Soil seed banks play an important role in the distribution and composition of plant communities in semiarid grassland ecosystems. However, information on how spatial scale influences the spatial heterogeneity of soil ...Soil seed banks play an important role in the distribution and composition of plant communities in semiarid grassland ecosystems. However, information on how spatial scale influences the spatial heterogeneity of soil seed banks in a grassland under grazing disturbance is still lacking. Based on field sampling and greenhouse germination, we measured the species composition and seed density of soil seed banks at different spatial scales （30 mx30 m, 30 mx60 m and 30 mx90 m） along a topographical gradient in a sandy grassland in Horqin Sand Land, Northern China. By applying geostatistical methods, we examined how spatial scale and topography affected the spatial distribution of soil seed banks in the study area. Our results showed that the total number of species in soil seed banks, as well as the number of dominant annuals, increased with the increase of spatial scales. Seed density in soil seed banks decreased with the increase of spatial scales due to an increase in the slopes and relative heights of the sampling points. Geostatistical analysis showed that the relative structural variance （C/（C0＋C）） of seed density and species richness were over 65% for all spatial scales, indicating that these variables had an ob- vious spatial autocorrelation and the spatial structured variance accounted for the largest proportion of the total sample variance. Spatial autocorrelation of seed density in soil seed banks increased with the increase of measured scales, while that of species richness showed a reverse trend. These results suggest that the total number of spe- cies in soil seed banks is spatial scale dependent and lower topography may accommodate more seeds. Spatial distribution of seed density in soil seed banks is also scale dependent due to topographic variation. Grassland management, therefore, needs to consider local grazing disturbance regime, spatial scale and topography.展开更多
SOX10 is a causative gene of Waardenburg syndrome(WS)that is a rare genetic disorder characterized by hearing loss and pigment disturbance.More than 100 mutations of SOX10 have been found in patients with Type 2 WS(WS...SOX10 is a causative gene of Waardenburg syndrome(WS)that is a rare genetic disorder characterized by hearing loss and pigment disturbance.More than 100 mutations of SOX10 have been found in patients with Type 2 WS(WS2),Type 4 WS(WS4),and more complex syndromes.However,no mutation hotspot has been detected in SOX10,and most cases are sporadic,making it difficult to establish a correlation between the high phenotypic and genetic variability.In this study,a duplication of the 321th cytosine(c.321dupC)was introduced into SOX10 in pigs,which induced premature termination of the translation of SOX10(p.K108QfsX45).The premature stop codon in Exon 3 triggered the degradation of mutant mRNA through nonsense-mediated mRNA decay.However,SOX10^(c.321dupC) induced a highly similar phenotype of WS2 with heterogeneous inner ear malformation compared with its adjacent missense mutation SOX10^(c.325A>T).In addition,a site-saturation mutation analysis of the SOX10 N-terminal nuclear localization signal(n-NLS),where these two mutations located,revealed the correlation between SOX10 haploinsufficiency and WS by an in vitro reporter assay.The analysis combining the in vitro assay with clinical cases may provide a clue to clinical diagnoses.展开更多
基金funded by the National Natural Science Foundation of China(41171414)the Knowledge Innovation Program of Chinese Academy of Sciences(KZCX2-EW-QN313)+2 种基金the National Science and Technology Support Program (2011BAC07B02)the National Basic Research Program of China(2009CB421303)the West Light Foundation of the Chinese Academy of Sciences(0928711001)
文摘Soil seed banks play an important role in the distribution and composition of plant communities in semiarid grassland ecosystems. However, information on how spatial scale influences the spatial heterogeneity of soil seed banks in a grassland under grazing disturbance is still lacking. Based on field sampling and greenhouse germination, we measured the species composition and seed density of soil seed banks at different spatial scales （30 mx30 m, 30 mx60 m and 30 mx90 m） along a topographical gradient in a sandy grassland in Horqin Sand Land, Northern China. By applying geostatistical methods, we examined how spatial scale and topography affected the spatial distribution of soil seed banks in the study area. Our results showed that the total number of species in soil seed banks, as well as the number of dominant annuals, increased with the increase of spatial scales. Seed density in soil seed banks decreased with the increase of spatial scales due to an increase in the slopes and relative heights of the sampling points. Geostatistical analysis showed that the relative structural variance （C/（C0＋C）） of seed density and species richness were over 65% for all spatial scales, indicating that these variables had an ob- vious spatial autocorrelation and the spatial structured variance accounted for the largest proportion of the total sample variance. Spatial autocorrelation of seed density in soil seed banks increased with the increase of measured scales, while that of species richness showed a reverse trend. These results suggest that the total number of spe- cies in soil seed banks is spatial scale dependent and lower topography may accommodate more seeds. Spatial distribution of seed density in soil seed banks is also scale dependent due to topographic variation. Grassland management, therefore, needs to consider local grazing disturbance regime, spatial scale and topography.
基金The authors thank Dr.Yi Wu and Na Chen for help with three-dimensional reconstruction.They also thank Dr.Lei Chen for providing plasmids.This study was supported by grants from the National Natural Science Foundation of China,China(81670941 and 81670940)the National Science and Technology Major Project for Transgenic Organisms(2016ZX08009-003 and 2018ZX08010-10B),China.
文摘SOX10 is a causative gene of Waardenburg syndrome(WS)that is a rare genetic disorder characterized by hearing loss and pigment disturbance.More than 100 mutations of SOX10 have been found in patients with Type 2 WS(WS2),Type 4 WS(WS4),and more complex syndromes.However,no mutation hotspot has been detected in SOX10,and most cases are sporadic,making it difficult to establish a correlation between the high phenotypic and genetic variability.In this study,a duplication of the 321th cytosine(c.321dupC)was introduced into SOX10 in pigs,which induced premature termination of the translation of SOX10(p.K108QfsX45).The premature stop codon in Exon 3 triggered the degradation of mutant mRNA through nonsense-mediated mRNA decay.However,SOX10^(c.321dupC) induced a highly similar phenotype of WS2 with heterogeneous inner ear malformation compared with its adjacent missense mutation SOX10^(c.325A>T).In addition,a site-saturation mutation analysis of the SOX10 N-terminal nuclear localization signal(n-NLS),where these two mutations located,revealed the correlation between SOX10 haploinsufficiency and WS by an in vitro reporter assay.The analysis combining the in vitro assay with clinical cases may provide a clue to clinical diagnoses.
