Bardil, A. | bioRxiv Science

bioRxiv2026

The genome of the avian malaria parasite Haemoproteus majoris (lineage WW2) and its relationship to other Plasmodium species

Avian malaria parasites form a highly prevalent and genetically diverse group within the haemosporidians, yet they have long been overlooked relative to their human- and rodent-infecting counterparts. Among these, parasites of the genus Haemoproteus (Haemosporida, Haemoproteidae) are widespread and prevalent blood parasites of birds, transmitted by louse flies (Hippoboscidae) and biting midges (Ceratopogonidae). Recent phylogenomic analyses place Haemoproteus parasites at the root of the haemosporidian tree, making genomic data from these taxa essential for understanding the evolutionary origins of malaria parasites. To date, only two avian Plasmodium and one avian Haemoproteus genomes have been sequenced. We present the first assembled genome of Haemoproteus majoris (lineage WW2), a common blood parasite of passerine birds. As avian erythrocytes are nucleated, parasite DNA was enriched by FACS-based sorting to discriminate and isolate the parasite from host cell nuclei prior to whole-genome amplification. The genome was assembled using Nanopore long-read sequencing and polished with Illumina short-reads, yielding 145 contigs with a total assembly size of 23.9Mb and a G+C content of 27.85%. Genome annotation identified 5501 protein-coding genes, 69 non-coding RNA genes, and 57 long terminal repeat retrotransposons (LRT-RTs), including one full-length element. This genomic resource represents a critical step towards elucidating the evolutionary history and genomic architecture of avian malaria parasites. SIGNIFICANCE STATEMENTWe present the first assembled genome of Haemoproteus majoris (lineage WW2), a prevalent and generalist avian malaria parasite. Taxonomic resolution of this genus is difficult as there are few distinct morphological differences among closely-related species. This genome provides a valuable resource for studying the evolution within the Haemoproteus genus and to elucidate the evolutionary history of malaria parasites.

genomics↗

bioRxiv2020

The replicative amplification of MITEs and their impact on rice trait variability

Transposable elements (TEs) are a rich source of genetic variability. Among TEs, Miniature Inverted- repeat Transposable Elements (MITEs) are of particular interest as they are present in high copy numbers in plant genomes and are closely associated with genes. MITEs are deletion derivatives of class II transposons, and can be mobilized by the transposases encoded by the latters through a typical cut-and-paste mechanism. However, this mechanism cannot account for the high copy number MITEs attain in plant genomes, and the mechanism by which MITEs amplify remains elusive. We present here an analysis of 103,109 Transposon Insertion Polymorphisms (TIPs) in 1,059 O. sativa genomes representing the main rice population groups. We show that an important fraction of MITE insertions has been fixed in rice concomitantly with rice domestication. However, another fraction of MITE insertions is present at low frequencies. We performed MITE TIP-GWAS to study the impact of these elements on agronomically important traits and found that these elements uncover more trait associations than SNPs on important phenotypes such as grain width. Finally, using SNP-GWAS and TIP-GWAS we provide evidences of the replicative amplification of MITEs, suggesting a mechanism of amplification uncoupled from the typical cut-and-paste mechanism of class II transposons.

molecular biology↗