10.5061/DRYAD.8716
Walters, James R.
University of Cambridge
Hardcastle, Thomas J.
University of Cambridge
Data from: Getting a full dose? Reconsidering sex chromosome dosage
compensation in the silkworm, Bombyx mori
Dryad
dataset
2011
silkworm
Bombyx mori
Sex chromosomes
Dosage compensation
2011-03-02T19:10:58Z
2011-03-02T19:10:58Z
en
https://doi.org/10.1093/gbe/evr036
2976066 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Dosage compensation – equalizing gene expression levels in response to
differences in gene dose or copy number – is classically considered to
play a critical role in the evolution of heteromorphic sex chromosomes. As
the X and Y diverge through degradation and gene loss on the Y (or the W
in female-heterogametic ZW taxa), it is expected that dosage compensation
will evolve to correct for sex-specific differences in gene dose. While
this is observed in some organisms, recent genome-wide expression studies
in other taxa have revealed striking exceptions. In particular, reports
that both birds and the silkworm moth (Bombyx mori) lack dosage
compensation have spurred speculation that this is the rule for all
female-heterogametic taxa. Here we revisit the issue of dosage
compensation in silkworm by replicating and extending the previous
analysis. Contrary to previous reports, our efforts reveal that the global
male:female expression ratio does not differ between the Z and autosomes,
a pattern typically associated with dosage compensated taxa. We believe
the previous report of unequal male:female ratios on the Z reflects
artifacts of microarray normalization in conjunction with not testing a
major assumption that the male:female global expression ratio was unbiased
for autosomal loci. However, we also find that the global Z chromosome
expression is significantly reduced relative to autosomes, a pattern not
expected in dosage compensated taxa. This combination of male:female
parity with an overall reduction in expression for sex-linked loci is not
consistent with the prevailing evolutionary theory of sex chromosome
evolution and dosage compensation.
ML_threshold_indicatorProbes_listed_by_genes