BMC Seminar - Centromeres, Polyploidy, and the Reshaping of Genomes

Date: Thursday 4th of August at 12:30 in Árnagarður room 306

Title: Centromeres, Polyploidy, and the Reshaping of Genomes: Insights from Plants to Cancer

Speaker: Victor A. Albert, Assistant Professor, Department of Biology, University of Iceland 

Abstract: Comparative studies of plant genomes and cancer cells reveal striking parallels in chromosome behavior, from centromere organization to the consequences of polyploidy and large-scale rearrangements. My research has impact on these convergences through the use of long-read DNA sequencing, which resolves highly repetitive regions that short-read assemblies often misrepresent. This approach has been especially critical for centromeres, which are composed of tracts of tandem repeat units. In monocentric chromosomes, centromeric repeats cluster at a single locus, whereas in holocentric systems they are distributed as numerous small foci along the entire chromosome. We have investigated an evolutionary shift to holocentricity between two carnivorous sundew species (Drosera; sóldögg in Icelandic) that are extremely close relatives while having radically different chromosomal architectures: one is holocentric and hexaploid, whereas the other is monocentric and dodecaploid. Holocentricity confers tolerance to repeated fusions and fissions, paralleling polycentric chromosomes in some cancers. Broken chromosomes can continue to segregate after their fragmentation, unlike monocentric systems, where these breaks often cause severe genetic losses. Likewise, our research on complex polyploidy highlights another powerful convergence: cancer genomes often undergo whole-genome duplications. While mammals cannot naturally tolerate polyploidy, plants have undergone it repeatedly. Sundews therefore provide a natural system for comparing the consequences of centromere repatterning and genome doubling across very different biological contexts. Extending beyond sundews, we also explore the dynamics of large duplicated and translocated genomic blocks in other species. In our work, these block-wise rearrangements have carried biosynthetic gene clusters that lead to generation of medically relevant metabolites, whereas in humans, similar restructuring is frequently linked to disease phenotypes. Together, these studies illustrate how processes that destabilize cancer genomes - centromere shifts, genome doubling, and block translocation - can act as adaptive forces in plants, driving diversification and functional innovation.

Biography: Victor A. Albert is a comparative genomicist who recently joined the Department of Biology at the University of Iceland, after many years at the University at Buffalo (SUNY). His research emphasizes genome structure - especially centromere biology, polyploidy, and chromosomal organization - and how these features shape genome function. By examining variation in centromere form and large-scale chromosomal restructuring, his studies, mostly on plants, have provided insights into evolutionary diversification while also drawing connections to cancer biology, where comparable alterations in genome organization and polyploidy are hallmarks of tumorigenesis. Albert has also advanced the genomics of specialized metabolism with medical relevance. He co-led genomic analyses of Rauvolfia, which produces reserpine, an important antihypertensive alkaloid in the same monoterpene indole alkaloid family as potent anticancer drugs. He identified the genomic context of caffeine biosynthesis in coffee, showing that it arose independently from similar pathways in tea and cacao. Beyond these systems, Albert has co-led genome projects on avocado, birch, and lychee, expanding resources for crop biology and comparative genomics. His group has also investigated unusual genome architectures in carnivorous plants such as Utricularia (bladderworts; blöðrujurt in Icelandic) and Drosera (sundews; sóldögg). Work on Utricularia showed that extreme genome size reduction is linked to runaway DNA deletion and suppression of transposable element proliferation, consistent with a “polyploid buffering” hypothesis in which repeated whole-genome duplications provide resilience against gene loss. In Drosera, his research has revealed striking contrasts in centromere architectures, with some species showing transitions to holocentricity, offering a rare perspective on divergent centromere structures in close relatives. His research has appeared in Nature, Science, Nature Genetics, and PNAS.