The suborder Notothenioidae is comprised of Antarctic fishes, several of which have lost their ability to rapidly upregulate heat shock proteins in response to thermal stress, instead adopting a pattern of expression resembling constitutive genes. Given the cold-denaturing effect that sub-zero waters have on proteins, evolution in the Southern Ocean has likely selected for increased expression of molecular chaperones. These selective pressures may have also enabled retention of gene duplicates, bolstering quantitative output of cytosolic heat shock proteins (HSPs). Given that newly duplicated genes are under more relaxed selection, it is plausible that gene duplication enabled altered regulation of such highly conserved genes. To test for evidence of gene duplication, copy number of various isoforms within major heat shock gene families were characterized via qPCR and compared between the Antarctic notothen, Trematomus bernacchii, which lost the inducible heat shock response, and the non-Antarctic notothen, Notothenia angustata, which maintains an inducible heat shock response. The results indicate duplication of isoforms within the hsp70 and hsp40 super families have occurred in the genome of T. bernacchii. The findings suggest gene duplications may have been critical in maintaining protein folding efficiency in the sub-zero waters and provided an evolutionary mechanism of alternative regulation of these conserved gene families.

中文翻译：

---

鉴定翡翠岩鳕、Trematomus bernacchii 中热休克蛋白基因家族的基因拷贝数

Notothenioidae 亚目由南极鱼类组成，其中一些已经失去了响应热应激而快速上调热休克蛋白的能力，而是采用了类似于组成基因的表达模式。考虑到低于零水对蛋白质的冷变性作用，南大洋的进化可能选择增加分子伴侣的表达。这些选择压力也可能使基因重复的保留成为可能，从而支持细胞溶质热休克蛋白 (HSP) 的定量输出。鉴于新复制的基因处于更宽松的选择之下，基因复制能够改变对此类高度保守基因的调控是合理的。为了测试基因重复的证据，通过qPCR表征主要热休克基因家族中各种同种型的拷贝数，并在失去诱导性热休克反应的南极野牛和保持诱导性热休克反应的非南极野牛之间进行比较. 结果表明 hsp70 和 hsp40 超家族内的同种型重复发生在 T. bernacchii 的基因组中。研究结果表明，基因重复可能在维持零下水域中的蛋白质折叠效率方面至关重要，并提供了对这些保守基因家族进行替代调控的进化机制。维持可诱导的热休克反应。结果表明 hsp70 和 hsp40 超家族内的同种型重复发生在 T. bernacchii 的基因组中。研究结果表明，基因重复可能在维持零下水域中的蛋白质折叠效率方面至关重要，并提供了对这些保守基因家族进行替代调控的进化机制。维持可诱导的热休克反应。结果表明 hsp70 和 hsp40 超家族内的同种型重复发生在 T. bernacchii 的基因组中。研究结果表明，基因重复可能在维持零下水域中的蛋白质折叠效率方面至关重要，并提供了对这些保守基因家族进行替代调控的进化机制。