Phototransduction and clock gene expression in the troglobiont beetle Ptomaphagus hirtus of Mammoth cave

Friedrich, Markus (author), Chen, Rui (author), Daines, Bryce (author), Bao, Riyue (author), Caravas, Jason (author), Rai, Puneet K. (author), Zagmajster, Maja (author), Peck, Stewart B. (author)

Obligatory cave species exhibit dramatic trait modifications such as eye reduction, loss of pigmentation and an increase in touch receptors. As molecular studies of cave adaptation have largely concentrated on vertebrate models, it is not yet possible to probe for genetic universalities underlying cave adaptation. We have therefore begun to study the strongly cave-adapted small carrion beetle Ptomaphagus hirtus. For over 100 years, this flightless signature inhabitant of Mammoth Cave, the worldćs largest known cave system, has been considered blind despite the presence of residual lens structures. Bydeep sequencing of the adult head transcriptome, we discovered the transcripts of all core members of the phototransduction protein machinery. Combined with the absence of transcripts of select structural photoreceptor and eye pigmentation genes, these data suggest a reduced but functional visualsystem in P. hirtus. This conclusion was corroborated by a negative phototactic response of P. hirtus in lightždark choice tests. We further detected the expression of the complete circadian clock gene network in P. hirtus, raising the possibility of a role of light sensation in the regulation of oscillating processes. We speculate that P. hirtus is representative of a large number of animal species with highly reduced but persisting visual capacities in the twilight zone of the subterranean realm. These can now be studied on a broad comparative scale given the efficiency of transcript discovery by next-generation sequencing.

• Language: English
• Keywords: biospeleology, cave adaptation, circadian clock, phototransduction, evolution
• Work type: Not categorized
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Year: 2011
• Number of pages: Str. 3532-3541
• Numbering: Vol. 214
• PID: 20.500.12556/RUL-37528
• UDC: 591
• ISSN on article: 0022-0949
• DOI: 10.1242/jeb.060368
• COBISS.SI-ID: 2449743
• Publication date in RUL: 10.07.2015

Record is a part of a journal

• Title: Journal of Experimental Biology
• Shortened title: J. Exp. Biol.
• Publisher: Cambridge University Press
• ISSN: 0022-0949
• COBISS.SI-ID: 4736266