Hsp70 genes of the Megaphragma amalphitanum (Hymenoptera: Trichogrammatidae) parasitic wasp

Abstract

Miniaturization is an evolutionary process that is widely represented in both invertebrates and vertebrates. Miniaturization frequently affects not only the size of the organism and its constituent cells, but also changes the genome structure and functioning. The structure of the main heat shock genes (hsp70 and hsp83) was studied in one of the smallest insects, the Megaphragma amalphitanum (Hymenoptera: Trichogrammatidae) parasitic wasp, which is comparable in size with unicellular organisms. An analysis of the sequenced genome has detected six genes that relate to the hsp70 family, some of which are apparently induced upon heat shock. Both induced and constitutively expressed hsp70 genes contain a large number of introns, which is not typical for the genes of this family. Moreover, none of the found genes form clusters, and they are all very heterogeneous (individual copies are only 75–85% identical), which indicates the absence of gene conversion, which provides the identity of genes of this family in Drosophila and other organisms. Two hsp83 genes, one of which contains an intron, have also been found in the M. amalphitanum genome.