IN A NUTSHELL
New and revolutionary
Like many other large events, SMBE meetings are almost obligatorily held in modern congress centers. Although this is a safe choice, all congress centers always provide the same rendering. The Urban Diffused Meeting (UDM) in Ferrara represents an exciting novelty which will make SMBE 2023 a remarkable and pioneering event.
Ferrara has a range of budget sleeping options including hostels, private rooms and campsites, which will facilitate attendance of students. In Italy! Ferrara is in the heart of Italy, close to the seaside and to iconic art and university cities such as Florence, Bologna, Venice, Padua and Rome.
The town is a great pedestrian renaissance city and part of the UNESCO world heritage: attendees will enjoy a spectacular view both during and between sessions.
UDM does not mean hazardous. Ferrara has a proven record of multiple successful UDM events, and the city structure is perfectly suited for it. Even in the case of (extremely rare for the season) rain. We will be “on the street” for the poster session, the coffee break, and when moving from one room to the other; coincidentally, this increases the general safety in a pandemic era. Read more on Covid Measures here.
Code of conduct
SMBE Annual Meeting prohibits all forms of discrimination and harassment, and requests that communications are respectful. Read more on the SMBE Meeting policies here.
Preliminary information on the program
The registration desk will open at 2.30 pm, July 23. The welcome reception is planned between 5 and 7 pm, followed by the first scientific talk, i.e. a keynote presentation, at 7 pm. The meeting will end at 1.30 pm, July 27, after the Awards Ceremony. The meeting will be held as a hybrid conference, but the speakers (keynote, invited, contributed) are encouraged to participate in person.
School of Earth Sciences
University of Bristol, UK
Telling evolutionary time
Integrating biological and geological timescales is crucial to establishing evolutionary rates, testing hypotheses on the interactions among evolving lineages and between the evolution of lineages and their environments. On this everyone can agree – though less so on how integration may be achieved. Nevertheless, after decades of adversarial interdisciplinary relations, it is encouraging that divergence time methods spawned from molecular biology are now routinely employed within palaeontology, establishing timescales for entirely extinct clades, from titanosaurs to trilobites. Hardliners remain on both sides, from those who believe that the fossil record should be read more or less literally, to advocates of allowing molecular data to have its say, unencumbered by fossil age constraints. Neither view is defensible since the fossil record alone is uninformative of evolutionary timescales, while molecular phylogenies tell only relative time without input from geological data. Combined, geological and molecular data can provide unforeseen insights, such as into the timing of gene and genome duplication, and their evolutionary consequences. Whether any of these timescales can be trusted depends on how they are put to work and they are certainly most powerful when employed to test prior hypotheses. Nevertheless, some confidence can be found in recent studies that have found mutual corroboration despite being based on fundamentally different data and methods. This is fortunate since, while many molecular clock studies are of groups that have a coherent fossil record against which to compare, the majority of clades now targeted by large scale sequencing initiatives lack a material fossil record.
Department of Ecology and Evolutionary Biology
Brown University, USA
Archaic and Modern Humans: An Evolutionary History of Recurrent Introgression and Natural Selection
In 2010, the first draft of the Neanderthal genome was published, followed by the profound revelation less than a year later that the DNA extracted from a finger bone in Denisova cave belonged to another distinct group of hominins. This group, now known as Denisovans, differed not only from anatomically modern humans but also from Neanderthals. The discovery of the Denisovans astonished researchers and revolutionized our understanding of the complexity of human evolution. Comparisons between Neanderthal, Denisovan and modern human genomes have provided compelling evidence of interbreeding between modern humans and archaic populations, revealing genetic admixture to be a critical factor in the shaping of genetic diversity among modern human populations. These results also inspired studies in non-human taxa which reveal that gene-flow between species was more common than previously appreciated. In light of these discoveries, my research has focused on studying and characterizing archaic introgression. I will discuss our past and recent work which reveals a history of multiple introgression events in modern human populations. Our latest work has uncovered evidence of how recent admixture impacted archaic ancestry in admixed populations from the Americas, providing essential insights into the genetic makeup of present-day communities. We have also detected genes with signatures of adaptive introgression, including one in particular, MUC19, which harbors a Denisovan-like haplotype at its highest frequency in admixed populations within the Americas. Further investigation into this gene's history of recurrent Denisovan admixture reveals the intricate ways that the introduction of variants through introgression has impacted the coding regions of the MUC19 gene. Our ongoing studies aim to develop new methods for analyzing admixed genomes and explore the impact of natural selection on introduced mutations. By advancing our understanding of the impact of admixture on genetic variation and evolution, we hope to contribute to a more comprehensive understanding of human history.
School of Life Sciences and Biodesign Center for Mechanisms of Evolution
Arizona State University, USA
Principles of Evolutionary Overdesign and Underperformance
For over a century, most biologists have been convinced that all aspects of biodiversity have been driven entirely by natural selection, with stochastic forces and mutation bias playing a minimal role. However, this is not the case at the molecular and cellular levels, where diverse traits scale with cell/organism size in ways that cannot be explained by optimization and/or speed vs. efficiency arguments. These include aspects of gene/genome architecture, intracellular error rates, the multimeric nature of proteins, swimming efficiencies, and maximum growth rates. Many prokaryotes may reside in population-genetic environments where the limits to selection are indeed dictated only by the constraints of cell biology. However, in the eukaryotic domain, larger organism size is typically associated with a reduction in effective population size (Ne), enabling the accumulation of very mildly deleterious mutations, which in turn induces coevolutionary side effects leading to more complex and less efficient phenotypes. This general conclusion is embodied in the drift-barrier hypothesis, which postulates that traits under persistent directional selection become stalled when further increments in improvement are thwarted by the power of random genetic drift. The latter is an inverse function of Ne. However, although estimates of Ne are typically derived from measures of standing variation at silent sites, this coalescent-based measure is not necessarily the Ne that governs phenotypic divergence. Moreover, recent work suggests that fluctuating selection may be as important a source of random stochasticity as gamete sampling, raising challenges as to how we quantify the role of noise in long-term evolutionary processes.
Kateryna D. Makova
Department of Biology and Center for Medical Genomics
Penn State University, USA
Telomere-to-telomere assemblies uncover secrets
of ape sex chromosomes
Evolution of ape sex chromosomes has remained enigmatic due to their highly repetitive nature and incomplete reference assemblies (particularly for the Y). Here we generated gapless, telomere-to-telomere assemblies of the X and Y chromosomes for all extant great ape species—chimpanzee, bonobo, gorilla, Bornean and Sumatran orangutans—and for an outgroup lesser ape, the siamang. To achieve this, we utilized state-of-the-art experimental and computational methods developed for deciphering the human T2T genome. These assemblies completely resolved ampliconic and satellite sequences, and allowed us to untangle ape sex chromosome evolution in unprecedented detail, leading to the following results. First, despite the divergence time of less than 18 million years, only 12-26% of non-human ape Y sequences align to the human Y, compared to 84-97% of non-human ape X sequences aligning to the human X. Second, depending on species, segmental duplications represent 21-53% of ape Y assemblies, compared to only 3.9-6.0% of ape X assemblies. Third, ampliconic sequences constitute 8.7-46% of ape Y assemblies, compared to only 0.15-1.1% of ape X assemblies. Most of such sequences on the Y are species-specific. Fourth, repeats account for 71-85% of ape Y assemblies compared to 57-64% of ape X assemblies. Our analyses indicate a remarkably dynamic evolution on the largely non-recombining Y chromosome, in contrast to a more stable evolution on the X chromosome. As the Y harbors regions important for fertility, our research will inform future studies of conservation genetics of non-human apes, all of which are endangered species.
Urban Diffused Meeting