“The Development of the Ideas of Scholars of Previous Generations Will Be the Best Monument for Them”: In Memory of Leonid Teodorovich Yablonsky (1950–2016)

Research objectives: To consider the creative path and main views of L.T. Yablonsky, as well as his influence on ideas about the ethnic history of the Golden Horde population and theoretical problems of ethnogenesis. Research materials: The authors of the article were based on numerous publications by L.T. Yablonsky, as well as personal impressions from meetings with the researcher on expeditions and at academic conferences. Results and novelty of the research: The authors consider the formation of L.T. Yablonsky as a unique specialist who combined archaeological training and professional study of physical anthropology. This allowed him to draw important conclusions about the formation of the Golden Horde population. Later, he resorted to this method to study the early nomads of the Aral Sea region and the South Urals. His works became an event in the research field, since they positively differed from others not only by an interdisciplinary approach to the problem under study – at the junction of archaeology and ethnogenetics – but also by the wide use of anthropological materials. Prior to these works, all information about the population of the Jochid ulus was fragmentary and unsystematic, and he was the very researcher who first connected the data of paleoanthropology and the analysis of the burial rite in medieval burial grounds. He proved the fact that the Golden Horde population consisted of mixed population groups, and identified those population groups that, in his opinion, came from Central Asia. L.T. Yablonsky attached great importance to the methodology of research on ethnogenesis and ethnic history. He advocated an integrated scientific approach to their study and emphasized the huge role of paleoanthropology and archaeology in solving ethnogenetic problems. In his opinion, the rapid divergence of various scientific disciplines – ethnology, archaeology, physical anthropology, and genetics – was the main problem that hindered the development of scientific ethnogenetic research. L.T. Yablonsky, therefore, believed that expanding comprehensive research would help solve this problem.

Equus roundworms (Parascaris univalens) are undergoing rapid divergence due to host and environment factors

Background The evolution of parasites is often directly affected by the host's environment. Studies on the evolution of the same parasites in different hosts are extremely attractive and highly relevant to our understanding of divergence and speciation. Methods Here we performed whole genome sequencing of Parascaris univalens from different Equus hosts (horses, zebras and donkeys). Phylogenetic and selection analysis was performed to study the divergence and adaptability of P. univalens. Results At the genetic level, multiple lines of evidence support that P. univalens were mainly separated into two clades (Horse-derived and Zebra & Donkey-derived). This divergence began at 300-1000 years ago, and we found that most of the key enzymes related to glycolysis were under strong positive selection in zebra & donkey-derived roundworms, but lipid related metabolism system was under positive selection in the horse-derived roundworms, indicating that the adaptive evolution of metabolism may drive the divergence in past few centuries. In addition, we found that some drug-related genes have a significantly higher degree of selection in different populations. Conclusions This work reports evidence that the host’s diet drives the divergence of roundworms for the first time, and also supports that divergence is a continuous and dynamic process, and continuous monitoring of the effects of differences in nutritional and drug history on rapid evolution of roundworms are conducive to further understanding host-parasite interactions.

Graph-based fusion of magnetometer and learned-based inertial odometry

<div>The 3D position estimation of pedestrians is a vital problem in the development of virtual reality, augmented reality, and the internet of things. The learning-based inertial odometry is a very potential auxiliary method of pedestrian positioning due to its low position drift and immunity to external environmental influences. However, in many cases, the drift error of the heading is still the main factor that causes the rapid divergence of the position estimated by the learning based inertial odometry. This paper proposed a graph optimization-based estimation method to fusing learned based inertial odometry and magnetometer measurements for obtaining lower drift position. The proposed algorithm does not need to calibrate the magnetometer bias, and effectively resist the influence of magnetic interference in the indoor environment, and can provide a very reliable absolute magnetic heading correction. Test results show that the proposed method can obtain better positioning performance than other methods using calibrated magnetometer observations.</div>

Graph-based fusion of magnetometer and learned-based inertial odometry

<div>The 3D position estimation of pedestrians is a vital problem in the development of virtual reality, augmented reality, and the internet of things. The learning-based inertial odometry is a very potential auxiliary method of pedestrian positioning due to its low position drift and immunity to external environmental influences. However, in many cases, the drift error of the heading is still the main factor that causes the rapid divergence of the position estimated by the learning based inertial odometry. This paper proposed a graph optimization-based estimation method to fusing learned based inertial odometry and magnetometer measurements for obtaining lower drift position. The proposed algorithm does not need to calibrate the magnetometer bias, and effectively resist the influence of magnetic interference in the indoor environment, and can provide a very reliable absolute magnetic heading correction. Test results show that the proposed method can obtain better positioning performance than other methods using calibrated magnetometer observations.</div>

Evolution of a cytoplasmic determinant: evidence for the biochemical basis of functional evolution of the novel germ line regulator oskar

Germ line specification is essential in sexually reproducing organisms. Despite their critical role, the evolutionary history of the genes that specify animal germ cells is heterogeneous and dynamic. In many insects, the gene oskar is required for the specification of the germ line. However, the germ line role of oskar is thought to be a derived role resulting from co-option from an ancestral somatic role. To address how evolutionary changes in protein sequence could have led to changes in the function of Oskar protein that enabled it to regulate germ line specification, we searched for oskar orthologs in 1565 publicly available insect genomic and transcriptomic datasets. The earliest-diverging lineage in which we identified an oskar ortholog was the order Zygentoma (silverfish and firebrats), suggesting that oskar originated before the origin of winged insects. We noted some order-specific trends in oskar sequence evolution, including whole gene duplications, clade-specific losses, and rapid divergence. An alignment of all known 379 Oskar sequences revealed new highly conserved residues as candidates that promote dimerization of the LOTUS domain. Moreover, we identified regions of the OSK domain with conserved predicted RNA binding potential. Furthermore, we show that despite a low overall amino acid conservation, the LOTUS domain shows higher conservation of predicted secondary structure than the OSK domain. Finally, we suggest new key amino acids in the LOTUS domain that may be involved in the previously reported Oskar-Vasa physical interaction that is required for its germ line role.

Habitat fragmentation induces rapid divergence of migratory and isolated sticklebacks

The adaptive capacity of many organisms is seriously challenged by human-imposed environmental change, which currently happens at unprecedented rates and magnitudes. For migratory fish, habitat fragmentation is a major challenge that can compromise their survival and reproduction. Therefore, it is important to study if fish populations can adapt to such modifications of their habitat. Here, we study whether originally anadromous three-spined stickleback populations (Gasterosteus aculeatus; "migrants") changed in behavior and morphology in response to human-induced isolation. We made use of a natural field-experiment, where the construction of pumping stations and sluices in the 1970s unintendedly created replicates of land-locked stickleback populations ("resident") in the Netherlands. For two years, we systematically tested populations of residents and migrants for differences in morphology and behavioral traits (activity, aggressiveness, exploration, boldness and shoaling) in lab-based assays. We detected differences between migrant and resident populations in virtually all phenotypic traits studied: compared to the ancestral migrants, residents were smaller in size, had fewer and smaller plates and were significantly more active, aggressive, exploratory and bolder and shoaled less. Despite large ecological differences between 2018 and 2019, results were largely consistent across the two years. Our study shows that human-induced environmental change has led to the rapid and consistent morphological and behavioral divergence of stickleback populations in about 50 generations. Such changes may be adaptive but this remains to be tested.

A widely diverged locus involved in locomotor adaptation in Heliconius butterflies

Heliconius butterflies have undergone adaptive radiation and therefore serve as an excellent system for exploring the continuum of speciation and adaptive evolution. However, there is a long-lasting paradox between their convergent mimetic wing patterns and rapid divergence in speciation. Here, we characterize a locus that consistently displays high divergence among Heliconius butterflies and acts as an introgression hotspot. We further show that this locus contains multiple genes related to locomotion and conserved in Lepidoptera. In light of these findings, we consider that locomotion traits may be under selection, and if these are heritable traits that are selected for, then they might act as species barriers.

Diversity begets diversity through shared adaptive genetic variation: discovery of a cryptic wide-mouthed scale-eater

Adaptive radiations involve astounding bursts of phenotypic, ecological, and species diversity. However, the microevolutionary processes that underlie the origins of these bursts are still poorly understood. We report the discovery of a cryptic intermediate wide-mouth scale-eating ecomorph in a recent radiation of Cyprinodon pupfishes which provides crucial information about the evolutionary and ecological transition from a widespread algae-eating generalist to a novel microendemic scale-eating specialist. We first show that this ecomorph occurs in sympatry with generalist C. variegatus and scale-eating specialist C. desquamator across several hypersaline lakes on San Salvador Island, Bahamas, but is genetically differentiated, morphologically distinct when reared in a common garden, and sometimes consumes scales. We then compared the timing of selective sweeps on shared and unique adaptive variants in both scale-eating species to characterize the evolutionary path to scale-eating. We predicted that adaptation to the intermediate wide-mouth scale-eating niche aided in the rapid divergence of the more specialized scale-eater C. desquamator. Therefore, selection for shared adaptive variants would occur first in wide-mouth. Contrary to our prediction, four of the six sets of shared adaptive alleles in both scale-eating species swept significantly earlier in C. desquamator. Adaptive introgression from the specialist into the wide-mouth ancestor may have resulted in parallel evolution of their dietary niche. Conversely, no adaptive alleles for scale-eating were reused in a third sympatric specialist C. brontotheriodes, despite sharing 9% of hard selective sweeps. Our work provides a microevolutionary framework for investigating how diversity begets diversity during adaptive radiation.

Dating Alphaproteobacteria evolution with eukaryotic fossils

Elucidating the timescale of the evolution of Alphaproteobacteria, one of the most prevalent microbial lineages in marine and terrestrial ecosystems, is key to testing hypotheses on their co-evolution with eukaryotic hosts and Earth’s systems, which, however, is largely limited by the scarcity of bacterial fossils. Here, we incorporate eukaryotic fossils to date the divergence times of Alphaproteobacteria, based on the mitochondrial endosymbiosis that mitochondria evolved from an alphaproteobacterial lineage. We estimate that Alphaproteobacteria arose ~1900 million years (Ma) ago, followed by rapid divergence of their major clades. We show that the origin of Rickettsiales, an order of obligate intracellular bacteria whose hosts are mostly animals, predates the emergence of animals for ~700 Ma but coincides with that of eukaryotes. This, together with reconstruction of ancestral hosts, strongly suggests that early Rickettsiales lineages had established previously underappreciated interactions with unicellular eukaryotes. Moreover, the mitochondria-based approach displays higher robustness to uncertainties in calibrations compared with the traditional strategy using cyanobacterial fossils. Further, our analyses imply the potential of dating the (bacterial) tree of life based on endosymbiosis events, and suggest that previous applications using divergence times of the modern hosts of symbiotic bacteria to date bacterial evolution might need to be revisited.