Genes & genetic systems最新文献

The long-tailed hamster Cricetulus longicaudatus is a dominant rodent in farmland of Shanxi Province, China, but little is known about its genetic diversity and population structure. In this study, the genomic DNAs of individuals from 13 populations captured in different fields of Shanxi were extracted and amplified by six pairs of microsatellite primers and by universal primers for mtDNA COI gene sequences. Our data revealed significant departure from Hardy-Weinberg equilibrium in four of the 13 populations. In all 13 populations, the mean observed heterozygosity was significantly lower than the expected heterozygosity. Meanwhile, the mean inbreeding coefficient was statistically significant, which indicated non-random mating within populations. The pairwise genetic distance and natural logarithm of linear geographical distance were not significantly correlated for any C. longicaudatus populations. However, the correlation between genetic distance and resistance distance based on mountain landscape was significant, suggesting that the mountain landscape is an important factor affecting gene flow of C. longicaudatus. Pairwise F_ST analysis of population structure showed moderate to high genetic differentiation among populations, and all individuals could be divided into two gene clusters. Phylogenetic analysis based on COI sequences also showed that many individuals originated from a single haplotype, suggesting the existence of gene exchange among these populations at some time in the past. Our research should provide a scientific basis for the analysis of genetic differentiation and gene flow among populations of C. longicaudatus.

Species identification using molecular techniques has recently become common for various taxa. Loop-mediated isothermal amplification (LAMP) is one of the easiest and least expensive molecular identification methods. Although few studies have developed LAMP assays for amphibians, we believe that LAMP is also useful for identifying endangered amphibians. Hynobius tokyoensis and H. lichenatus occur in Honshu, Japan, and have parapatric distributions. They are similar morphologically, especially at early developmental stages, including eggs and larvae. Hynobius tokyoensis has been listed as a national endangered species in Japan since 2020, and unambiguous identification of these species is therefore important for their conservation and management. In this study, we developed a LAMP primer set for the mitochondrial cytochrome b region to detect H. tokyoensis, and we evaluated the LAMP assay using total genomic DNA from four H. tokyoensis and three H. lichenatus individuals from across most of their ranges. Our LAMP primer set could distinguish these two species. This study should help to establish LAMP assays for other endangered species and morphologically similar species.

Rhododendron purdomii (Ericaceae) is an endangered ornamental species endemic to the Qinling Mountains of China. Due to the impact of climate change and human disturbance, R. purdomii is threatened by habitat loss, and conservation of this species is urgently needed. In this study, we developed and characterized 13 novel microsatellite markers for R. purdomii based on next-generation sequencing data. For the 13 microsatellite markers in three R. purdomii populations, the number of alleles ranged from two to 12, the number of effective alleles was from 1.000 to 8.892, Shannon's information index was from 0.000 to 2.320, and the observed and expected heterozygosity were from 0.000 to 1.000 and from 0.000 to 0.888, respectively. Private alleles were found in all three populations. Moderate differentiation between population pairs was indicated by pairwise F_ST values. The microsatellite markers developed in this study will provide opportunities for examining the genetic diversity and population structure of R. purdomii and contribute to the effective conservation of this species.

Epigenome information mediates genome function and maintenance by regulating gene expression and chromatin organization. Because the epigenome pattern can change in response to internal and external environments, it may underlie an adaptive genome response that modulates phenotypes during development and in changing environments. Here I summarize recent progress in our understanding of how epigenome patterns are shaped and modulated by concerted actions of silencing and anti-silencing factors mainly in Arabidopsis thaliana. I discuss the dynamic nature of epigenome regulation, which is realized by cooperation and counteraction among silencing and anti-silencing factors, and how the dynamic epigenome mediates robust and plastic responses of plants to fluctuating environments.

Plant adaptation to high temperature, often referred to as heat acclimation, is a process in which exposure to moderately high temperatures increases a plant's tolerance to subsequent (normally) lethal high temperatures. Plants store heat experience information (heat memory) obtained from previous exposure to high temperatures for several days and develop future temperature responsiveness. However, our understanding of heat acclimation is very limited. In the model plant Arabidopsis thaliana, changes in the expression patterns of heat memory genes play a central role in regulating plant survival and adaptation to recurring heat stress. Heat stress-related transcription factors and histone-modifying enzymes function in the sensitized expression of heat memory genes via the deposition and removal of histone modifications. Chromatin-remodeling complexes and miRNA accumulation also trigger the sustained expression of heat memory genes. In this review, I describe studies of heat acclimation that have provided important insights into the molecular mechanisms that lead to flexible and reversible gene expression upon heat stress in plants.