Red Coloration in an Anchialine Shrimp: Carotenoids, Genetic Variation, and Candidate Genes
Red Coloration in an Anchialine Shrimp: Carotenoids, Genetic Variation, and Candidate Genes
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DOI：
10.1086/708625
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发表时间：
2020-04-01
影响因子：
1.6
通讯作者：
Havird, Justin C.
中科院分区：
文献类型：
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作者：
Weaver, Ryan J.;Gonzalez, Bryson K.;Havird, Justin C.
红色是动物中广泛分布的表型，但这种表型的色素和遗传基础在相对较少的分类单元中得到描述。在这里，我们展示了夏威夷特有的 Anchialine 虾 Halocaridina rubra 由于虾青素的积累而呈红色。系统发育上不同的 H. rubra 谱系的实验室菌落具有菌落特异性的虾青素含量，这些虾青素在发育过程中（可能在遗传上）是固定的。类胡萝卜素补充和限制实验未能改变菌落内基线水平的虾青素含量，这表明饮食限制并不是导致颜色差异的主要因素。预计负责 H. rubra 和其他甲壳类动物中虾青素生产的一个可能的候选基因产物与真菌中发现的双功能细胞色素 P450 家族 3 酶 CrtS 密切相关。然而，并未发现与被认为能催化鸟类和海龟酮化反应的酶 CYP2J19 的同源物。这项工作是将 H. rubra 红色表型变异与基因型变异联系起来的第一步。未来的工作应集中于（1）查明在膳食类胡萝卜素向虾青素生物转化中起作用的基因，（2）检查哪些基因组变异可能驱动离散谱系之间的着色变化，以及（3）更明确地测试甲壳类动物中条件依赖性类胡萝卜素着色。
Red coloration is a widely distributed phenotype among animals, yet the pigmentary and genetic bases for this phenotype have been described in relatively few taxa. Here we show that the Hawaiian endemic anchialine shrimp Halocaridina rubra is red because of the accumulation of astaxanthin. Laboratory colonies of phylogenetically distinct lineages of H. rubra have colony-specific amounts of astaxanthin that are developmentally, and likely genetically, fixed. Carotenoid supplementation and restriction experiments failed to change astaxanthin content from the within-colony baseline levels, suggesting that dietary limitation is not a major factor driving coloration differences. A possible candidate gene product predicted to be responsible for the production of astaxanthin in H. rubra and other crustaceans is closely related to the bifunctional cytochrome P450 family 3 enzyme CrtS found in fungi. However, homologs to the enzyme thought to catalyze ketolation reactions in birds and turtles, CYP2J19, were not found. This work is one of the first steps in linking phenotypic variation in red coloration of H. rubra to genotypic variation. Future work should focus on (1) pinpointing the genes that function in the bioconversion of dietary carotenoids to astaxanthin, (2) examining what genomic variants might drive variation in coloration among discrete lineages, and (3) testing more explicitly for condition-dependent carotenoid coloration in crustaceans.