Evolution of stickleback spines through independent cis-regulatory changes at HOXDB
Understanding the mechanisms leading to new traits or additional features in organisms is a fundamental goal of evolutionary biology. We show that HOXDB regulatory changes have been used repeatedly in different fish genera to alter the length and number of the prominent dorsal spines used to classif...
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Published in | Nature ecology & evolution Vol. 6; no. 10; pp. 1537 - 1552 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
01.10.2022
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | Understanding the mechanisms leading to new traits or additional features in organisms is a fundamental goal of evolutionary biology. We show that
HOXDB
regulatory changes have been used repeatedly in different fish genera to alter the length and number of the prominent dorsal spines used to classify stickleback species. In
Gasterosteus aculeatus
(typically ‘three-spine sticklebacks’), a variant
HOXDB
allele is genetically linked to shortening an existing spine and adding an additional spine. In
Apeltes quadracus
(typically ‘four-spine sticklebacks’), a variant
HOXDB
allele is associated with lengthening a spine and adding an additional spine in natural populations. The variant alleles alter the same non-coding enhancer region in the
HOXDB
locus but do so by diverse mechanisms, including single-nucleotide polymorphisms, deletions and transposable element insertions. The independent regulatory changes are linked to anterior expansion or contraction of
HOXDB
expression. We propose that associated changes in spine lengths and numbers are partial identity transformations in a repeating skeletal series that forms major defensive structures in fish. Our findings support the long-standing hypothesis that natural
Hox
gene variation underlies key patterning changes in wild populations and illustrate how different mutational mechanisms affecting the same region may produce opposite gene expression changes with similar phenotypic outcomes.
Differences in a non-coding enhancer region of the
HOXDB
locus underlie the differences between stickleback species in dorsal spine length and number. These differences include single-nucleotide polymorphisms, deletions and transposable element insertions. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2397-334X 2397-334X |
DOI: | 10.1038/s41559-022-01855-3 |