Neo-sex Chromosomes in the Monarch Butterfly, Danaus plexippus
Mongue AJ, Nguyen P, Voleníková A and others. G3 (Bethesda, Md.), October 2017.
Read the paper Free to read · doi:10.1534/g3.117.300187
What this paper is about
A neo-sex chromosome is an ordinary chromosome that has fused to a sex chromosome. The authors found one in the monarch and in several close relatives, by comparing sequencing depth between males and females.
Most of the monarch genome assembly was also assigned to chromosomes for the first time, by matching genes against butterflies with mapped genomes.
Summarised here from the abstract below. Not the authors’ words.
Abstract
We report the discovery of a neo-sex chromosome in the monarch butterfly, Danaus plexippus, and several of its close relatives. Z-linked scaffolds in the D. plexippus genome assembly were identified via sex-specific differences in Illumina sequencing coverage. Additionally, a majority of the D. plexippus genome assembly was assigned to chromosomes based on counts of one-to-one orthologs relative to the butterfly Melitaea cinxia (with replication using two other lepidopteran species), in which genome scaffolds have been mapped to linkage groups. Sequencing coverage-based assessments of Z linkage combined with homology-based chromosomal assignments provided strong evidence for a Z-autosome fusion in the Danaus lineage, involving the autosome homologous to chromosome 21 in M. cinxia Coverage analysis also identified three notable assembly errors resulting in chimeric Z-autosome scaffolds. Cytogenetic analysis further revealed a large W chromosome that is partially euchromatic, consistent with being a neo-W chromosome. The discovery of a neo-Z and the provisional assignment of chromosome linkage for >90% of D. plexippus genes lays the foundation for novel insights concerning sex chromosome evolution in this female-heterogametic model species for functional and evolutionary genomics.
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title = {Neo-sex Chromosomes in the Monarch Butterfly, Danaus plexippus (listing)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/research/neo-sex-chromosomes-in-the-monarch-butterfly-danaus-plexippus-2017/},
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