Subterranean Fishes of the World

4134

2018

Developmental Biology

311-312

441

Addendum to https://doi.org/10.1016/j.ydbio.2018.07.016

Afterthearticlewasinpress, five new fish werecollectedand sequencedfromCuevaSilvario(Fig. 6C andD)andCuevaUctuIji Changa (Fig. 6B, E-F),whicharebothinthesamekarsticareaas Jumandi Cave.Oneofthespecimens(Fig. 6B) istroglomorphic, depigmented, andsmalleyed,asistheJumandicavefish. Theother four specimens(Fig. 6C-F), despitesomevariabilityincoloration, havehigherlevelsofpigmentationthanthetroglomorphic fish and haveeyesthatappearnormalwithdistinctpupils(Fig. 6). Their generalappearanceisconsistentwithsurface fish thatmay haveenteredthecaves. Their 16Ssequenceshowedthattheanalyzed Astroblepus derivedfromtwoseparatelineages,onemadeupofthetroglo- morphic specimensandanotheroftheepigeomorphic fish. The troglomorphicspecimen(Fig. 6B) fromUctuIjiChangaCavedif- fered fromthetroglomorphicspecimenfromJumandi(Fig. 6A) by 7 of574bp(1.2%).Theepigeomorphic fish frombothcaveseither had identicalsequences,ordiffered(specimenC)byonlyonebp (0.17%).Thetroglomorphic fish differedfromtheepigeomorphic by 15–17bp(2.6–2.9%), suggestingthattheybelongtoeitherdis- tantly relatedpopulationsortosisterspecies. Mc1r sequencescorroboratedthepredictionthatpigmentedor surface Astroblepus would havetheG102(GGC;Gly)ofthenor- mally pigmentedvertebrates,whilethedepigmented,troglo- morphic Astroblepus wouldhavetheAGC(Ser)sequence.Allfour epigeomorphic Astroblepus had theGGCsequencesharedwith manypigmentedvertebrateswhilethenewtroglomorphic fish has theAGCallele,whichwasdescribedinthedepigmented Astroblepus from Jumandicave.Thisnewtroglomorphicspecimen may actuallybeheterozygousfortheMc1r,asevidencedbythe possible doubleA(green)/G(black)humpsinthechromatogram (Fig. 6B). SinceUctuIjiChangacaveisinhabitedbybothtroglo- morphic andsurfacelooking Astroblepus, finding anheterozygous individualmaysuggestthatsomelevelofintrogressionoccursin this cave. Resultsbeforethisaddendumshowedthatatroglomorphic A. pholeter displayedmutationsinultra-conservedareasofthepig- ment-controllinggene,whencomparedagainstothervertebrates. By sequencingtheMc1rgeneinspecimensfromboththepig- mented andthetroglomorphicmorphsof Astroblepus, thisad- dendum showsadirectcorrelationbetweenthepresenceofthis mutation andpigmentationlevelswithin Astroblepus. Thissug- geststhatthisparticularmutationoftheMc1risresponsiblefor the phenotypicexpressionofpigmentinthetroglomorphic fish, mimickingtheresultsof Astyanax. Itisthuscorroboratedthat Mc1r hasbeenthetargetofcavernicoleregressiveevolutionacross species indifferentfamiliesof fish.

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