Quantitative analysis of black blotching in a crossbred red tilapia and its effects on performance traits via a path analysis methodology

Lago, Aline de Assis; Neto, Rafael Vilhena Reis; Rezende, Tiago Teruel; Ribeiro, Mayra Cristina da Silva; Freitas, Rilke Tadeu Fonseca de; Hilsdorf, Alexandre Wagner Silva

doi:10.1007/s13353-019-00513-y

Cited by 9 publications

(9 citation statements)

References 26 publications

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“…16 In addition, our slc45a2 mutant tilapia does not express melanin in its eyes or have black blotched skin, which characterize the currently known red tilapia strains. 2,3,6,16 These data suggest that current tilapia strains of red phenotypes do not result from perturbation in the slc45a2 gene or protein. Furthermore, previously identified strains of Mozambique ''gold'' 45 or Nile ''blond'' and ''syrup'' 46 tilapias, as well as hybrid strains, all suffer from various levels of WT coloration or blotched progenies, which resulted from impaired melanophore development.…”

Section: Discussionmentioning

confidence: 76%

“…However, currently available strains exhibit black and dark-red blotching that reduce their market value, and their unclear genetic background impairs breeding and culture practices. 2,3,44 Impairments in SLC45A2 in humans lead to OCA, 12 which is also phenocopied in other vertebrates, including fish. 9,15 Additionally, it was previously suggested that red tilapia phenotypes result from dermal blood irrigation within a melanophore-perturbed skin.…”

Section: Discussionmentioning

confidence: 99%

“…1 In recent years, red tilapias, which are usually different hybrid strains of Nile tilapia crossed with Mozambique, blue, and Zanzibar tilapias (O. mossambicus, O. aureus, O. hornorum), have been gaining worldwide popularity, and their prices have increased accordingly. 2,3 The market price of red tilapia in the Philippines is double that of gray-colored wild-type (WT) tilapia, and for similar reasons, 85% of the tilapias grown in Malaysia are red tilapia strains. 4,5 It has been suggested that the red coloration is due to faulty melanophore development.…”

Section: Introductionmentioning

confidence: 99%

“…6 Nonetheless, red to albino-like tilapia strains display black eye pigmentation that is usually accompanied by a variable rate and pattern of black blotching. 2,3,6,16 In contrast, naturally occurring loss-offunction mutations in the slc45a2 gene resulted in complete and heritable albinism in medaka 9 and zebrafish, 15 which was transiently phenocopied in Atlantic salmon (Salmo salar) 17 and marine medaka (Oryzias melastigma). 18 Thus, the currently available strains of red tilapia are less likely to have resulted from a naturally occurring null mutation in the slc45a2 gene.…”

Section: Introductionmentioning

confidence: 99%

“…27,28 Current data suggest that although red tilapia strains are available, their color phenotypes are not uniform, and the regulating genes remain largely unknown. 2,3,16 This emphasizes the need for a tilapia strain with an inheritable uniform red color that is stable throughout life and which is established on a clear genetic background that would allow tractability of its inheritance under various breeding and genetic selection protocols. In the present work, we describe the identification of slc45a2 in Nile tilapia and utilization of CRISPR ribonucleoproteins (RNPs) for induction of somatic and germline indels in the tilapia slc45a2 exon 1.…”

Section: Introductionmentioning

confidence: 99%

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Genome Editing Using the CRISPR-Cas9 System to Generate a Solid-Red Germline of Nile Tilapia (Oreochromis niloticus)

et al. 2021

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In recent years, there has been increasing demand for red tilapia, which are commercial strains of hybrids of different tilapiine species or red variants of highly inbred Nile tilapia. However, red tilapia phenotypes are genetically unstable and affected by environmental factors, resulting in nonuniform coloration with black or dark-red color blotches that reduce their market value. Solute carrier family 45 member 2 (SLC45A2) is a membrane transporter that mediates melanin biosynthesis and is evolutionarily conserved from fish to humans. In the present study, we describe the generation of a stable and heritable red tilapia phenotype by inducing loss-of-function mutations in the slc45a2 gene. For this purpose, we identified the slc45a2 gene in Nile tilapia and designed highly specific guide RNAs (gRNA) for its genomic sequence. Multiplex microinjection of slc45a2-specific ribonucleoproteins to Nile tilapia zygotes induced up to 97-99% albinism, including loss of melanin in the eye. Next-generation sequencing of the injected zygotes demonstrated that all injected fish carried mutant alleles with variable mutagenesis efficiencies. Sanger sequencing of the genomic target region in the slc45a2 gene from fin clips, sperm, and F 1 offspring of a highly mutant male identified various genomic indels and germline transmission of the sperm-identified indels. Overall, this work demonstrates the generation of somatic and germline slc45a2 mutant alleles, which leads to complete albinism in Nile tilapia.

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