February 2020

Neo-sex chromosomes are found in many taxa, but the forces driving their emergence and spread are poorly understood. The female-specific neo-W chromosome of the African monarch (or queen) butterfly Danaus chrysippus presents an intriguing case study because it is restricted to a single ‘contact zone’ population, involves a putative colour patterning supergene, and co-occurs with infection by the male-killing endosymbiont Spiroplasma. This study by Martin et al. investigates the origin and evolution of this system using whole genome sequencing. They identify the ‘BC supergene’, a broad region of suppressed recombination across nearly half a chromosome, which links two colour patterning loci that control the forewing colour pattern differences between D. chrysippus subspecies. They then show that the same chromosome has recently formed a neo-W that has spread through the contact zone within approximately 2,200 years. Analysis of the genome of the male-killing Spiroplasma reveals perfect genealogical congruence with the neo-W, suggesting that the neo-W has hitchhiked to high frequency as the male-killer has spread through the population. Overall. the findings show how hitchhiking can occur between the physically unlinked genomes of host and endosymbiont, with dramatic consequences. The image shows a female D. chrysippus drinking nectar from a Calotropis milkweed flower. She will also lay her eggs on this plant species, and the caterpillars who feed on it will carry its toxic cardenolide glycosides; the butterfly’s bright orange, black and white patterns warn predators that it is distasteful.

Image Credit: Chris Ward

Unsolved Mystery

The unidentified hormonal defense against weight gain

Jens Lund, Camilla Lund, Thomas Morville, Christoffer Clemmensen

PLOS Biology: published February 25, 2020 | https://doi.org/10.1371/journal.pbio.3000629

Perspective

Macroalgal germplasm banking for conservation, food security, and industry

Rachael Wade, Simona Augyte, Maddelyn Harden, Sergey Nuzhdin, Charles Yarish, Filipe Alberto

PLOS Biology: published February 14, 2020 | https://doi.org/10.1371/journal.pbio.3000641

Community Page

Improving the trustworthiness, usefulness, and ethics of biomedical research through an innovative and comprehensive institutional initiative

Daniel Strech, Tracey Weissgerber, Ulrich Dirnagl, on behalf of QUEST Group

PLOS Biology: published February 11, 2020 | https://doi.org/10.1371/journal.pbio.3000576

Research Articles

Selective sweeps on novel and introgressed variation shape mimicry loci in a butterfly adaptive radiation

Markus Moest, Steven M. Van Belleghem, Jennifer E. James, Camilo Salazar, Simon H. Martin, Sarah L. Barker, Gilson R. P. Moreira, Claire Mérot, Mathieu Joron, Nicola J. Nadeau, Florian M. Steiner, Chris D. Jiggins

PLOS Biology: published February 6, 2020 | https://doi.org/10.1371/journal.pbio.3000597

Combining genomics and epidemiology to track mumps virus transmission in the United States

Shirlee Wohl, Hayden C. Metsky, Stephen F. Schaffner, Anne Piantadosi, Meagan Burns, Joseph A. Lewnard, Bridget Chak, Lydia A. Krasilnikova, Katherine J. Siddle, Christian B. Matranga, Bettina Bankamp, Scott Hennigan, Brandon Sabina, Elizabeth H. Byrne, Rebecca J. McNall, Rickey R. Shah, James Qu, Daniel J. Park, Soheyla Gharib, Susan Fitzgerald, Paul Barreira, Stephen Fleming, Susan Lett, Paul A. Rota, Lawrence C. Madoff, Nathan L. Yozwiak, Bronwyn L. MacInnis, Sandra Smole, Yonatan H. Grad, Pardis C. Sabeti

PLOS Biology: published February 11, 2020 | https://doi.org/10.1371/journal.pbio.3000611

Time of day is associated with paradoxical reductions in global signal fluctuation and functional connectivity

Csaba Orban, Ru Kong, Jingwei Li, Michael W. L. Chee, B. T. Thomas Yeo

PLOS Biology: published February 18, 2020 | https://doi.org/10.1371/journal.pbio.3000602

Organization of primate amygdalar–thalamic pathways for emotions

Clare Timbie, Miguel Á. García-Cabezas, Basilis Zikopoulos, Helen Barbas

PLOS Biology: published February 27, 2020 | https://doi.org/10.1371/journal.pbio.3000639

A wake-active locomotion circuit depolarizes a sleep-active neuron to switch on sleep

Elisabeth Maluck, Inka Busack, Judith Besseling, Florentin Masurat, Michal Turek, Karl Emanuel Busch, Henrik Bringmann

PLOS Biology: published February 20, 2020 | https://doi.org/10.1371/journal.pbio.3000361

Lack of the MHC class II chaperone H2-O causes susceptibility to autoimmune diseases

Robin A. Welsh, Nianbin Song, Catherine A. Foss, Tatiana Boronina, Robert N. Cole, Scheherazade Sadegh-Nasseri

PLOS Biology: published February 18, 2020 | https://doi.org/10.1371/journal.pbio.3000590

Cell-autonomous light sensitivity via Opsin3 regulates fuel utilization in brown adipocytes

Mari Sato, Tadataka Tsuji, Kunyan Yang, Xiaozhi Ren, Jonathan M. Dreyfuss, Tian Lian Huang, Chih-Hao Wang, Farnaz Shamsi, Luiz O. Leiria, Matthew D. Lynes, King-Wai Yau, Yu-Hua Tseng

PLOS Biology: published February 10, 2020 | https://doi.org/10.1371/journal.pbio.3000630

Snail synchronizes endocycling in a TOR-dependent manner to coordinate entry and escape from endoreplication pausing during the Drosophila critical weight checkpoint

Jie Zeng, Nhan Huynh, Brian Phelps, Kirst King-Jones

PLOS Biology: published February 25, 2020 | https://doi.org/10.1371/journal.pbio.3000609

Pancreatic β cell microRNA-26a alleviates type 2 diabetes by improving peripheral insulin sensitivity and preserving β cell function

Haixia Xu, Xiao Du, Jia Xu, Yu Zhang, Yan Tian, Geng Liu, Xiuxuan Wang, Meilin Ma, Wenya Du, Yu Liu, Lunzhi Dai, Wendong Huang, Nanwei Tong, Yuquan Wei, Xianghui Fu

PLOS Biology: published February 24, 2020 | https://doi.org/10.1371/journal.pbio.3000603

NRF2 negatively regulates primary ciliogenesis and hedgehog signaling

Pengfei Liu, Matthew Dodson, Deyu Fang, Eli Chapman, Donna D. Zhang

PLOS Biology: published February 13, 2020 | https://doi.org/10.1371/journal.pbio.3000620

Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca²⁺, and receptor binding

Dibyendu Kumar Das, Uriel Bulow, William E. Diehl, Natasha D. Durham, Fernando Senjobe, Kartik Chandran, Jeremy Luban, James B. Munro

PLOS Biology: published February 10, 2020 | https://doi.org/10.1371/journal.pbio.3000626

Functional interactions between posttranslationally modified amino acids of methyl-coenzyme M reductase in Methanosarcina acetivorans

Dipti D. Nayak, Andi Liu, Neha Agrawal, Roy Rodriguez-Carerro, Shi-Hui Dong, Douglas A. Mitchell, Satish K. Nair, William W. Metcalf

PLOS Biology: published February 24, 2020 | https://doi.org/10.1371/journal.pbio.3000507

Cover

Whole-chromosome hitchhiking driven by a male-killing endosymbiont