Spatial and temporal population genetic variation and structure of Nothotsuga longibracteata (Pinaceae), a relic conifer species endemic to subtropical China

Nothotsuga longibracteata, a relic and endangered conifer species endemic to subtropical China, was studied for examining the spatial-temporal population genetic variation and structure to understand the historical biogeographical processes underlying the present geographical distribution. Ten populations were sampled over the entire natural range of the species for spatial analysis, while three key populations with large population sizes and varied age structure were selected for temporal analyses using both nuclear microsatellites (nSSR) and chloroplast microsatellites (cpSSR). A recent bottleneck was detected in the natural populations of N. longibracteata. The spatial genetic analysis showed significant population genetic differentiation across its total geographical range. Notwithstanding, the temporal genetic analysis revealed that the level of genetic diversity between different age class subpopulations remained constant over time. Eleven refugia of the Last Glacial Maximum were identified, which deserve particular attention for conservation management

Increased NMDARs in neurons and glutamine synthetase in astrocytes underlying autistic-like behaviors of Gabrb1−/− mice

Summary: Mutations of the GABA-A receptor subunit β1 (GABRB1) gene are found in autism patients. However, it remains unclear how mutations in Gabrb1 may lead to autism. We generated Gabrb1−/− mouse model, which showed autistic-like behaviors. We carried out RNA-seq on the hippocampus and found glutamatergic pathway may be involved. We further carried out single-cell RNA sequencing on the whole brain followed by qRT-PCR, immunofluorescence, electrophysiology, and metabolite detection on specific cell types. We identified the up-regulated Glul/Slc38a3 in astrocytes, Grin1/Grin2b in neurons, glutamate, and the ratio of Glu/GABA in the hippocampus. Consistent with these results, increased NMDAR-currents and reduced GABAAR-currents in the CA1 neurons were detected in Gabrb1−/− mice. NMDAR antagonist memantine or Glul inhibitor methionine sulfoximine could rescue the abnormal behaviors in Gabrb1−/− mice. Our data reveal that upregulation of the glutamatergic synapse pathway, including NMDARs at neuronal synapses and glutamine exported by astrocytes, may lead to autistic-like behaviors