A key transcription cofactor on the nascent sex chromosomes of European tree frogs (Hyla arborea).
We show that MED15, a key component of the transcription complex Mediator, lies within the nonrecombining segment of nascent sex chromosomes in the male-heterogametic Hyla arborea. Both X and Y alleles are expressed during embryonic development and differ by three frame-preserving indels (eight amino acids in total) within their glutamine-rich central part. These changes have the potential to affect the conformation of the Mediator complex and to activate genes in a sex-specific way and might thus represent the first steps toward the acquisition of a male-specific function. Alternatively, they might result from an ancestral neutral polymorphism, with different alleles picked by chance on the X and Y chromosomes when MED15 was trapped in the nonrecombining segment.
Niculita-Hirzel
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Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland.
Stöck
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Perrin
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N
D000483:Alleles; D000818:Animals; D017124:Conserved Sequence; D005060:Europe; D008297:Male; D011898:Ranidae / Q000235:genetics*; D012730:Sex Chromosomes / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*
D014157:Transcription Factors