What does the 'Genomic Gain' mean?

Question

[hamza.bakkali]

Hi,,

What does the 'Genomic Gain' mean?, I found it in a blog, the person who write it interprets the rise of the CNV segment mean by a genomic gain.

[ATpoint]

Linking to that blog would help to understand the context.

Answer 1

[Kevin Blighe]

A genomic gain is an amplification of a section of DNA. It is usually used in the context of cancer where a tumour exhibits copy number gain or loss at different loci when compared to a normal/healthy sample. Both of these terms, in this context, are referred to as copy number alterations (CNAs).

The term copy number variant (CNV) is used in a non-disease context where, for example, each individual exhibits natural variation on both SNPs and also CNVs. A CNV is generally considered a copy number amplification or loss > 1,000bp. Shorter ones are referred to as insertions or deletions (indels).

Of course, these rules are not rigid and you'll find many people referring to CNV in tumours and also short CNV of a few hundred bp.