Pan-genome is a generic term for all genes of a species, which is distinct from the genes of individual genomes. The genome of an individual is representative of the genome of the species.
  The analysis of a genome as a template does not provide a complete picture of the genetic information of a species at the gene level, especially when studying different subspecies or variants of the same species, where the differences in such unique segments are often more important than the differences in shared segments. The analysis of core and non-core genes is fundamental to the study of within-species variation from the perspective of unique gene sequences.

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