NCBI36

NCBI36 refers to a specific version of the human genome reference sequence developed by the National Center for Biotechnology Information (NCBI). It is based on the assembly of the human genome known as *Homo sapiens* GRCh36, which was released in 2006. This reference sequence was derived from the initial draft of the Human Genome Project and later refined to provide a more accurate representation of the human genome.

NCBI36 is part of the broader NCBI Reference Sequence (RefSeq) database, which serves as a standardized framework for comparing genomic data across different studies. The assembly includes 23 chromosomes (22 autosomes plus the X and Y chromosomes) and incorporates updates to improve accuracy, such as corrections for sequencing errors and gaps in the original draft. It also includes mitochondrial DNA (GenBank accession number NC_012920) as a separate entry.

This reference was widely used in early genomic research, bioinformatics tools, and clinical applications before being superseded by newer versions like GRCh37 (hg19) and GRCh38 (hg38). NCBI36 remains relevant in legacy datasets, older publications, and certain bioinformatics pipelines that rely on its specific coordinate system. Researchers often need to align modern data to older references like NCBI36 when working with historical genomic studies or tools designed for that version.

The transition from NCBI36 to more recent references was driven by advancements in sequencing technology and the need for greater genomic resolution. While no longer the primary reference, NCBI36 continues to play a role in comparative genomics and historical genomic research.