Quasipaa Boulengeri Research Articles

Study on Detoxification of Biochemical Fulvic Acid on Quasipaa boulengeri Tadpoles under Copper Stress

To understand the detoxification effect of biochemical fulvic acid (BFA) on Quasipaa boulengeri (Q.boulengeri ) tadpoles under copper stress, effects of different concentrations of BFA on growth and physiological indexes of tadpoles. The results showed that the survival rate of tadpoles increased with the increase of BFA concentration. With the increase of BFA concentration, the growth rate of body weight and body length reached the peak at 45 mg/L; The superoxide dismutase(SOD) showed a downward trend in the control group (CK) and an upward trend in each treatment group, with significant difference between the treatment groups (P < 0.05); The content of the malondialdehyde(MDA) and the treatment time and concentration of BFA showed an upward trend in CK group. With the increase of BFA concentration and the content of the MDA decreased, there was significant difference between the treatment groups (P < 0.05). In conclusion, BFA can be used as a detoxification agent under copper stress, and the suitable concentration of BFA is 45 mg/L. This study provides a theoretical basis for the artificial breeding and scientific protection of Q.boulengeri tadpoles.

Comparison between optimized MaxEnt and random forest modeling in predicting potential distribution: A case study with Quasipaa boulengeri in China

Random forest (RF) and MaxEnt models are shallow machine learning approaches that perform well in predicting species' potential distributions. RF models can produce robust results with the default automatic configuration in most cases, but it is necessary for MaxEnt to optimize the model settings to improve the performance, and the predictive performance difference between optimized MaxEnt and RF is uncertain. To explore this issue, the potential distribution of the endangered amphibian Quasipaa boulengeri in China was predicted using optimized MaxEnt and RF models. A total of 408 occurrence data were selected, 1000 locations were generated as pseudo-absence data by the geographic distance method, and 10,000 sites were selected as background data by creating a bias file. Partial ROC at different thresholds and success rate curves were used to compare the predictive performances between optimized MaxEnt and RF. Our results showed that the RF and optimized MaxEnt models both had good performance in predicting the potential distribution of Q. boulengeri, with the RF model performing slightly better whether based on partial ROC or success rate curves. Furthermore, the core suitable habitat regions of Q. boulengeri identified by RF and MaxEnt were similar and were all located in the Sichuan, Chongqing, Hubei, Hunan, and Guizhou provinces. However, the RF model produced a habitat suitability map with higher discrimination and greater heterogeneity. Temperature annual range, mean temperature of the driest quarter, and annual precipitation were the vital environmental variables limiting the distribution of Q. boulengeri. The RF model is the stronger machine learner. We believe it may be more applicable in predicting the native potential distributions of species with sufficient occurrence data, given the additional predictive detail, the simplicity of use, the computational time involved, and the operational complexity.

Using Sex-Linked Markers via Genotyping-by-Sequencing to Identify XX/XY Sex Chromosomes in the Spiny Frog (Quasipaa boulengeri).

We used genotyping-by-sequencing (GBS) to identify sex-linked markers in 43 wild-collected spiny frog (Quasipaa boulengeri) adults from a single site. We identified a total of 1049 putatively sex-linked GBS-tags, 98% of which indicated an XX/XY system, and finally confirmed 574 XY-type sex-linked loci. The sex specificity of five markers was further validated by PCR amplification using a large number of additional individuals from 26 populations of this species. A total of 27 sex linkage markers matched with the Dmrt1 gene, showing a conserved role in sex determination and differentiation in different organisms from flies and nematodes to mammals. Chromosome 1, which harbors Dmrt1, was considered as the most likely candidate sex chromosome in anurans. Five sex-linked SNP makers indicated sex reversals, which are sparsely present in wild amphibian populations, in three out of the one-hundred and thirty-three explored individuals. The variety of sex-linked markers identified could be used in population genetics analyses requiring information on individual sex or in investigations aimed at drawing inferences about sex determination and sex chromosome evolution.

Mountain frog species losing out to climate change around the Sichuan Basin

Amphibians are particularly vulnerable to climate changes that are expected to cause habitat fragmentation and loss and, ultimately, local extirpations. However, little is known about how the interaction between climate change and fragmentation may impede the ability of amphibians to adapt to climate change. Here, we used the iconic mountain frog Quasipaa boulengeri as an indicator species to extrapolate climate-driven shifts in its habitat availability and connectivity in central and southern China according to the minimum and maximum representative concentration pathways. The models projected an average habitat loss of 36%–71% and the in situ and ex situ climate-change refugia to be 29%–64% and 5%–18% of the present-day suitable habitats, respectively. An increase in habitat fragmentation was reflected in a 51% decrease in core patch size, a 9% increase in the mean least-cost path (LCP) length, and a 19% increase in the cost-weighted distance. These climate-driven shifts varied spatially around the Sichuan Basin, with those in the southeast of the Basin being the most pronounced habitat and connectivity losses and those along the Basin being relatively optimistic. The effectiveness of refugia may only be maintained through a narrow passageway along the southern Sichuan Basin because of the presence of LCPs over time. Our results emphasize the need to understand how climate change and connectivity will jointly affect the distribution of mountain amphibians and to accordingly adopt conservation strategies. Further, our findings highlight the importance of identifying and preserving climate-change refugia and habitat connectivity for species persistence and conservation planning.

Transcriptome analysis reveals the effects of temperature on growth in tadpoles of spiny-bellied frog (Quasipaa boulengeri)

Quasipaa boulengeri is consumed as a valuable delicacy in many places in the world. Recent studies showed that water temperature is a very important environmental factor that influences the growth and metamorphosis of reared frog tadpoles. However, the molecular mechanisms of tadpoles in response to water temperature are still unknown. In this study, physiological changes and transcriptomes of tadpoles reared under different water temperatures were analyzed. The results showed that the body length, width, weight, and growth hormone content of tadpoles under 21°C were significantly higher than of those reared at 15°C or 27°C, indicating that frog tadpoles were highly sensitive to water temperature. Further comparative transcriptome analysis of these three groups of tadpoles identified a total of 2001 differentially expressed genes, which were predominantly related to energy metabolism and growth revealed by GO and KEGG enrichment. Importantly, in the GH/IGF signaling pathway, several key genes, including PI3K, ERK1/2, and AMPK, were expressed significantly differently among the three groups, and the expression levels coincided with the changes of phenotype and hormone level. Together, our study provided a suitable rearing temperature (21°C) for tadpoles and contributed to the knowledge of molecular mechanisms underlying tadpoles in response to rearing temperature.

Sex chromosomal dimorphisms narrated by X-chromosome translocation in a spiny frog (Quasipaa boulengeri)

BackgroundIn the general model of sex chromosome evolution for diploid dioecious organisms, the Y (or W) chromosome is derived, while the homogametic sex presumably represents the ancestral condition. However, in the frog species Quasipaa boulengeri, heteromorphisms caused by a translocation between chromosomes 1 and 6 are not related to sex, because the same heteromorphic chromosomes are found both in males and females at the cytological level. To confirm whether those heteromorphisms are unrelated to sex, a sex-linked locus was mapped at the chromosomal level and sequenced to identify any haplotype difference between sexes.ResultsChromosome 1 was assigned to the sex chromosome pair by mapping the sex-linked locus. X-chromosome translocation was demonstrated and confirmed by the karyotypes of the progeny. Translocation heteromorphisms were involved in normal and translocated X chromosomes in the rearranged populations. Based on phylogenetic inference using both male and female sex-linked haplotypes, recombination was suppressed not only between the Y and normal X chromosomes, respectively the Y and translocated X chromosomes, but also between the normal and translocated X chromosomes. Both males and females shared not only the same translocation heteromorphisms but also the X chromosomal dimorphisms in this frog.ConclusionsThe reverse of the typical situation, in which the X is derived and the Y has remained unchanged, is known to be very rare. In the present study, X-chromosome translocation has been known to cause sex chromosomal dimorphisms. The X chromosome has gone processes of genetic differentiation and/or structural changes by chance, which may facilitate sex chromosome differentiation. These sex chromosomal dimorphisms presenting in both sexes may represent the early stages of sex chromosome differentiation and aid in understanding sex chromosome evolution.

Suppressed Recombination of Sex Chromosomes Is Not Caused by Chromosomal Reciprocal Translocation in Spiny Frog (Quasipaa boulengeri).

Chromosome rearrangements (CRs) are perceived to be related to sex chromosome evolution, but it is a matter of controversy whether CRs are the initial causative mechanism of suppressed recombination for sex differentiation. The early stages of sex chromosome evolution in amphibians may represent intermediate states of differentiation, and if so, they potentially shed light on the ultimate cause of suppressed recombination and the role of CRs in sex chromosome differentiation. In this paper, we showed that sex determination differs among 16 populations of spiny frog (Quasipaa boulengeri), in which individuals have normal and rearranged chromosomes caused by reciprocal translocation. In eastern areas, without translocation, genetic differentiation between sexes was relatively low, suggesting unrestricted recombination. In comparison, in western populations that have both normal and translocated chromosomes, a male-heterogametic system and lack of X-Y recombination were identified by male-specific alleles and heterozygote excess. However, such genetic differentiation between sexes in western populations was not directly related to karyotypes, as it was found in individuals with both normal and translocated karyotypes. In the western Sichuan Basin, male-specific and translocation-specific allelic frequency distributions suggested that recombination of sex-differentiation ceased in all populations, but recombination suppression caused by translocation did not exist in some populations. Combined with phylogenetic inference, this indicated that the establishment of sex-linkage had taken place independently of reciprocal translocation, and translocation was not the ultimate cause of sex chromosome differentiation. Furthermore, comparison of the genetic diversity of alleles on Y chromosomes, X chromosomes, and autosomes in western populations showed a reduction of effective population size on sex chromosomes, which may be caused by reciprocal translocation. It indicates that, although it is not the ultimate cause of recombination suppression, reciprocal translocation may enhance sex chromosome differentiation.

Complete mitochondrial genomes of Nanorana taihangnica and N. yunnanensis (Anura: Dicroglossidae) with novel gene arrangements and phylogenetic relationship of Dicroglossidae

BackgroundComplete mitochondrial (mt) genomes have been used extensively to test hypotheses about microevolution and to study population structure, phylogeography, and phylogenetic relationships of Anura at various taxonomic levels. Large-scale mt genomic reorganizations have been observed among many fork-tongued frogs (family Dicroglossidae). The relationships among Dicroglossidae and validation of the genus Feirana are still problematic. Hence, we sequenced the complete mt genomes of Nanorana taihangnica (=F. taihangnica) and N. yunnanensis as well as partial mt genomes of six Quasipaa species (dicroglossid taxa), two Odorrana and two Amolops species (Ranidae), and one Rhacophorus species (Rhacophoridae) in order to identify unknown mt gene rearrangements, to investigate the validity of the genus Feirana, and to test the phylogenetic relationship of Dicroglossidae.ResultsIn the mt genome of N. taihangnica two trnM genes, two trnP genes and two control regions were found. In addition, the trnA, trnN, trnC, and trnQ genes were translocated from their typical positions. In the mt genome of N. yunnanensis, three control regions were found and eight genes (ND6, trnP, trnQ, trnA, trnN, trnC, trnY and trnS genes) in the L-stand were translocated from their typical position and grouped together. We also found intraspecific rearrangement of the mitochondrial genomes in N. taihangnica and Quasipaa boulengeri. In phylogenetic trees, the genus Feirana nested deeply within the clade of genus Nanorana, indicating that the genus Feirana may be a synonym to Nanorana. Ranidae as a sister clade to Dicroglossidae and the clade of (Ranidae + Dicroglossidae) as a sister clade to (Mantellidae + Rhacophoridae) were well supported in BI analysis but low bootstrap in ML analysis.ConclusionsWe found that the gene arrangements of N. taihangnica and N. yunnanensis differed from other published dicroglossid mt genomes. The gene arrangements in N. taihangnica and N. yunnanensis could be explained by the Tandem Duplication and Random Loss (TDRL) and the Dimer-Mitogenome and Non-Random Loss (DMNR) models, respectively. The invalidation of the genus Feirana is supported in this study.

Development of microsatellite markers for the spiny-bellied frog Quasipaa boulengeri (Anura: Dicroglossidae) through transcriptome sequencing

We detected and isolated thirty-two microsatellite loci from transcriptome-derived microsatellite DNA for Quasipaa boulengeri. The isolated loci were all polymorphic and the number of alleles per locus ranged from 2 to 10. The observed and expected heterozygosity per locus varied from 0.1493 to 0.9375 and from 0.1563 to 0.9688, respectively. By multiple comparisons with Bonferroni correction, seven loci were deviated from Hardy–Weinberg equilibrium and significant linkage disequilibrium was detected among twenty-five pairs of loci. Those variable microsatellite sites will be applied to assess gene flow between populations and investigate the evolutionary process of chromosomal polymorphism. Moreover, microsatellite loci were served as a valuable resource for drawing up criterion for the conservation management of this threatened species.

The complete mitochondrial genome of Quasipaa boulengeri (Anura: Dicroglossidae)

Quasipaa boulengeri, an Asian spiny frog that belongs to Neobatrachia, has been reported as a de novo case of chromosomal rearrangements. In this paper, we determined the whole mitochondrial DNA (mtDNA) sequence of Q. boulengeri. The complete mtDNA sequence of Q. boulengeri is 17,741 bp in length, which contains 13 protein-coding genes (PCGs), two rRNAs, 23 tRNAs and one control region. The overall nucleotides base composition of the complete mtDNA is A (28.86%), G (14.43%), C (26.09%), T (30.62%), with a much higher A + T content. Compared to other Neobatrachia species, the mtDNA genome of Q. boulengeri shows a novel gene order at WANCY region.

FISH of 5S rDNA and telomeric (TTAGGG) n repeats in normal and translocated populations of the frog Quasipaa boulengeri (Anura, Ranidae)

Quasipaa boulengeri, a spiny frog, is widely distributed in the low mountain regions, around Sichuan Basin. Our previous study revealed five karyotypes, caused by a translocation, that are randomly distributed throughout different populations. 5S rDNA and telomere sequence (TTAGGG)n are potential good markers for chromosome identification and karyological evolution. In this study, we examined the sequences of 14 populations using fluorescence in situ hybridization (FISH) to detect if there is any variation between karyologically normal and translocated populations. 5S rDNA loci were located at the same position on chromosomes 1 in 7 translocated populations. In two of the seven normal populations, 5S rDNA also occurred on chromosome 5 in addition to chromosome 1. Our findings further indicate that the 5S rDNA on No. 1 most likely represents the ancestral condition, while the minor loci represent the derived state. Signal density variations of the 5S rDNA were observed beteween homologous chromosomes or sister chromatids of pair 1 in both normal and translocated populations. Telomere sequences were identically located on all ends of the 26 chromosomes in seven rearranged populations, however, no ITSs were observed on the translocated chromosomes 1 and 6. Two of the six normal populations were found to contain ITSs which indicates that populations with translocation events diverged prior to those with ITSs rearrangements. In the KKS and BF populations, the ITSs of chromosome 3 are not always found on both homologues. Inter-chromosomal signal strength of telomeric sequences commonly differs within all populations.

A De Novo Case of Floating Chromosomal Polymorphisms by Translocation in Quasipaa boulengeri (Anura, Dicroglossidae)

Very few natural polymorphisms involving interchromosomal reciprocal translocations are known in amphibians even in vertebrates. In this study, thirty three populations, including 471 individuals of the spiny frog Quasipaa boulengeri, were karyotypically examined using Giemsa stain or FISH. Five different karyomorphs were observed. The observed heteromorphism was autosomal but not sex-related, as the same heteromorphic chromosomes were found both in males and females. Our results indicated that the variant karyotypes resulted from a mutual interchange occurring between chromosomes 1 and 6. The occurrence of a nearly whole-arm translocation between chromosome no. 1 and no. 6 gave rise to a high frequency of alternate segregation and probably resulted in the maintenance of the translocation polymorphisms in a few populations. The translocation polymorphism is explained by different frequencies of segregation modes of the translocation heterozygote during meiosis. Theoretically, nine karyomorphs should be investigated, however, four expected karyotypes were not found. The absent karyomorphs may result from recessive lethal mutations, position effects, duplications and deficiencies. The phylogenetic inference proved that all populations of Q. boulengeri grouped into a monophyletic clade. The mutual translocation likely evolved just once in this species and the dispersal of the one karyomorph (type IV) can explain the chromosomal variations among populations.

Isolation and characterization of eleven polymorphic tetranucleotide microsatellite loci for Quasipaa boulengeri (Anura: Dicroglossidae)

We isolated and characterized eleven polymorphic tetranucleotide microsatellite loci in the spiny-bellied frog (Quasipaa boulengeri). The loci were screened in 62 individuals from two natural populations. All loci were variable, with the number of alleles ranging from 8 to 26. The average observed and expected heterozygosity per locus ranged from 0.500 to 0.947 and from 0.735 to 0.932, respectively. Two loci were found to be significant departure from Hardy–Weinberg equilibrium and no significant linkage disequilibrium was detected after sequential Bonferroni corrections. These polymorphic loci will be useful for conservation and population genetics studies of this threated species.