Can A Duplication Mutation Be Beneficial?

Pim van Meurs (entheta@eskimo.com)
Sat, 11 Sep 1999 12:15:09 -0700

Can A Duplication Mutation Be Beneficial?

Yes. For example:

"A mosquito species called Culex pipiens can now survive massive doses of organophosphate insecticides. The mosquitoes actually digest the poison, using a suite of enzymes known as esterases. The genes that make these esterases are known as alleles B1 and B2. Many strains of Culex pipiens now carry as many as 250 copies of the B1 allele and 60 copies of B2."

The Beak of the Finch p.254

The mosquitoes acquired B1 and B2 by two mutations. They then acquired the huge number of copies by duplication mutations. They benefit because the extra copies cause their bodies to produce extra esterase. Whenever a huge amount of insecticide is sprayed, mosquitoes that have lots of
resistance are the most likely to live and reproduce.

Until 1984, California mosquitoes had neither B1 nor B2. They acquired all those copies in a single decade.