What does MT,GL000207 mean?

Question

[bluemonster0808]

I know human have 1~22 + X/Y chromosomes.

But I find MT, GL000207,GL000203 etc in human_g1k_v37_decoy.breakpoints.bed.

What are these chromosomes?

Answer 1

[e.rempel]

MT could be mitochondria, others are non canonical chromosomes