Somatic mutations arise and accumulate during tissue culture and vegetative propagation, potentially affecting various traits in horticultural crops, but their characteristics are still unclear. Here, somatic mutations in regenerated woodland strawberry derived from tissue culture of shoot tips under different conditions and 12 cultivated strawberry individuals are analyzed by whole genome sequencing. The mutation frequency of single nucleotide variants is significantly increased with increased hormone levels or prolonged culture time in the range of 3.3 x 10^–8–3.0 x 10^–6 mutations per site. CG methylation shows a stable reduction (0.71%–8.03%) in regenerated plants, and hypoCG-DMRs are more heritable after sexual reproduction. A high-quality haplotype-resolved genome is assembled for the strawberry cultivar "Beni hoppe." The 12 "Beni hoppe" individuals randomly selected from different locations show 4731–6005 mutations relative to the reference genome, and the mutation frequency varies among the subgenomes. Our study has systematically characterized the genetic and epigenetic variants in regenerated woodland strawberry plants and different individuals of the same strawberry cultivar, providing an accurate assessment of somatic mutations at the genomic scale and nucleotide resolution in plants.

Methods and devices for separating fluid-suspended plant somatic embryos and embryogenic tissue based on differences in their fluid drag properties are disclosed. Deposition method and device for depositing plant somatic embryos into embryo receiver comprising growth substrate by means of a fluid jet is disclosed. An automated system for processing plant somatic embryos from the bioreactor to the growth substrate is also disclosed.

Functional somatic symptoms (FSS) in children account for 10% to 15% of visits in medical services. Few studies have investigated the full range of pediatric FSS and factors linked to the medical help-seeking for young children with these symptoms.

More parental worries, higher symptom severity and impact, and previous contact to medical services are found among the children with FSS who seek medical consultation. Putative risk mechanisms include the early pattern of health care use and parental worries. (Read the full article)

Title: Divorce May Increase Psychosomatic Symptoms in Teens: Study
Category: Health News
Created: 4/27/2015 12:00:00 AM
Last Editorial Review: 4/28/2015 12:00:00 AM

Transposable elements (TEs) can damage genomes, thus organisms use a variety of mechanisms to repress TE expression. The PIWI–piRNA pathway is a small RNA pathway that represses TE expression in the germline of animals. Here we explore the function of the pathway in the somatic stem cells of Hydra, a long-lived freshwater cnidarian. Hydra have three stem cell populations, all of which express PIWI proteins; endodermal and ectodermal epithelial stem cells (ESCs) are somatic, whereas the interstitial stem cells have germline competence. To study somatic function of the pathway, we isolated piRNAs from Hydra that lack the interstitial lineage and found that these somatic piRNAs map predominantly to TE transcripts and display the conserved sequence signatures typical of germline piRNAs. Three lines of evidence suggest that the PIWI–piRNA pathway represses TEs in Hydra ESCs. First, epithelial knockdown of the Hydra piwi gene hywi resulted in up-regulation of TE expression. Second, degradome sequencing revealed evidence of PIWI-mediated cleavage of TE RNAs in epithelial cells using the ping-pong mechanism. Finally, we demonstrated a direct association between Hywi protein and TE transcripts in epithelial cells using RNA immunoprecipitation. Altogether, our data reveal that the PIWI–piRNA pathway represses TE expression in the somatic cell lineages of Hydra, which we propose contributes to the extreme longevity of the organism. Furthermore, our results, in combination with others, suggest that somatic TE repression is an ancestral function of the PIWI–piRNA pathway.

In lung cancer, brain metastasis was associated with somatic amplification of MYC, YAP1, or MMP13.