The cryptochrome/photolyase (CRY/PL) family is essential for life under sunlight because photolyases repair UV-damaged DNA and cryptochromes are normally part of the circadian clock that controls the activity–sleep cycle within the 24-h day. In this study, we aim to understand how the lineage and habitat of an insect affects its CRY/PL composition. To this end, we searched the large number of annotated protein sequences of 340 insect species already available in databases for CRY/PLs. Using phylogenetic tree and motif analyses, we identified four frequent CRY/PLs in insects: the photolyases 6-4 PL and CPDII PL, as well as the mammalian-type cryptochrome (MCRY) and Drosophila-type cryptochrome (DCRY). Assignment of CRY/PLs to the corresponding insects confirmed that light-exposed insects tend to have more CRY/PLs than insects with little light exposure. Nevertheless, even insects with greatly reduced CRY/PLs still possess MCRY, which can be regarded as the major insect cryptochrome. Only flies of the genus Schizophora, which includes Drosophila melanogaster, lost MCRY. Moreover, we found that MCRY and CPDII PL as well as DCRY and 6-4 PL occur very frequently together, suggesting an interaction between the two pairs.

隐花色素/光裂解酶 (CRY/PL) 家族对于阳光下的生命至关重要，因为光裂解酶可修复紫外线损伤的 DNA，而隐花色素通常是控制 24 小时内活动-睡眠周期的生物钟的一部分。在这项研究中，我们旨在了解昆虫的谱系和栖息地如何影响其 CRY/PL 组成。为此，我们搜索了 CRY/PL 数据库中已有的 340 种昆虫的大量注释蛋白质序列。使用系统发育树和基序分析，我们确定了昆虫中四种常见的 CRY/PL：光解酶 6-4 PL 和 CPDII PL，以及哺乳动物型隐花色素 (MCRY) 和果蝇型隐花色素 (DCRY)。将 CRY/PL 分配给相应的昆虫证实，与光照很少的昆虫相比，光照昆虫往往具有更多的 CRY/PL。尽管如此，即使 CRY/PLs 大大降低的昆虫仍然具有 MCRY，可以将其视为主要的昆虫隐花色素。只有 Schizophora 属的苍蝇，其中包括黑腹果蝇，失去了 MCRY。此外，我们发现 MCRY 和 CPDII PL 以及 DCRY 和 6-4 PL 一起出现的频率非常高，表明这两对之间存在相互作用。