Why a single gene can have multiple locations in chromosome?

Question

[Chen Sun]

In the genbank format data of gene annotation, usually I can find genes with location like this:

[42764:>153205](-)

It means that the gene start from 42764 and end in 153205 or further.

Why gene location can not be precisely reported?

Also, if I check this gene ("ABR") in UCSC, it will give a lot of gene locations, even in the same chromosome! (see: http://goo.gl/3er7BR)

These locations differs from each other, why could a gene have multi location, even in the same chromosome?

Answer 1

[Chris Miller]

You need to read up on the concept of genes that have alternative splicing or multiple isoforms. Once such mechanism uses different promoters/start sites for the same gene.