The highest-elevation frog provides insights into mechanisms and evolution of defenses against high UV radiation

Abstract

Defense against ultraviolet (UV) radiation exposure is essential for survival, especially in high-elevation species. Although some specific genes involved in UV response have been reported, the full view of UV defense mechanisms remains largely unexplored. Herein, we used integrated approaches to analyze UV responses in the highest-elevation frog, Nanorana parkeri . We show less damage and more efficient antioxidant activity in skin of this frog than those of its lower-elevation relatives after UV exposure. We also reveal genes related to UV defense and a corresponding temporal expression pattern in N. parkeri . Genomic and metabolomic analysis along with large-scale transcriptomic profiling revealed a time-dependent coordinated defense mechanism in N. parkeri . We also identified several microRNAs that play important regulatory roles, especially in decreasing the expression levels of cell cycle genes. Moreover, multiple defense genes (i.e., TYR for melanogenesis) exhibit positive selection with function-enhancing substitutions. Thus, both expression shifts and gene mutations contribute to UV adaptation in N. parkeri . Our work demonstrates a genetic framework for evolution of UV defense in a natural environment.

Mutations in SLC45A2 lead to loss of melanin in parrot feathers

“…These changes also contribute to differences in skin tone and skin aging in various human populations. In animals, equivalent gene mutations result in lighter pigmentation in species like gorillas ( Prado-Martinez et al 2013 ), dogs ( Caduff et al 2017 ), tigers ( Xu et al 2017 ), horses ( Sevane et al 2019 ), mice ( Le et al 2020 ), shrews ( Tsuboi et al 2009 ), chickens ( Gunnarsson et al 2007 ), quails ( Gunnarsson et al 2007 ), pigeons, ( Domyan et al 2014 ), frogs ( Fu et al 2022 ), and fish ( Segev-Hadar et al 2021 ). OCA4 patients have low pigmentation levels and show similarities to OCA2 patients who lack a melanosomal chloride channel ( Bellono et al 2014 ).…”

Homology in Sex Determination in Two Distant Spiny Frogs, Nanorana quadranus and Quasipaa yei

“…Based on the close phylogenetic relationships, the Quasipaa spinosa genome and the Nanorana parkeri genome were selected as the reference genomes [45,46]. We used the direct mapping method to determine the chromosomal location of sex-linked markers.…”

“…Subsequently, we extended and trimmed the alignment regions and aligned them with the sex-linked loci to determine whether any sex-linked loci were located within those regions. Here, the Q. spinosa and N. parkeri genomes were selected as reference genomes based on their close phylogenetic relationships [45,46].…”

The tale of the black viper: distribution and bioclimatic niche modelling of melanistic Vipera aspis in Italy

“…According to the thermal melanism hypothesis, in areas with low temperatures, melanistic individuals are advantaged because they warm-up faster and maintain optimal body temperatures more easily (Jong, et al, 1996;Clusella-Trullas et al, 2007b;. Furthermore, melanistic phenotypes appear to be less susceptible to the damaging effects of UV rays (Fu et al 2022). Nonetheless, the extent of this phenomenon and the molecular mechanisms underlying it in ectotherms are still debated (see Chang and Zheng, 2003;Reguera et al, 2014;Jin et al 2020;Senczuk et al 2021).…”