why reads piled up at the repeat regions?

[qiudao]

Hi,

I just take a look at some ChIP-seq data. I found the the reads piled up at the repeat region. could anyone explain this phenomena to me? Thanks.

[olus]

Hello.
I've noticed the same phenomen in a mouse Chip-Seq: reads piled up in near centromeric regions.
I'm wondering if is something related to the 'aligment phase' or is it a bias for low complexity regions?
At the moment I've assumed is an artefact due to alignment, but I'll dig on it further.

Cheers