Year: 2022

CIS AND TRANS EPIGENETIC SIGNALS. “As long as a transcriptional response is self-sustaining in the absence of the originating stimulus, it can be categorized as epigenetic. This can be achieved by self-propagating trans-acting mechanisms, or by cis-acting molecular signatures physically associated with the DNA sequence they regulate.” https://lnkd.in/dteycy7 View in LinkedIn

SUBSET CIS PATH. "With the cis epigenetic signals belong DNA methylation or histones modification associated with a change in the chromatin structure and the consequent transcription machine accessibility on the gene promoter, although non-histone proteins also tightly associated with chromatin could be involved." https://lnkd.in/daR66WW View in LinkedIn

SUBSET TRANS PATH. "In contrast, trans epigenetic signals are maintained by soluble molecules such as transcription factors or small RNAs (sRNAs) acting in feedback loops of self regulation of own expression level. Recently it has been argued that prions could also represent a kind of epigenetic inheritance/paramutation-like phenomenon not based on nucleic acid but on the protein folding, resulting in different activity." https://lnkd.in/daR66WW View in LinkedIn

FUNCTION. "Several hypotheses regarding the functions of paramutation have been formulated, for example: the involvement in physiological systems evolved to control the expansion of sequences in the genome such as transposons and viruses able to expand in the genome across the generations, to regulate gene expression in polyploids, a function in inbreeding depression and in the corresponding hybrid vigor." https://lnkd.in/daR66WW View in LinkedIn

PARADIGM SHIFT. "The past few years have seen a paradigm shift in that the absoluteness of maternal organelle transmission is increasingly challenged." https://lnkd.in/d34vWHz View in LinkedIn

DOMINANT MATERNAL PATH. "Although not universal, maternal inheritance is the predominant mode of organelle transmission in all eukaryotic kingdoms." https://lnkd.in/d34vWHz View in LinkedIn

CYTONUCLEAR CONFLICTS. "The most frequently expressed explanation for the evolution of uniparental organelle inheritance is the avoidance of cytonuclear conflicts." https://lnkd.in/d34vWHz View in LinkedIn

LACKING EXPLANATION. "The available models of organelle inheritance fail to explain why the uniparentally paternal mode of organelle inheritance is rare and why “killing one's own (paternal) cytoplasm” occurs." https://lnkd.in/d34vWHz View in LinkedIn

ROOT QUESTION. "The current theoretical problem connected with organelle inheritance is not its sex linkage per se, but rather the dominance of the maternal over the paternal mode and in many cases its control by the paternal gamete." https://lnkd.in/d34vWHz View in LinkedIn

GREAT DIVERSITY. "Organelle genomes of plants and animals as well as those of unicellular and multicellular eukaryotes differ greatly in genome organization, coding capacity, copy number per cell and mutation rate, as do cell and gamete sizes and ecological niches." https://lnkd.in/d34vWHz View in LinkedIn