In the genomes of complex organisms, genes make up only a small percentage, often just 1–2%. Everything else was long described as the “dark matter of the genome,” a part about which little was known, so it was assumed to have no particular function. Today we know that assumption was too hasty, in that “dark matter” there are repetitive DNA sequences, such as satellite DNA and mobile genetic elements, that are key to genome organization and evolution.
These sequences build chromosome regions that are important for proper cell division and for protecting chromosome ends, they are linked to rearrangements in the genome, they can influence gene activity, and indirectly, the behavior of organisms. The genome is therefore not just a list of genes, but a complex architecture in which repeats play a major role.
When one answer opens five new questions
At the beginning of her career, what surprised Eva most was how science constantly broadens the horizon, each experiment answers one question, and at the same time opens a series of new ones. She was especially intrigued by the connection between tandemly repeated sequences, such as satellite DNA, and dispersed repeating mobile elements, and by the complex networks and hybrid structures they form together in the genome.
Two projects, two stories, the same focus
She currently leads two scientific projects. The first focuses on bivalves, economically important because of aquaculture, and ecologically relevant because of invasive species. The project investigates how repetitive sequences influence the molecular evolution and genome architecture of bivalves, including comparisons of the genome’s “dark matter” in a native and an invasive species. Analyses of repetitive sequences in oysters have already revealed new organizational patterns and interesting exceptions to the usual concepts in the biology of repetitive DNA.
The second project deals with the mealworm beetle, Tenebrio molitor, a species that is both a pest in grain storage facilities and an organism with useful properties, from antifreeze proteins, to the ability to break down plastic, to antimicrobial traits. Eva studies it because of its exceptionally high proportion of satellite DNA, as much as 50% of the genome. The goal is to discover where these sequences are in the genome, when they are active, how old they are, how they behave across different developmental stages, and whether they are also present in related species.
What exactly does the project leader do?
As the leader of both projects, Eva designs and directs the research, takes part in experimental and bioinformatics work, analyzes data and interprets results, monitors progress toward objectives, mentors early career researchers, disseminates results, and writes scientific papers.
Why does it matter?
These are fundamental biological studies that generate new knowledge, knowledge that is first published in scientific journals and, over time, in books and textbooks. Each new study uncovers additional roles of the genome’s “dark matter,” increasing its perceived importance, and helping us build a more complete picture of how genomes function and evolve. In addition, studying bivalves and the mealworm yields insights that may be valuable for ecology, biotechnology, and the economy, and an important long term benefit is education, and the training of young scientists through work on these projects.
