Zoological Research

3-13

Authors: Laxman Khanal;Mukesh Kumar Chalise;Peng-Fei Fan;Randall C. Kyes;Xue-Long Jiang

Phylogenetic relationships within the sinica-group of macaques based on morphological, behavioral, and molecular characteristics have remained controversial. The Nepal population of Assam macaques (Macaca assamensis) (NPAM), the westernmost population of the species, is morphologically distinct but has never been used in phylogenetic analyses. Here, the phylogenetic relationship of NPAM with other congeners was tested using multiple mitochondrial and Y-chromosomal loci. The divergence times and evolutionary genetic distances among macaques were also estimated. Results revealed two major mitochondrial DNA clades of macaques under the sinica-group: the first clade included M. thibetana, M. sinica, and eastern subspecies of Assam macaque (M. assamensis assamensis); the second clade included M. radiata together with species from the eastern and central Himalaya, namely, M. leucogenys, M. munzala, and NPAM. Among the second-clade species, NPAM was the first to diverge from the other members of the clade around 1.9 million years ago. Our results revealed that NPAM is phylogenetically distinct from the eastern Assam macaques and closer to other species and hence may represent a separate species. Because of its phylogenetic distinctiveness, isolated distribution, and small population size, the Nepal population of sinica-group macaques warrants detailed taxonomic revision and high conservation priority.

28-42

Authors: Chuan-Ling Zhang;Yi-Jia Li;Shuang Lu;Ting Zhang;Rui Xiao;Huai-Rong Luo

Depression is a prevalent mental disorder that is associated with aging and contributes to increased mortality and morbidity. The overall prevalence of geriatric depression with clinically significant symptoms is currently on the rise. Recent studies have demonstrated that altered expressions of long non-coding RNAs (lncRNAs) in the brain affect neurodevelopment and manifest modulating functions during the depression. However, most lncRNAs have not yet been studied. Herein, we analyzed the transcriptome of dysregulated lncRNAs to reveal their expressions in a mouse model exhibiting depressive-like behaviors, as well as their corresponding response following antidepressant fluoxetine treatment. A chronic unpredictable mild stress (CUMS) mouse model was applied. A six-week fluoxetine intervention in CUMS-induced mice attenuated depressive-like behaviors. In addition, differential expression analysis of lncRNAs was performed following RNA-sequencing. A total of 282 lncRNAs (134 up-regulated and 148 down-regulated) were differentially expressed in CUMS-induced mice relative to non-stressed counterparts (P<0.05). Moreover, 370 differentially expressed lncRNAs were identified in CUMS-induced mice after fluoxetine intervention. Gene Ontology (GO) analyses showed an association between significantly dysregulated lncRNAs and protein binding, oxygen binding, and transport activity, while the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that these dysregulated lncRNAs might be involved in inflammatory response pathways. Fluoxetine effectively ameliorated the symptoms of depression in CUMS-induced mice by regulating the expression of lncRNAs in the hippocampus. The findings herein provide valuable insights into the potential mechanism underlying depression in elderly people.

51-61

Authors: Zong-Ji Wang;Guang-Ji Chen;Guo-Jie Zhang; Qi Zhou

Palaeognathae includes ratite and tinamou species that are important for understanding early avian evolution. Here, we analyzed the whole-genome sequences of 15 paleognathous species to infer their demographic histories, which are presently unknown. We found that most species showed a reduction of population size since the beginning of the last glacial period, except for those species distributed in Australasia and in the far south of South America. Different degrees of contraction and expansion of transposable elements (TE) have shaped the paleognathous genome architecture, with a higher transposon removal rate in tinamous than in ratites. One repeat family, AviRTE, likely underwent horizontal transfer from tropical parasites to the ancestor of little and undulated tinamous about 30 million years ago. Our analysis of gene families identified rapid turnover of immune and reproduction-related genes but found no evidence of gene family changes underlying the convergent evolution of flightlessness among ratites. We also found that mitochondrial genes have experienced a faster evolutionary rate in tinamous than in ratites, with the former also showing more degenerated W chromosomes. This result can be explained by the Hill-Robertson interference affecting genetically linked W chromosomes and mitochondria. Overall, we reconstructed the evolutionary history of the Palaeognathae populations, genes, and TEs. Our findings of co-evolution between mitochondria and W chromosomes highlight the key difference in genome evolution between species with ZW sex chromosomes and those with XY sex chromosomes.

87-93

Authors: Jacobo Pardo-Seco;Alberto Gómez-Carballa;Xabier Bello;Federico Martinón-Torres;Antonio Salas

Analysis of SARS-CoV-2 genome variation using a minimal number of selected informative sites conforming a genetic barcode presents several drawbacks. We show that purely mathematical procedures for site selection should be supervised by known phylogeny (i) to ensure that solid tree branches are represented instead of mutational hotspots with poor phylogeographic proprieties, and (ii) to avoid phylogenetic redundancy. We propose a procedure that prevents information redundancy in site selection by considering the cumulative informativeness of previously selected sites (as a proxy for phylogenetic-based criteria). This procedure demonstrates that, for short barcodes (e.g., 11 sites), there are thousands of informative site combinations that improve previous proposals. We also show that barcodes based on worldwide databases inevitably prioritize variants located at the basal nodes of the phylogeny, such that most representative genomes in these ancestral nodes are no longer in circulation. Consequently, coronavirus phylodynamics cannot be properly captured by universal genomic barcodes because most SARS-CoV-2 variation is generated in geographically restricted areas by the continuous introduction of domestic variants.

100-107

Authors: Ting-Li Hu;Feng Cheng;Zhen Xu;Zhong-Zheng Chen;Lei Yu;Qian Ban;Chun-Lin L;Tao Pan;Bao-Wei Zhang

In this study, we reassessed the taxonomic position of Typhlomys (Rodentia: Platacanthomyidae) from Huangshan, Anhui, China, based on morphological and molecular evidence. Results suggested that Typhlomys is comprised of up to six species, including four currently recognized species (Typhlomys cinereus, T. chapensis, T. daloushanensis, and T. nanus), one unconfirmed candidate species, and one new species (Typhlomys huangshanensis sp. nov.). Morphological analyses further supported the designation of the Huangshan specimens found at mid-elevations in the southern Huangshan Mountains (600 m to 1 200 m a.s.l.) as a new species.

116-123

Authors: Li-Mei Yuan;Xi-Ling Deng;De-Chun Jiang;Sebastian Klaus;Nikolai L. Orlov;Kong Yang;Jia-Tang Li

Currently, the genus Polypedates comprises 26 species distributed in South, Southeast, and East Asia. Because of their relatively low dispersal capability and intolerance to seawater, this genus is ideal for the study of terrestrial range evolution that extends into the island archipelagos of southeastern Asia. In this study, based on data compiled for Polypedates from previous studies and partial mitochondrial and nuclear genes collected in this study, we performed systematic biogeographical analysis. We confirmed a Sundaland origin for the extant genus and showed northward dispersal into mainland Southeast Asia and Asia, which coincided with the timing of paleoclimatic change from the Oligocene to Middle Miocene. Climate fluctuations had a profound impact on species diversification within the genus Polypedates. Furthermore, the Red River did not mediate species exchange between Southeast Asia and mainland Asia until the end of the Miocene, with the sudden onset of northward dispersal in several clades independently at that time. Alternatively, the lineage of widespread insular P. leucomystax strongly supports the hypothesis of terrestrial connection between island archipelagos of Southeast Asia during the Mid-Pleistocene paleoclimate fluctuations. Our biogeographical analysis also supports the recent introduction of P. leucomystax to the Philippines and Ryukyus, as previously suggested.

130-134

Authors: Wang-Xiao Xia;Hao-Rong Li;Jing-Hao Ge;Yao-Wu Liu;Hong-Hui Li;Yan-Hua Su;Hai-Zhen Wang;Hui-Fang Guo;Yu-Xuan Dai;Yao-Wen Liu;Xing-Chun Gou

The Atlantic sea nettle (Chrysaora quinquecirrha) has an important evolutionary position due to its high ecological value. However, due to limited sequencing technologies and complex jellyfish genomic sequences, the current C. quinquecirrha genome assembly is highly fragmented. Here, we used the most advanced high-throughput chromosome conformation capture (Hi-C) technology to obtain high-coverage sequencing data of the C. quinquecirrha genome. We then anchored these data to the previously published contig-level assembly to improve the genome. Finally, a high-continuity genome sequence of C. quinquecirrha was successfully assembled, which contained 1 882 scaffolds with a N50 length of 3.83 Mb. The N50 length of the genome assembly was 5.23 times longer than the previously released one, and additional analysis revealed that it had a high degree of genomic continuity and accuracy. Acquisition of the high-continuity genome sequence of C. quinquecirrha not only provides a basis for the study of jellyfish evolution through comparative genomics but also provides an important resource for studies on jellyfish growth and development.