Significance of gene amplification
There are two well-known cases where gene amplification is essential:
Sometimes cells need to produce large amounts of proteins, such as after cell division, when they need to grow. This means the cell needs lots of ribosomes.
The genome contains many copies of the genes coding for rRNA. These genes are expressed to ensure that enough ribosomes are present to produce all of the proteins that the cell needs.
HistonesWhenever a cell divides a large number of histones need to be produced in order to package the newly replicated DNA.
In these cases, simply increasing the rate of transcription is not enough. Instead, many copies of identical genes are present on the genome and all these copies are transcribed simultaneously. This produces vast amounts of the gene product.