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While the capacity to regenerate tissues or limbs is limited in mammals, including humans, axolotls are able to regrow entire limbs and major organs after incurring a wound. The wound blastema has been extensively studied in limb regeneration. However, due to the inadequate characterization of ECM and cell subpopulations involved in the regeneration process, the discovery of the key drivers for human limb regeneration remains unknown. In this study, we applied large-scale single-cell RNA sequencing to classify cells throughout the adult axolotl limb regeneration process, uncovering a novel regeneration-specific mitochondria-related cluster supporting regeneration through energy providing and the ECM secretion (COL2+) cluster contributing to regeneration through cell–cell interactions signals. We also discovered the dedifferentiation and re-differentiation of the COL1+/COL2+ cellular subpopulation and exposed a COL2-mitochondria subcluster supporting the musculoskeletal system regeneration. On the basis of these findings, we reconstructed the dynamic single-cell transcriptome of adult axolotl limb regenerative process, and identified the novel regenerative mitochondria-related musculoskeletal populations, which yielded deeper insights into the crucial interactions between cell clusters within the regenerative microenvironment.

The phylogeography of Schizothorax waltoni , an endemic and endangered tetraploid schizothoracine fish in the Yarlung Tsangpo River (YLTR) on southern margin of Qinghai-Tibet Plateau (QTP), was investigated using two mitochondrial DNA regions and eleven microsatellite loci. Analyses of concatenated sequences of cytochrome b (1141 bp) and the control region (712 bp) revealed high haplotype diversity and moderate nucleotide diversity. High genetic diversity was observed based on microsatellite variation. Both mtDNA and microsatellite analyses revealed significant genetic differentiation between the eastern population (Mainling) and the other four populations to the west, and non-significant genetic differentiation amongst the three central populations in the west. Significant genetic differentiation was observed between the western population (Shigatse) and the three central populations based on microsatellite analyses alone. Bayesian skyline plot analyses showed that S. waltoni experienced a pronounced population expansion 0.05 to 0.10 Ma. Hierarchical structure analyses of microsatellite data indicated that S. waltoni could be split into three groups (western, central and eastern YLTR). The results indicate that three management units should be considered for S. waltoni . Our findings highlight the need for the conservation and effective management of S. waltoni , which is a key member of the endemic and highly threatened fishes of the QTP.

Studies of genetic diversity and population genetic structure in deep-sea fauna mainly focus on vulnerable marine ecosystem (VME) indicator taxa, whilst relatively few studies have focussed on VME-associated taxa whose distributions are not exclusively limited to VMEs. Knowledge of genetic connectivity (gene flow) amongst populations of VME-associated taxa, such as squat lobsters, will contribute to ongoing management decision-making related to the protection of VMEs. To better understand the genetic diversity and genetic structure of squat lobster populations (Munida isos, M. endeavourae and M. gracilis) at different spatial scales (biogeographic provinces, regions, and geomorphic features) in the southwest Pacific Ocean, mitochondrial COI region and nuclear microsatellite markers were employed. Overall, the levels of genetic diversity were high for the COI region and moderate for the microsatellite loci across the three Munida species. AMOVA of COI variation revealed no significant genetic differentiation, whereas AMOVA of microsatellite variation revealed significant genetic differentiation amongst the three species, but at different spatial scales. Based on microsatellite variation, a range of analyses (Structure, PCoA, DAPC) provided some evidence of limited genetic differentiation at different spatial scales across the three species. Low to moderate levels of assignment success (~40–60%) based on microsatellite variation were achieved for the three Munida species, suggesting high levels of gene flow and possible panmixia. Nonetheless, for Munida isos, populations from the Tasmanian slope were genetically differentiated from all other populations and may act as source populations, whereas populations from the Kermadec Ridge region may be sink populations for all three Munida species. Our results highlight the need to consider gene flow at trans-national scales when managing anthropogenic impacts on VMEs. The results are discussed in the context of existing marine protected areas, which can contribute new information useful to the management of VMEs within the southwest Pacific Ocean.

Major threats to freshwater fish diversity now include loss of native genetic diversity as a consequence of translocations of fishes between sites and from hatcheries to sites, and small effective population sizes resulting from overfishing and/or habitat loss. Ten polymorphic microsatellite markers were employed to evaluate genetic diversity, population genetic structure and gene flow amongst nine populations of the ecologically and economically important fish, the northern snakehead (Channa argus), in three river systems in central China. Multiple analyses revealed evidence of high genetic diversity and pronounced subdivision based on both regional separation and on river systems. A lack of evidence of genetic bottleneck over recent generations was consistent with the long-term stability of population size and contemporary distribution. The effective population sizes for most C. argus populations were small, suggesting the need for future conservation efforts focusing on these populations. Different lines of evidence point to the local enhancement of stocks by both aquaculture-reared fish and the transfer of wild fish. This study illustrates how human activities may affect genetic diversity and population genetic structure of C. argus populations, and highlights the need for new management regimes to protect native freshwater fish genetic diversity.

The Qinghai-Tibet Plateau (QTP) is a biodiversity hotspot, resulting from its geological history, contemporary environment and isolation. Uplift of the QTP and Quaternary climatic oscillations are hypothesised to have influenced the genetic diversity, population structure and dynamics of all QTP endemic species. In this study, we tested this hypothesis by assaying variation at two mitochondrial DNA regions (cytochrome b and control region) and at 12 microsatellite loci of seven populations of the endemic fish, Schizothorax o’connori from the Yarlung Tsangpo River (YLTR) on the QTP. Analyses revealed one group of six populations to the west, above the Yarlung Tsangpo Grand Canyon (YTGC), and a second group to the east below the YTGC. Estimates of the timing of this east-west split indicate that these groups represent evolutionarily significant units that have evolved separately and rapidly in the middle Pleistocene, at the time of the Kunlun-Huanghe Movement A Phase and the Naynayxungla glaciation. Population dynamic analyses indicate that S. o’connori experienced a pronounced late Pleistocene expansion during the last interglacial period. The results of this study support the hypotheses that the QTP uplift and Quaternary climatic oscillations have played important roles in shaping the population genetics and dynamics of this endemic fish.

Channa argus is one of the most important economic fish species in China. However, there is limited genetic information on its population structure and genetic diversity. Nineteen novel polymorphic microsatellite loci were isolated and characterized in 42 individuals from one natural population collected from the Poyang Lake in Jiangxi Province. The number of alleles per locus ranged from 5 to 18 with an average of 11.16. The observed and expected heterozygosities ranged from 0.214 to 1.000 and from 0.630 to 0.923, respectively. The average polymorphic information content value was 0.814. Among these polymorphic microsatellites, eleven loci conformed to Hardy–Weinberg equilibrium. These microsatellite loci are currently being used to assess the genetic diversity and population structure of C. argus and will contribute to the effective conservation and rational utilization of genetic resources of this species.

Twenty-three polymorphic microsatellite loci were isolated from Schizothorax macropogon and were characterized in 42 individuals collected from the Yarlung Tsangpo River in Tibet, China. The number of alleles per locus ranged from 5 to 32 with an average of 20.17. The expected heterozygosity and Shannon-Wiener diversity index ranged from 0.709 to 0.951 and from 1.421 to 3.183, respectively. These microsatellite loci will be valuable for the evaluation of genetic diversity and population genetic structure of S. macropogon.

Munida isos is a deep sea squat lobster species that is widely distributed across the New Zealand and east Australian region, and is often associated with deep sea vulnerable marine ecosystems. To investigate its population genetic structure and patterns of regional connectivity, microsatellite loci were developed for M. isos from two genomic libraries using the Illumina HiSeq 2500 sequencing platform. Twenty-six loci amplified consistently in M. isos from the Tasman Sea, among which 20 were polymorphic and selectively neutral. Evidence of null alleles was observed at eight loci. Most loci exhibited moderate to high levels of polymorphism, with an average polymorphic information content value of 0.482. The mean number of alleles per locus was 7.45, with a mean expected heterozygosity of 0.520. Thirteen loci exhibited significant deviation from Hardy–Weinberg equilibrium, while only one locus pair was in linkage disequilibrium after false discovery rate correction for multiple testing ( P<0.05 ). Cross-species amplification tests revealed that the transferability of 14 loci (70%) was positive for the two congeners M. endeavourae and M. gracilis. The accessibility to new polymorphic microsatellite loci will facilitate population genetic studies and aid in developing conservation and management strategies for vulnerable marine ecosystems.

The difluoromethyl group is a crucial fluorinated moiety with distinctive biological properties, and the synthesis of chiral CF₂H-containing analogs has been recognized as a powerful strategy in drug design. To date, the most established method for accessing enantioenriched difluoromethyl compounds involves the enantioselective functionalization of nucleophilic and electrophilic CF₂H synthons. However, this approach is limited by lower reactivity and reduced enantioselectivity. Leveraging the unique fluorine effect, we design and synthesize a radical CF₂H synthon by incorporating isoindolinone into alkyl halides for asymmetric radical transformation. Here, we report an efficient strategy for the asymmetric construction of carbon stereocenters featuring a difluoromethyl group via nickel-catalyzed Negishi cross-coupling. This approach demonstrates mild reaction conditions and excellent enantioselectivity. Given that optically pure difluoromethylated amines and isoindolinones are key structural motifs in bioactive compounds, this strategy offers a practical solution for the efficient synthesis of CF₂H-containing chiral drug-like molecules. The difluoromethyl group is a crucial fluorinated moiety, and the synthesis of chiral CF₂H-containing analogs is a powerful strategy in drug design and screening. Here, the authors report a strategy for the asymmetric construction of carbon stereocenters featuring a difluoromethyl group via nickel-catalyzed Negishi cross-coupling.