TY - JOUR

T1 - Oca2 targeting using CRISPR/Cas9 in the Malawi cichlid Astatotilapia calliptera

AU - Clark, Bethan

AU - Elkin, Joel

AU - Marconi, Aleksandra

AU - Turner, George F.

AU - Smith, Alan M.

AU - Joyce, Domino

AU - Miska, Eric A.

AU - Juntti, Scott A.

AU - Santos, M. Emília

PY - 2022/4

Y1 - 2022/4

N2 - Identifying genetic loci underlying trait variation provides insights into the mechanisms of diversification, but demonstrating causality and characterizing the role of genetic loci requires testing candidate gene function, often in non-model species. Here we establish CRISPR/Cas9 editing in Astatotilapia calliptera, a generalist cichlid of the remarkably diverse Lake Malawi radiation. By targeting the gene oca2 required for melanin synthesis in other vertebrate species, we show efficient editing and germline transmission. Gene edits include indels in the coding region, probably a result of non-homologous end joining, and a large deletion in the 3′ untranslated region due to homology-directed repair. We find that oca2 knock-out A. calliptera lack melanin, which may be useful for developmental imaging in embryos and studying colour pattern formation in adults. As A. calliptera resembles the presumed generalist ancestor of the Lake Malawi cichlid radiation, establishing genome editing in this species will facilitate investigating speciation, adaptation and trait diversification in this textbook radiation.

AB - Identifying genetic loci underlying trait variation provides insights into the mechanisms of diversification, but demonstrating causality and characterizing the role of genetic loci requires testing candidate gene function, often in non-model species. Here we establish CRISPR/Cas9 editing in Astatotilapia calliptera, a generalist cichlid of the remarkably diverse Lake Malawi radiation. By targeting the gene oca2 required for melanin synthesis in other vertebrate species, we show efficient editing and germline transmission. Gene edits include indels in the coding region, probably a result of non-homologous end joining, and a large deletion in the 3′ untranslated region due to homology-directed repair. We find that oca2 knock-out A. calliptera lack melanin, which may be useful for developmental imaging in embryos and studying colour pattern formation in adults. As A. calliptera resembles the presumed generalist ancestor of the Lake Malawi cichlid radiation, establishing genome editing in this species will facilitate investigating speciation, adaptation and trait diversification in this textbook radiation.

KW - Organismal and evolutionary biology

KW - Research articles

KW - cichlids

KW - CRISPR/Cas9

KW - adaptive radiation

KW - functional genetics

KW - evo-devo

U2 - 10.1098/rsos.220077

DO - 10.1098/rsos.220077

M3 - Article

VL - 9

JO - Royal Society Open Science

JF - Royal Society Open Science

SN - 2054-5703

IS - 4

M1 - 220077

ER -