1	1	chromosome	NCBI33	1	default_version
2	1	supercontig	\N	2	default_version
3	1	clone	\N	3	default_version
4	1	contig	\N	4	default_version,sequence_level
6	1	chunk	\N	5	default_version
7	1	alt_chrom	\N	6	default_version