabilistic model of gene
+structure to find genes according to the gene value probability
+(GeneID\cite{parra2000geneid}). In this section, we consider a new
+method of finding core genes from large amount of chloroplast genomes,
+as a solution of the problem resulting from the method stated in
+section two. This method is based on extracting gene features. A
+general overview of the system is illustrated in Figure \ref{Fig1}.\\
