Most animals have a conserved mitochondrial genome structure composed of a single chromosome. However, some organisms have their mitochondrial genes separated on several smaller circular or linear chromosomes. Highly fragmented circular chromosomes (“minicircles”) are especially prevalent in parasitic lice (Insecta: Phthiraptera), with 16 species known to have between nine and 20 mitochondrial minicircles per genome. All of these species belong to the same clade (mammalian lice), suggesting a single origin of drastic fragmentation. Nevertheless, other work indicates a lesser degree of fragmentation (2–3 chromosomes/genome) is present in some avian feather lice (Ischnocera: Philopteridae). In this study, we tested for minicircles in four species of the feather louse genus Columbicola (Philopteridae). Using whole genome shotgun sequence data, we applied three different bioinformatic approaches for assembling the Columbicola mitochondrial genome. We further confirmed these approaches by assembling the mitochondrial genome of Pediculus humanus from shotgun sequencing reads, a species known to have minicircles. Columbicola spp. genomes are highly fragmented into 15–17 minicircles between ∼1,100 and ∼3,100 bp in length, with 1–4 genes per minicircle. Subsequent annotation of the minicircles indicated that tRNA arrangements of minicircles varied substantially between species. These mitochondrial minicircles for species of Columbicola represent the first feather lice (Philopteridae)more »
This content will become publicly available on September 1, 2023
Genomic Approaches to Uncovering the Coevolutionary History of Parasitic Lice
Next-generation sequencing technologies are revolutionizing the fields of genomics, phylogenetics, and population genetics. These new genomic approaches have been extensively applied to a major group of parasites, the lice (Insecta: Phthiraptera) of birds and mammals. Two louse genomes have been assembled and annotated to date, and these have opened up new resources for the study of louse biology. Whole genome sequencing has been used to assemble large phylogenomic datasets for lice, incorporating sequences of thousands of genes. These datasets have provided highly supported trees at all taxonomic levels, ranging from relationships among the major groups of lice to those among closely related species. Such approaches have also been applied at the population scale in lice, revealing patterns of population subdivision and inbreeding. Finally, whole genome sequence datasets can also be used for additional study beyond that of the louse nuclear genome, such as in the study of mitochondrial genome fragmentation or endosymbiont function.
- Award ID(s):
- 1926919
- Publication Date:
- NSF-PAR ID:
- 10358287
- Journal Name:
- Life
- Volume:
- 12
- Issue:
- 9
- Page Range or eLocation-ID:
- 1442
- ISSN:
- 2075-1729
- Sponsoring Org:
- National Science Foundation
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