Specific downregulation of spermatogenesis genes targeted by 22G RNAs in hybrid sterile males associated with an X-Chromosome introgression.
File(s)Genome Res.-2016-Li-gr.204479.116.pdf (3.33 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
Hybrid incompatibility (HI) prevents gene flow between species, thus lying at the heart of speciation genetics. One of the most common HIs is male sterility. Two superficially contradictory observations exist for hybrid male sterility. First, an introgression on the X chromosome is more likely to produce male sterility than on autosome (so-called large-X theory); second, spermatogenesis genes are enriched on the autosomes but depleted on the X chromosome (demasculization of X chromosome). Analysis of gene expression in Drosophila hybrids suggests a genetic interaction between X chromosome and autosomes that is essential for male fertility. However, the prevalence of such an interaction and its underlying mechanism remain largely unknown. Here we examine the interaction in nematode species by contrasting the expression of both coding genes and transposable elements (TEs) between hybrid sterile males and its parental nematode males. We use two lines of hybrid sterile males each carrying an independent introgression fragment from C. briggsae X chromosome in an otherwise C. nigoni background, which demonstrate similar defects in spermatogenesis. We observe a similar pattern of downregulated genes that are specific for spermatogenesis between the two hybrids. Importantly, the downregulated genes caused by the X chromosome introgressions show a significant enrichment on the autosomes, supporting an epistatic interaction between the X chromosome and autosomes. We investigate the underlying mechanism of the interaction by measuring small RNAs and find a subset of 22G RNAs specifically targeting the downregulated spermatogenesis genes are significantly upregulated in hybrids, suggesting that perturbation of small RNA-mediated regulation may contribute to the X-autosome interaction.
Date Issued
2016-05-18
Date Acceptance
2016-05-16
Citation
Genome Research, 2016, 26, pp.1219-1232
ISSN
1549-5469
Publisher
Cold Spring Harbor Laboratory Press
Start Page
1219
End Page
1232
Journal / Book Title
Genome Research
Volume
26
Copyright Statement
This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first six months after the full-issue publication date (see http://genome.cshlp.org/site/misc/terms.xhtml). After six months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.
Identifier
PII: gr.204479.116
Subjects
Bioinformatics
06 Biological Sciences
11 Medical And Health Sciences
Publication Status
Published