Genome sequence of Ophryocystis elektroscirrha, an apicomplexan parasite of monarch butterflies: cryptic diversity and response to host-sequestered plant chemicals
Mongue AJ, Martin SH, Manweiler REV and others. BMC genomics, May 2023.
Read the paper Free to read · doi:10.1186/s12864-023-09350-0
What this paper is about
The genome of OE, the protozoan parasite that deforms monarch wings and shortens their lives. It is tiny: 9 million bases and under 3,000 genes, half what comparable parasites carry.
The sequencing also revealed cryptic diversity within what had been treated as one parasite, and allowed the authors to ask how it copes with the cardenolides its host has stored.
Summarised here from the abstract below. Not the authors’ words.
Abstract
Apicomplexa are ancient and diverse organisms which have been poorly characterized by modern genomics. To better understand the evolution and diversity of these single-celled eukaryotes, we sequenced the genome of Ophryocystis elektroscirrha, a parasite of monarch butterflies, Danaus plexippus. We contextualize our newly generated resources within apicomplexan genomics before answering longstanding questions specific to this host-parasite system. To start, the genome is miniscule, totaling only 9 million bases and containing fewer than 3,000 genes, half the gene content of two other sequenced invertebrate-infecting apicomplexans, Porospora gigantea and Gregarina niphandrodes. We found that O. elektroscirrha shares different orthologs with each sequenced relative, suggesting the true set of universally conserved apicomplexan genes is very small indeed. Next, we show that sequencing data from other potential host butterflies can be used to diagnose infection status as well as to study diversity of parasite sequences. We recovered a similarly sized parasite genome from another butterfly, Danaus chrysippus, that was highly diverged from the O. elektroscirrha reference, possibly representing a distinct species. Using these two new genomes, we investigated potential evolutionary response by parasites to toxic phytochemicals their hosts ingest and sequester. Monarch butterflies are well-known to tolerate toxic cardenolides thanks to changes in the sequence of their Type II ATPase sodium pumps. We show that Ophryocystis completely lacks Type II or Type 4 sodium pumps, and related proteins PMCA calcium pumps show extreme sequence divergence compared to other Apicomplexa, demonstrating new avenues of research opened by genome sequencing of non-model Apicomplexa.
Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.
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"Genome sequence of Ophryocystis elektroscirrha, an apicomplexan parasite of monarch butterflies: cryptic diversity and response to host-sequestered plant chemicals (listing)." Milkweed USA, 2026, https://milkweedusa.com/research/genome-sequence-of-ophryocystis-elektroscirrha-an-apicomplexan-parasite-of-2023/. Accessed DATE.
Milkweed USA. "Genome sequence of Ophryocystis elektroscirrha, an apicomplexan parasite of monarch butterflies: cryptic diversity and response to host-sequestered plant chemicals (listing)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/research/genome-sequence-of-ophryocystis-elektroscirrha-an-apicomplexan-parasite-of-2023/.
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title = {Genome sequence of Ophryocystis elektroscirrha, an apicomplexan parasite of monarch butterflies: cryptic diversity and response to host-sequestered plant chemicals (listing)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/research/genome-sequence-of-ophryocystis-elektroscirrha-an-apicomplexan-parasite-of-2023/},
note = {Accessed DATE}
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