scholarly journals Up-regulation of cryptochrome 1 gene expression in cotton bollworm (Helicoverpa armigera) during migration over the Bohai Sea

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8071
Author(s):  
Liyu Yang ◽  
Yingjie Liu ◽  
Philip Donkersley ◽  
Pengjun Xu
Keyword(s):  
Helicoverpa Armigera ◽  
Negative Selection ◽  
Bohai Sea ◽  
Purifying Selection ◽  
Migration Behavior ◽  
Negative Selection Pressure ◽  
Strong Negative Selection ◽  
Helicoverpa Armígera ◽  
Novel Transcripts ◽  
Cryptochrome 1

Cryptochromes (CRYs) are flavoproteins and play a pivotal role in circadian clocks which mediate behavior of organisms such as feeding, mating and migrating navigation. Herein, we identified novel transcripts in Helicoverpa armigera of six isoforms of cry1 and seven isoforms of cry2 by Sanger sequencing. Phylogenetic analysis showed that the transcripts of cry1 and cry2 align closely with other insect crys, indicating within-species divergence of Hacry. A dn/ds analysis revealed that the encoding sequence of the cry1 was under purifying selection by a strong negative selection pressure whereas the cry2 was less constraint and showed a less strong purification selection than cry1. In general, Hacrys were more abundantly transcribed in wild migrating populations than that in laboratory maintained populations, and expression of the cry2 was lower than cry1 in all samples tested. Moreover, when compared with the migrating parental population, offspring reared in laboratory conditions showed a significant reduction on transcription of the cry1 but not cry2. These results strongly suggest that cry1 was more related to the migration behavior of H. armigera than cry2.

scholarly journals Identification of Genes under Purifying Selection in Human Cancers

2017 ◽  
Author(s):  
Robert A. Mathis ◽  
Ethan S. Sokol ◽  
Piyush B. Gupta
Keyword(s):  
Negative Selection ◽  
Somatic Mutations ◽  
Purifying Selection ◽  
Sequencing Data ◽  
Systematic Assessment ◽  
Coding Regions ◽  
Strong Negative Selection ◽  
Cancer Genomes ◽  
Lung Adenocarcinomas ◽  
Widespread Interest

AbstractThere is widespread interest in finding therapeutic vulnerabilities by analyzing the somatic mutations in cancers. Most analyses have focused on identifying driver oncogenes mutated in patient tumors, but this approach is incapable of discovering genes essential for tumor growth yet not activated through mutation. We show that such genes can be systematically discovered by mining cancer sequencing data for evidence of purifying selection. We show that purifying selection reduces substitution rates in coding regions of cancer genomes, depleting up to 90% of mutations for some genes. Moreover, mutations resulting in non-conservative amino acid substitutions are under strong negative selection in tumors, whereas conservative substitutions are more tolerated. Genes under purifying selection include members of the EGFR and FGFR pathways in lung adenocarcinomas, and DNA repair pathways in melanomas. A systematic assessment of purifying selection in tumors would identify hundreds of tumor-specific enablers and thus novel targets for therapy.

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