Understanding mitochondrial genome fragmentation in parasitic lice (Insecta: Phthiraptera)

Paper written in Chinese, Title: 虱 目裂 化 线 粒 体 基 因组 研 究 进 展

Abstract: Lice are obligateectoparasites of mammals and birds. Extensiver fagmentation of mitochondrial genomes has been found in some louse  species in the families Pediculidae,Pthiridae,Philopteridae and Trichodectidae. For example, the mt genomes of human body louse ( Pediculus humanus), head louse (Pediculus humanus capitis), and pubic louse (Pthirus pubis) have 20, 20 and 14 mini-chromosomes,respectively.These mini-chromosomes might be the results of deletion and recombination of mt genes .The factors and mechanism s of mitochondrial genome fragmentation are currently unknown. The fragmentation might be the results of evolutionary selection or random genetic drift or it is probably related to the lack of mtSSB (mitochondrial single-strand DNA binding protein).Understanding the fragmentation of mitochondrial genomes is  of significance for understanding the origin and evolution of mitochondria. This paper reviews the recent advances in the studies of mitochondrial genome fragmentation in lice, including the phenomena of mitochrondrial genome fragmentation, characteristics of fragmentated mitochondrial genomes, and some factors and mechanism possibly leading to the mitochondrial genome fragmentation of lice.Perspectives for future studies on fragmented mt genomes arealso discussed.