[
International Worm Meeting,
2021]
Essential genes can be defined as the ones which are crucial for organism survival and reproduction. They are responsible for the functions which are most important for the organism fitness pointing out to the most fundamental biological processes. They play a significant role in evolution, as their loss leads to the organism death or inability to reproduce. But this simple definition is not sufficient as gene essentiality is context dependent and vary with genetic and environmental background. So, the same mutation might lead to cell/organism death or severe sickness in some but not all genetic and environmental contexts. Most studies on gene essentiality were done in one genetic background. That means, that many genes essential in other genetic contexts were probably unidentified. Although the number of studies analysing gene essentiality in different genetic and environmental contexts is increasing, they are mainly done with unicellular organisms or cell lines. There is noticeable underrepresentation of such studies in multicellular, whole organisms. In this study we aim to uncover context dependence of gene essentiality in model multicellular organism, Caenorhabditis elegans. We show how essentiality of genes is changing depending on genetic context by using three different wild type worm isolates: N2, LKC34, and MY16. Our set of targeted genes included 100 essential and 200 nonessential genes based on DEG database (www.essentialgene.org). Each query gene was inactivated by RNA interference (RNAi) and mutant fitness was measured quantitatively as the rate of bacterial food consumption. We identified new essential genes indispensable in i) all three (22), ii) two (10), and iii) only one (11) genetic background. From previously identified N2 essential genes, we confirmed their essentiality in two additional backgrounds (68 genes), or one of them (9 cases). As we see even in a study encompassing only three strains, and 300 genes, we can observe substantial context dependence of gene essentiality. This have very important practical consequences as well. When working on gene therapies researchers should consider that different strategies might be needed depending on genetic background in which they will be used.