A transposable element insertion is the switch between alternative life history strategies

Tradeoffs affect resource allocation during development and result in fitness consequences that drive the evolution of life history strategies. Yet despite their importance, we know little about the mechanisms underlying life history tradeoffs in wild populations. Many species of Colias butterflies exhibit an alternative life history strategy (ALHS) where females divert resources from wing pigment synthesis to reproductive and somatic development. Due to this reallocation, a wing color polymorphism is associated with the ALHS: individuals have either yellow/orange or white wings. Here we map the genetic basis of the ALHS switch in Colias crocea to a transposable element insertion downstream of the Colias homolog of BarH-1, a homeobox transcription factor. Using CRISPR/Cas9 gene editing, antibody staining, and electron microscopy we find morph-specific specific expression of BarH-1 suppresses the formation of pigment granules in wing scales. Lipid and transcriptome analyses reveal physiological differences associated with the ALHS. These findings characterize a novel mechanism for a female-limited ALHS and show that the switch arises via recruitment of a transcription factor previously known for its function in cell fate determination in pigment cells of the retina.

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A transposable element insertion is associated with an alternative life history strategy

Nature Communications ◽

10.1038/s41467-019-13596-2 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 9

Author(s):

Alyssa Woronik ◽

Kalle Tunström ◽

Michael W. Perry ◽

Ramprasad Neethiraj ◽

Constanti Stefanescu ◽

...

Keyword(s):

Life History ◽

Transposable Element ◽

Life History Strategy ◽

Life History Strategies ◽

Transposable Element Insertion ◽

Specific Expression ◽

Pigment Synthesis ◽

Somatic Development ◽

Element Insertion ◽

Antibody Staining

AbstractTradeoffs affect resource allocation during development and result in fitness consequences that drive the evolution of life history strategies. Yet despite their importance, we know little about the mechanisms underlying life history tradeoffs. Many species of Colias butterflies exhibit an alternative life history strategy (ALHS) where females divert resources from wing pigment synthesis to reproductive and somatic development. Due to this reallocation, a wing color polymorphism is associated with the ALHS: either yellow/orange or white. Here we map the locus associated with this ALHS in Colias crocea to a transposable element insertion located downstream of the Colias homolog of BarH-1, a homeobox transcription factor. Using CRISPR/Cas9 gene editing, antibody staining, and electron microscopy we find white-specific expression of BarH-1 suppresses the formation of pigment granules in wing scales and gives rise to white wing color. Lipid and transcriptome analyses reveal physiological differences associated with the ALHS. Together, these findings characterize a mechanism for a female-limited ALHS.

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Faculty Opinions recommendation of A transposable element insertion is associated with an alternative life history strategy.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.737095116.793573790 ◽

2020 ◽

Author(s):

Chris Jiggins

Keyword(s):

Life History ◽

Transposable Element ◽

Life History Strategy ◽

Transposable Element Insertion ◽

Element Insertion

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Peer Review #1 of "RelocaTE2: a high resolution transposable element insertion site mapping tool for population resequencing (v0.1)"

10.7287/peerj.2942v0.1/reviews/1 ◽

2017 ◽

Keyword(s):

High Resolution ◽

Transposable Element ◽

Peer Review ◽

Insertion Site ◽

Transposable Element Insertion ◽

Element Insertion ◽

Mapping Tool ◽

Site Mapping

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nacre encodes a zebrafish microphthalmia-related protein that regulates neural-crest-derived pigment cell fate

Development ◽

10.1242/dev.126.17.3757 ◽

1999 ◽

Vol 126 (17) ◽

pp. 3757-3767 ◽

Cited By ~ 40

Author(s):

J.A. Lister ◽

C.P. Robertson ◽

T. Lepage ◽

S.L. Johnson ◽

D.W. Raible

Keyword(s):

Transcription Factor ◽

Retinal Pigment Epithelium ◽

Neural Crest ◽

Cell Fate ◽

Pigment Cell ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Pigment Cells ◽

Evolutionary Divergence ◽

Wild Type

We report the isolation and identification of a new mutation affecting pigment cell fate in the zebrafish neural crest. Homozygous nacre (nac(w2)) mutants lack melanophores throughout development but have increased numbers of iridophores. The non-crest-derived retinal pigment epithelium is normal, suggesting that the mutation does not affect pigment synthesis per se. Expression of early melanoblast markers is absent in nacre mutants and transplant experiments suggested a cell-autonomous function in melanophores. We show that nac(w2) is a mutation in a zebrafish gene encoding a basic helix-loop-helix/leucine zipper transcription factor related to microphthalmia (Mitf), a gene known to be required for development of eye and crest pigment cells in the mouse. Transient expression of the wild-type nacre gene restored melanophore development in nacre(−/−) embryos. Furthermore, misexpression of nacre induced the formation of ectopic melanized cells and caused defects in eye development in wild-type and mutant embryos. These results demonstrate that melanophore development in fish and mammals shares a dependence on the nacre/Mitf transcription factor, but that proper development of the retinal pigment epithelium in the fish is not nacre-dependent, suggesting an evolutionary divergence in the function of this gene.

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