Geographical Races Research Articles

Микробные ассоциации географических рас Hippophae rhamnoides L. в условиях разных почвенно-климатических зон

Облепиху крушиновидную ( Hippоphae rhamnoides L.) применяют в агролесомелиорации эродированных земель и озеленении населенных пунктов, а также при создании промышленных плантаций. Облепиха относится к актиноризным растениям, у которых формируются бактериосимбиотрофические отношения корневой системы и почвенных микроорганизмов, представителей порядка актиномицетов (Actinomycetales) рода Frankia . В условиях разных почвенно-климатических зон в местах роста облепихи происходит селектирование ассоциативной микробиоты. Показаны различия в составе и структуре разных микробиомов в корневой зоне облепихи для прибалтийского, сибирского, среднеазиатского и кавказского климатипов. Определены факторы (эдафические и биологические условия), лимитирующие рост облепихи в разных почвенно-климатических условиях. Показано, что в искусственных насаждениях облепихи создаются благоприятные условия для накопления и роста почвенных патогенов из рода Alternaria , Fusarium , Rhizopus , а также большого набора плесневых грибов из рода Aspergillus , Clonostachys , Cunninghamella , Mucor , Humicola , Penicillium , Paecilomyces. Sea buckthorn ( Hippophae rhamnoides L.) is used in agroforestry of eroded lands and landscaping of settlements, as well as in the creation of industrial plantations. Sea buckthorn belongs to actinorhizal plants that form bacteriosymbiotrophic relationships between the root system and soil microorganisms, representatives of the actinomycetesorder ( Actinomycetales ) of the genus Frankia . Under the conditions of different soil-climatic zones in the places of sea buckthorn growth, the associative microbiota is selected. Differences in the composition and structure of different microbiomes in the root zone of sea buckthorn for the Baltic, Siberian, Central Asian and Caucasian climatypes are shown. The factors (edaphic and biological conditions) limiting the growth of sea buckthorn in different soil and climatic conditions were determined. It has been shown that favorable conditions are created in artificial plantations of sea buckthorn for the accumulation and growth of soil pathogens from the genus Alternaria , Fusarium , Rhizopus , as well as a large set of mold fungi from the genus Aspergillus , Clonostachys , Cunninghamella , Mucor , Humicola , Penicillium , Paecilomyces.

Unsuitability of the gall‐inducing fly Eutreta xanthochaeta for biological control of Lantana camara in presence of other native hosts in nature

AbstractThe biological control of weeds requires the successful introduction and establishment of natural enemies into other regions, to reduce population densities of target species. Potential biocontrol agents are sought in the native region of target weed and should be highly specialized. The gall‐inducing fly Eutreta xanthochaeta Aldrich (Diptera: Tephritidae) is native to Mexico and has been brought into other regions of the world – such as Hawaii (USA), South Africa, and Australia – for the biological control of Lantana camara L. (Verbanaceae), although this not always proved to be successful. Here we investigate the trophic interactions of this fly species with two host plants inhabiting in sympatry, L. camara and Lippia myriocephala Schltdl. & Cham. (Verbenaceae), evaluating its preference through infestation rates, the gall distribution in the plant architecture, as well as the indirect impact upon production of inflorescences affecting the reproductive capacity of the plants. We found that the fly was not monophagous in its native range, and under natural conditions it preferred the wild host L. myriocephala in the presence of L. camara. Moreover, we found that gall formation was linked to changes in the host architecture along with the potential for reproduction, leading to increased terminal buds and a reduction in the inflorescences produced on the twigs where galls develop. Lantana camara consists of both horticultural hybrids and wild varieties resulting in unresolved taxonomic ambiguities. Hence, there may be adaptive limitations of this fly to distinct geographic races or climatic conditions in the various regions, which needs further investigation.

The Importance of Contact Zones for Distinguishing Interspecific from Intraspecific Geographic Variation.

With limited sampling, geographic variation within a single species can be difficult to distinguish from interspecific variation, confounding our ability to draw accurate species boundaries. We argue that thorough sampling and analysis of contact zones between putative taxa can determine if assortative mating or selection against hybrids exists (supporting the presence of two distinct species), or alternatively if mating is random among genotypes and admixture among adjacent populations is gradual and continuous (supporting geographic variation within a single species). Here, we test two alternative hypotheses for two pairs of named taxa at contact zones within the American milksnake (Lampropeltis triangulum) complex. A prior morphological analysis found areas of gradual intergradation among named taxa, and concluded that the taxa represented geographical races of a single polytypic species. In contrast, a subsequent analysis of gene sequence data, but with limited sampling near the contact zones, hypothesized distinct boundaries between species at the contact zones. At the contact zone between proposed species L. triangulum and Lampropeltis gentilis, we examined a $\sim$700 km-wide transect across the states of Kansas and Missouri, with thorough sampling and reduced-representation genomic-level sequencing, to test the two opposing taxonomic hypotheses. Our transect analyses included examinations of population structure, fixed differences, cline-fitting, and an admixture index analysis. These analyses all supported a gradual and continuous geographic cline across a broad intergrade zone between two geographic forms of L. triangulum, thus providing strong support for a single species in this region (and no support for the recognition of L. gentilis as a distinct species). At a second contact zone between proposed species L. triangulum and Lampropeltis elapsoides (but variously treated as species or subspecies by different researchers) in Kentucky and Tennessee, we re-evaluated morphological data. In this case, the contact zone analysis indicated sympatry and reproductive isolation of the two taxa, and thus strongly supported L. triangulum and L. elapsoides as distinct species. We conclude that detailed studies of contact zones, based on either genetic or morphological data, are essential for distinguishing intraspecific from interspecific variation in the case of widely and continuously distributed taxa. [Contact zones; speciation; species concepts; species delimitation; taxonomy.].

Resolved and Redeemed: A New Fleck to the Evolutionary Divergence in the Genus Scomberomorus Lacepède, 1801 (Scombridae) With Cryptic Speciation

The genus Scomberomorus, with 18 nominal species, sustains a significant heterogeneous fishery throughout its range. The sole molecular systematic study of this genus concerned the species group S. regalis, which contains the new world taxa. The species diversity of Scomberomorus in the northern Indian Ocean has not been studied at the molecular level, often leading to misidentifications. Here, novel genetic data are provided that reconfigure species boundaries from the region. We used single and multilocus data (eight mitochondrial and three nuclear genes) to infer phylogenetic relationships, species delimitation, and the resurrection of a time-calibrated phylogenetic tree. Our aim was also to verify the hypothesis of geographical races in S. guttatus predicated on variable vertebral counts. Interestingly, all species delimitation analyses have recovered another highly cryptic species in the nominal S. guttatus previously believed to have an Indo-Pacific distribution. Scomberomorus guttatus (Bloch and Schneider, 1801) in the sensu stricto, is redeemed from its type locality based on genetic data and preliminary morphomeristic investigations and has a restricted distribution in the Bay of Bengal. The cryptic species Scomberomorus aff. guttatus which exhibits >10% genetic divergence from S. guttatus is resurrected here from the synonymy of the latter as Scomberomorus leopardus (Shaw, 1803). Widespread in the Indo-Pacific, this species contains two major molecular operational taxonomic units (MOTUs) with a divergence threshold of over 2% between them. Our analysis suggests that vertebral counts must be coupled with other features to identify the species/lineages in the nominal S. guttatus. The heterogeneity in the S. guttatus species group is discussed in relation to the ecological diversity of the region which facilitates larval recruitment and niche specialization. The results also revealed two allopatric putative species in S. commerson, found primarily in the Pacific and Indian Oceans. This study added genetic data from S. lineolatus and S. koreanus, not previously represented in the sequence repositories. Estimation of divergence time indicated that the Indo-West Pacific species group undergoes multiple diversification events besides the recent splits detected within S. leopardus.

Транзитивні таксономічні системи (TTS) та видоутворення в процесі динаміки ареалів

The system of views on the structure of geographic ranges of species (superspecies) and their dynamics as one of the key features of species and the basis of taxonomic differentiation and evolution is considered. The mechanisms leading to the formation of new taxa in several ways are analysed, including (1) the formation of transitive taxonomic systems (TTS), in which spatial differentiation leads to the formation of geographically differentiated races as ‘small’ species; (2) the formation of new geographical races in relation to the maternal species (plesions), distributed within the primary ranges; (3) the formation of sibling species as a result of dispersal of one ‘small’ species into the range of the sister species. All such groups of ‘small’ species coexist in time and illustrate models that correspond to E. E. Reclus’s view of ‘geography is history in space.’ A number of illustrative cases discovered in the analysis of the taxonomic heterogeneity of different groups of mammals of the European fauna or the Palaearctic as a whole are considered. In particular, there were analysed the features of spatial-taxonomic differentiation in allospecies complexes that fall under the definition of TTS, in which the distribution of allospecies reflects the patterns of spatial differentiation of the ‘large’ species over time (phylogeographic patterns). Similar complexes have been demonstrated on the example of ground squirrels, birch mice, and wood mice. The formation of TTS, as well as new forms as a result of invasions into new ranges (or dispersal to ranges of adjacent forms) is considered within the amplificative species concept (ASCo), according to which specialization occurs not as a result of reduction of both the range and variability (classic models with founder effect or bottleneck), but in the phase of flourishing of the species, in particular when new populations emerge outside the initial natural ranges due to expansions or invasions. The invasive model of speciation was formed based on this idea, and a partial example of it is the formation of sympatric pairs of sibling species formed as a result of secondary sympatry, i.e. expansion. Examples from other groups, in particular regarding the formation of compilospecies and other variants of hybridogenic taxa provoked by introductions or invasions, are considered. All this is viewed through the prism of the concept of speciesness as the level of achievement of evolutionary separateness.

The Landscape of Genetic Alterations Stratified Prognosis in Oriental Pancreatic Cancer Patients.

BackgroundPancreatic cancer is a life-threatening malignant disease with significant diversity among geographic regions and races leading to distinct carcinogenesis and prognosis. Previous studies mainly focused on Western patients, while the genomic landscape of Oriental patients, especially Chinese, remained less investigated.MethodsA total of 408 pancreatic cancer patients were enrolled. A panel containing 436 cancer-related genes was used to detect genetic alterations in tumor samples.ResultsWe profiled the genomic alteration landscape of pancreatic duct adenocarcinoma (PDAC), intraductal papillary mucinous neoplasm (IPMN), periampullary carcinoma (PVC), and solid-pseudopapillary tumor (SPT). Comparison with a public database revealed specific gene mutations in Oriental PDAC patients including higher mutation rates of DNA damage repair-related genes. Analysis of mutational signatures showed potential heterogenous carcinogenic factors caused by diabetes mellitus. KRAS mutation, especially KRAS G12D mutation, was associated with poor survival, while patients not harboring the 17 significant copy number variations (CNVs) had a better prognosis. We further identified multiple correlations between clinicopathologic variables and genetic mutations, as well as CNVs. Finally, by network-based stratification, three classes of PDAC patients were robustly clustered. Among these, class 1 (characterized by the Fanconi anemia pathway) achieved the best outcome, while class 2 (involved in the platinum drug resistance pathway) suffered from the worst prognosis.ConclusionsIn this study, we reported for the first time the genetic alteration landscape of Oriental PDAC patients identifying many Oriental-specific alterations. The relationship between genetic alterations and clinicopathological factors as well as prognosis demonstrated important genomic impact on tumor biology. This study will help to optimize clinical treatment of Oriental PDAC patients and improve their survival.

Standing variation rather than recent adaptive introgression probably underlies differentiation of the texanus subspecies of Helianthus annuus

The origins of geographic races in wide-ranging species are poorly understood. In Texas, the texanus subspecies of Helianthus annuus has long been thought to have acquired its defining phenotypic traits via introgression from a local congener, H. debilis, but previous tests of this hypothesis were inconclusive. Here we explore the origins of H. a. texanus using whole genome sequencing data from across the entire range of H. annuus and possible donor species, as well as phenotypic data from a common garden study. We find that although it is morphologically convergent with H. debilis, H. a. texanus has conflicting signals of introgression. Genome wide tests (Patterson's D and TreeMix) only find evidence of introgression from H. argophyllus (sister species to H. annuus and also sympatric), but not H. debilis, with the exception of one individual of 109 analysed. We further scanned the genome for localized signals of introgression using PCAdmix and found minimal but non-zero introgression from H. debilis and significant introgression from H. argophyllus in some populations. Given the paucity of introgression from H. debilis, we argue that the morphological convergence observed in Texas is likely from standing genetic variation. We also find that genomic differentiation in H. a. texanus is mostly driven by large segregating inversions, several of which have signatures of natural selection based on haplotype frequencies.

Чек-лист синтаксонов Российской Арктики: текущее состояние классификации растительности

Чек-лист синтаксонов Российской Арктики: текущее состояние классификации растительности

The Concept of Bird Species: Theory and Practice

As it has presently become evident, reproductive isolation can no longer be considered as the leading criterion for estimating the species limits, but it is still used for determining the status of the majority of morphs. The presence/absence of hybridization between individuals is not directly related to the degree of their evolutionary insularity. Hybridization can result in the origin of new morphs including those that have species status. The application of phylogenetic methods is justified in reconstructing the relation links within complex groups including the morphs of various evolutionary levels (from geographical races to “good” species), the relationships between which are exacerbated by hybridogenous polymorphism and/or the hybridization origins of their populations. Taking into account both new data and new conceptions, we suggest genuine interrelated definitions of concepts such as species, subspecies, and semispecies in birds. The definitions are based on two main criteria: biological, i.e., an evaluation of the reproductive relations of the particular morphs with each other, and phylogenetic, i.e., an evaluation of their evolutionary age and kinship. The main feature of a species as an evolutionary entity should be considered through its stability in time even when its reproductive isolation is periodically broken. Geographic intraspecies races show sustainable variations of different degrees, but they have no reproductive isolation; they breed upon contact and form intergradation zones. They are taxonomically denoted as subspecies. Descriptions of new subspecies are viable to the limits that reflect the species’ natural geographic structure to the fullest extent. For the young morphs that have reached the level of species insularity in the course of evolution, it seems appropriate to restore a semispecies category. Semispecies show significant morphological differences and distinguished ecological particularities, as a rule, but they are connected to closely related morphs by gene flows in contact zones. Distinguishing this category is not regulated by the International Code of Zoological Nomenclature and, as splitter tendencies prevail in modern systematics, semispecies are more often equated to species; i.e., they have binominal names. We propose to denote the attribution of a semispecies to a particular species group (superspecies) in parentheses between genus and species names. Thus, it would become possible to outline natural complexes and avoid a groundless increase in the taxonomic statuses of morphs in the stage of development. Representatives of distant phylogenetic lines (morphs that separated historically long ago) are not to be considered as semispecies even in the cases of their reproductive isolation being broken and a steady hybridization existing between them.

The Law of Homologous Series in Variation for Systematics

The article discusses the significance of Vavilov’s law of homologous series in variability for plant systematics. According to this law, the Linnean species was proposed to be considered as a dynamic system of ecological and geographical races—hereditary forms, all of them are variable across time and space under the influence of environmental factors and after mutations and recombination of alleles during hybridization in either nature or experiments. In nature, species can differ in many traits, but the spectrum of potential variability of morphological and physiological characters hidden in the genotype is almost the same in related species. Related genera and species differ only in a few significant characters (so called, radicals); they are the only taxonomically significant characters. Radicals and the genetic affinity of species can be revealed in experiments by disclosing the latent intraspecific phenotypic and genetic diversity of the species. The farther the species are from each other, the less overlap the variability spectra of their phenotypes and genotypes. It took time and the emergence of new effective approaches for assessing the genetic affinity of plants (such as karyosystematics, immunosystematics, GISH, and molecular phylogeny), to put at the service of plant taxonomy not just the study of morphological similarity but the study of characters of relatedness. The current stage of the study of parallel genotypic variability in plants is characterized by the fact that, as a result of advances in molecular phylogeny and comparative genomics, there is a real opportunity to study the phenomenon of morphologically indistinguishable but genetically heterogeneous (cryptic) species and to study the degree of genetic diversity and kinship of natural populations of morphologically polymorphic species with wide area of distribution.

Investigating the Natural Bee Space and Comb Cell Dimensions of an Ethiopian Honeybee Race (<i>Apis Mellifera Scutellata</i>) in Borana Zone, Southern Ethiopia

A study to determine bee space and comb cell dimensions for local honeybee race (Apis mellifera scutellata) was conducted in two districts of Borana zone, Oromia regional state, Southern part of Ethiopia during 2017. Data regarding bee space, worker bee comb cell dimensions, comb thickness and comb space were measured in traditional log hives using digital caliper. Comb length and comb width were measured and the number of worker bee cells per unit area were marked and counted from the combs. The collected data was fitted in GLM procedure of SAS version 9 to identify the effect of agro-ecology and comb type on the considered parameters. The race maintained an average 11.30±1.99mm bee space and 18.78±3.0mm comb thickness. The overall worker bee cell width and depth of the race were 4.65±0.30mm and 10.28±0.74mm respectively. It was observed that the race can construct a comb with an average of 44.80cm long and 20.51cm wide in their nest. The mean number of worker bee cells count per 100cm2 is 539.44 cells (ranging from 441-621). This finding shows variations in bee space (11.30mm), cell diameter (4.65mm) and cell depth measurements (10.28mm) from other similar studies in the other parts of the country. Based on the analyzed data, it is understood that ecological differences (climate, vegetation type, altitudes, etc.) between the midland and lowland has got significant variation in biological diversity of the honeybee races of the study area compared to the other zones of the region/ country. Thus, it is suggested that further study on these measurements is required as parameters for the honeybee geographical races of the zone and the surrounding areas to come to a reliable recommendation to use this specification in improved hive construction.

The objective existence of race

There are currently two very different concepts of race in terms of negation and identity. The emergence of these different perspectives of race is related to its definition. Scholars who deny the existence of human races regard different races as being different species in biology. However, the ethnic problem is an academic issue that can be discussed and the concept of race is still used widely in social life. Race should not be confused with racism. All modern humans on Earth are the same species. Races are human populations with common genetic traits. The concept of race is not a biological concept of race, but a geographic concept of race. After the birth of modern humans, they dispersed and migrated to different parts of the world. The environment in different regions determined the genetic variation of the migration branches of each population. Gradually, different geographical species of modern humans were formed. This is what we are talking about when we speak of race. The divisions of race do not depend on only one trait, but on the comprehensive consideration of multiple traits. The academic community uses macroscopic morphological indices, such as skin color, hair color, eye color, nose shape, lip shape, head shape, facial shape, skin texture, earwax type, and blood type, to describe and classify human races. Single-nucleotide polymorphisms and gene copy number polymorphisms contribute to the formation of different races. Through the measurement and observation of the head and face morphological index and stature of the Mongolian, Northern Han, and Dai populations, this study found significant differences in the head and face characteristics between North Asian, East Asian, and South Asian types. The North Asian-type ethnic groups were found to have taller stature, a wider head, a narrower nose, and a thinner lip, while South Asian-type ethnic groups were of shorter stature, with wider noses and thicker lips. The head and facial features of the East Asian-type ethnic groups are between the North and South Asian-type ethnic groups. Scholars may deny the existence of human races or that races are different species, but they cannot deny the existence of different modern geographical races or their obvious morphological differences. Since the differences between races are geographic, the genomic differences between individual races are naturally small; thus, 99.9% of the DNA sequences from different races are identical. However, this difference of about 0.1% of DNA sequences leads to the division of races. Although the speed of integration between ethnic groups is currently increasing, the differences in traits between different races are still obvious. The main racial characteristics have not disappeared and the differences between races will persist for a long time. This study proposes that the concept of race is outdated and does not actually conform to its objective status.

Taxonomic and functional responses of soil microbial communities to slag-based fertilizer amendment in rice cropping systems

The effective utilization of slag-based Silicon fertilizer (silicate fertilizer) in agriculture to improve crop productivity and to mitigate environmental consequences turns it into a high value added product in sustainable agriculture. Despite the integral role of soil microbiome in agricultural production and virtually all ecosystem processes, our understanding of the microbial role in ecosystem functions and agricultural productivity in response to the silicate fertilizer amendment is, however, elusive. In this study, using 16S rRNA gene and ITS amplicon illumina sequencing and a functional gene microarray, i.e., GeoChip 5, we report for the first time the responses of soil microbes and their functions to the silicate fertilizer amendment in two different geographic races of Oryza sativa var. Japonica (Japonica rice) and var. Indica (Indica rice). The silicate fertilizer significantly increased soil pH, photosynthesis rate, nutrient (i.e., C, Si, Fe, P) availability and crop productivity, but decreased N availability and CH4 and N2O emissions. Moreover, the silicate fertilizer application significantly altered soil bacterial and fungal community composition and increased abundance of functional genes involved in labile C degradation, C and N fixation, phosphorus utilization, CH4 oxidation, and metal detoxification, whereas those involve in CH4 production and denitrification were decreased. The changes in the taxonomic and functional structure of microbial communities by the silicate fertilizer were mostly regulated by soil pH, plant photosynthesis, and nutrient availability. This study provides novel insights into our understanding of microbial functional processes in response to the silicate fertilizer amendment in rice cropping systems and has important implications for sustainable rice production.

Современная популяционная структура европейского анчоуса Engraulis encrasicolus L. (Engraulidae: Pisces) в Чёрном и Азовском морях и история её формирования

Европейский анчоус, или хамса, Engraulis encrasicolus L. — один из наиболее массовых видов рыб в Азово-Черноморском бассейне. E. encrasicolus — политипический вид; в Чёрном и Азовском морях он представлен двумя внутривидовыми формами — черноморским анчоусом (E. encrasicolus ponticus Alex.) и азовским анчоусом (E. encrasicolus maeoticus Pusanov), таксономический статус которых остаётся до настоящего времени неясным. Актуальной задачей является оценка современной популяционной структуры E. encrasicolus и её возможных изменений под воздействием климатических и антропогенных факторов в целях разработки необходимых мер по предотвращению негативных последствий и сохранения ресурсного потенциала вида. Данная работа посвящена изучению современной популяционной структуры европейского анчоуса в Чёрном и Азовском морях и геологических и палеоклиматических условий её формирования, а также оценке возможных изменений с учётом реальных природных и антропогенных факторов риска. В основу работы положены результаты изучения внутривидовой морфобиологической, биохимической, генетической и экологической изменчивости E. encrasicolus, а также пространственных и репродуктивных взаимоотношений азовского и черноморского анчоуса. В историческом аспекте выполнен анализ литературных данных по проблеме внутривидовой неоднородности E. encrasicolus в Чёрном и Азовском морях, полученных отечественными и зарубежными авторами за 100-летний период (1913–2014); список публикаций включает более 40 наименований. В работе использованы также результаты собственных исследований. Систематизированы и обобщены сведения о границах репродуктивных ареалов черноморского и азовского анчоуса. Установлено, что их репродуктивные ареалы охватывают всю акваторию Чёрного и Азовского морей и перекрываются на всём пространстве. При отсутствии отдельных, пространственно обособленных репродуктивных ареалов и при наличии одновременного нереста принадлежность черноморского и азовского анчоуса к разным подвидам (географическим расам) исключается. Популяционный уровень различий между черноморской и азовской хамсой подтверждают результаты генетико-биохимических исследований: коэффициенты генетического сходства и генетического расстояния между ними составили 0,9983–0,9985 и 0,0015–0,0017 соответственно. Представлена геологическая история формирования популяционной структуры Engraulis encrasicolus. Современные азовский и черноморский анчоусы в прошлом были пространственно разобщены и вступили в контакт лишь вторично (после того как в процессе эволюции между ними возник ряд различий). Их изоляция произошла в миоцене (23,0–5,3 млн лет назад), в новообразованном, изолированном от океана Тетис Сарматском море. В результате возникли две географически обособленные и независимые группы анчоусов (западная и восточная), дальнейшее развитие которых происходило с разной скоростью. Более быстрые темпы эволюции западной группы привели к образованию более прогрессивных черноморского и средиземноморского анчоусов, а более низкие темпы эволюции восточной группы — к образованию более примитивного азовского анчоуса. Только в современную эпоху, после окончания последнего ледникового периода и восстановления связи Чёрного моря со Средиземным 7–5 тыс. лет назад, произошёл контакт между ними, который впоследствии сопровождался гибридизацией, то есть образованием зоны вторичной интерградации. В условиях интрогрессивной гибридизации в последние десятилетия, связанной с осолонением Азовского моря в результате хозяйственной деятельности человека, существует реальная угроза разрушения генофонда азовской хамсы и её «генетического поглощения» черноморской. Тем не менее генетическая идентичность азовского анчоуса до настоящего времени сохраняется. Это происходит прежде всего благодаря экологическим механизмам сезонной (выбор времени) и биотопической (выбор места) изоляции в репродуктивный период. Установлена определённая закономерность перераспределения самок в составе нерестового стада: доля самок азовского анчоуса уменьшается, доля самок черноморской хамсы увеличивается. Из этого следует, что популяции азовского и черноморского анчоуса являются «температурными» расами, адаптированными к разным репродуктивным температурным условиям: азовская — к более низким, черноморская — к более высоким. Кроме сезонной, установлена биотопическая изоляция черноморской и азовской хамсы. Черноморский анчоус предпочитает нереститься в открытых районах Чёрного моря при солёности воды выше 16 ‰: там его доля составляет 55–60 % (в прибрежных водах значение показателя не превышает 5–40 %). Азовский анчоус, напротив, в нерестовый период преобладает в прибрежных опреснённых водах с солёностью ниже 15 ‰: его доля здесь достигает 60–90 %.

Концепция вида у тополей (genus Populus L., Salicaceae) на примере представителей подрода Tacamahaca (Spach) Penjkovsky, произрастающих в России и сопредельных странах

Using the traditional research methods, based on the example of local and cultivated representatives of the Tacamahaca (Spach) Penjkovsky subgenus growing in Russia and neighboring countries, the concept of a species in poplars (genus Populus L., Salicaceae) has been developed. It is suggested that the sections of black poplars (Aigeiros Duby) and balsamic poplars (Tacamahaca Spach) in Eurasia form a single supraspecific system with a common gene pool, which is very similar to syngameon. The taxonomic species that make up such a system are different dynamic states of this system and exist in the equilibrium state between natural selection, which forms and preserves the specifics of each dynamic state, and gene flows from other taxonomic species. Such a system can also be considered as a large Linnaean species represented by many subspecies or even geographical and ecological races. The use of molecular genetic methods for the taxonomic species study in the Populus genus is difficult due to the powerful flow of genes between the species, since the species differ in a small number of genes responsible for adaptive characters. The sections of the subgenus Tacamahaca poplars are ecological. The combination of species in these sections is not so much about the unity of their origin, but about the common growing conditions: black poplars tend to grow in lowlands, while the balsamic poplars tend to grow in the mountains, with which the poplars’ diagnostic characters are associated. In nature, belonging to a certain section is more profitable than the intermediate state, but in cultivation and in the urban environment, the opposite situation is observed.

Polymorphic Sites in ITS1-5.8S rDNA-ITS2 Region in Hybridogenic Genus × Elyhordeum and Putative Interspecific Hybrids Elymus (Poaceae: Triticeae)

The genus Elymus L. is a complicated aggregate of ecological and geographical races, species, subspecies, varieties, and hybrids. We suggest that comparative analysis of intragenomic polymorphism of internal transcribed spacers ITS1 and ITS2 of 35S rRNA genes in the supposed hybrids and their possible “parents” can be one of the approaches to verification of hybrid origin of the samples collected in nature to confirm or reject the hypotheses about their possible “parents.” Polymorphic sites (PS) in ITS of 23 Elymus species, as well as in two supposed interspecific Elymus hybrids and in a supposed intergeneric hybrid between Elymus × Hordeum determined as × Elyhordeum sp., were analyzed in the work. We collected all hybrids in the Altai. There were 2 and 5 PS in two samples of E. dahuricus and 1 and 4 PS in two studied samples of E. schrenkianus in the ITS1-5.8S rDNA-ITS2 region. From 0 to 4 (modes 0 and 3) PS were detected in 32 samples relating to 21 tetraploid Elymus species. More PS (14) were found in the × Elyhordeum sp. sample. A large number of single nucleotide substitutions were found in 5.8S rRNA in × Elyhordeum. It was shown that about half of them do not change the secondary structure of the 5.8S rRNA molecule, so these molecules probably retain the ability to work as a component of large subunit of a ribosome. On the other hand, the absence or weakening of 5.8S rDNA homogenization in × Elyhordeum indirectly suggests that a significant part of 5.8S rDNA is not transcribed. Paradoxically, ITS sequences of × Elyhordeum sp. are less polymorphic than 5.8S rDNA. There are no ITS sequences derived from Hordeum among × Elyhordeum ITS sequenced by Sanger method. No traces of the H subgenome and a subgenome originating from Agropyron (P-subgenome) are seen in the Alt 10–278 plant genome (a chimera, combining the morphological traits of Elymus, Elytrigia, and Agropyron). In this plant, as well as in the supposed intersectional hybrid Alt 11–60 distinguished by a mosaic of the traits typical for the E. caninus × E. mutabilis species, only 4 and 5 PS, respectively, are detected when sequencing by Sanger method. The comparison of ITS sequences of the supposed Elymus Alt 10–278 hybrid and its probable “parents” demonstrates that one of the species of the Elymus macrourus kinship circle, as well as the Elytrigia geniculata, could be one of its ancestors. The comparison of the ITS sequence of the supposed parental species with ITS of Alt 11–60 samples and five PS of the supposed Alt 11–60 hybrid does not contradict the hypothesis that this is an intersectional hybrid of the first generation that emerged with the involvement of E. caninus and E. mutabilis common in the Altai.

Quantified reproductive isolation in Heliconius butterflies: Implications for introgression and hybrid speciation.

Heliconius butterflies have become a model for the study of speciation with gene flow. For adaptive introgression to take place, there must be incomplete barriers to gene exchange that allow interspecific hybridization and multiple generations of backcrossing. The recent publication of estimates of individual components of reproductive isolation between several species of butterflies in the Heliconius melpomene–H. cydno clade allowed us to calculate total reproductive isolation estimates for these species. According to these estimates, the butterflies are not as promiscuous as has been implied. Differences between species are maintained by intrinsic mechanisms, while reproductive isolation of geographical races within species is mainly due to allopatry. We discuss the implications of this strong isolation for basic aspects of the hybrid speciation with introgression hypothesis.

Evaluation of survival and growth of Picea abies (L.) H. Karst. and Picea obovata Ledeb. provenances in the north of Russia

Adaptation variability and ecological plasticity in the “genotype-environment” system of 22 provenances of Picea abies (Linnaeus) H. Karsten, Picea obovata (von Ledebour) and their introgressive hybrids growing within the Russian Plain were studied. Provenances grow in provenance trials located in the Arkhangelsk, Vologda Regions, and Komi Republic. For assessment of provenances in the “genotype-environment” system, the ranking method was used. Based on a complex ranking index (survival, diameter, height) two local areas of the most adaptive geographic races of P. abies, P. obovata and their hybrid forms were distinguished. In the south-western part of the Russian Plain the best provenances are represented by P. abies and related hybrids from Karelia, Vologda, Leningrad, and Pskov Regions. In the north-eastern part they are represented by P. obovata and its hybrids from the Komi Republic, Arkhangelsk, Sverdlovsk Regions. Provenances of local P. abies and related hybrid forms demonstrate high ecological plasticity on their growing in harsh climatic conditions of the north outside of the species distribution area.

Human Carcinogenesis: Toward a Unified Theory

If either chance or environmental exposure was the dominant carcinogen, cancer risk would increase continuously with age, but it doesn’t. For all cancers studied, risk exhibits three phases: 1) Low risk at young ages, followed by 2) an increase in risk to a maximum at some later age, followed by 3) a plateau or decline in risk at advanced ages. Only a genetically-determined discontinuous process can explain this pattern. We analyzed differences in risk between tissues of tumor origin and between geographic locations, genders, races, and ethnicities for clues. Our analyses suggest that normal tissue differentiation is safe, but inadequate. At some critical age, regeneration or dedifferentiation is required and this is an invitation to carcinogenesis. Upon reaching this critical age, risk varies with the size of a target, which may correspond to the number of regenerating or dedifferentiating stem cells. Cancer incidence rates were analyzed for melanoma and cancers of the mouth, esophagus, stomach, small intestine, colon, rectum, liver, pancreas, larynx, bronchus, breast, and kidney in populations distributed worldwide and within the United States in two time eras. Over all cancers, in all populations, and both eras, the difference in age-specific rates between ages 50 and 40, d50-40, correlated strongly with age-standardized rates. Differences in d50-40 correlated strongly with differences in age-standardized rates between genders, races, and ethnicities. We suggest that, for the cancers studied, the critical age occurs between 40 and 50. If environmental exposure or segregating genes was the dominant carcinogen, the rank order of cancer risk between tissues of tumor origin would vary from one geographic location to another, because environment and segregating genes vary between geographic locations. Such variation was observed between rank order in Japan and rank order in other countries, but not between rank orders in the other countries. We suspect, therefore, that environment or segregating genes play an important role in determining the difference in rank order of risk for the tissues of tumor origin between Japan and other countries. If chance or environmental exposure was the dominant carcinogen, cancer risk would correlate strongly between pairs of cancers across populations, but it doesn’t. Coefficients of risk between pairs of cancers are, typically, moderate at best. Only mouth, larynx, bronchus, and kidney show strong coefficients. By our measures, cancer risk from aging exceeds cancer risk from other-than-aging causes in all populations in both eras. We suspect that the aging risk is determined by genes that are common to all members of our species, and we suggest that inhibiting tissue injury and unnecessary growth will reduce cancer risk.

Life cycle and biology of Tristriata anatis (Digenea: Notocotylidae): morphological and molecular approaches.

Notocotylids are common digeneans parasitising birds and mammals. They have a two-host life cycle with cercariae encysting in the open. Particular life cycles remain unknown for majority of notocotylid species, including a common parasite of sea ducks Tristriata anatis. Here we resolve the life cycle of T. anatis by means of D2 LSU, ITS1 and CO1 DNA sequence analysis, showing that the first intermediate hosts for this species are periwinkles Littorina spp. Morphological descriptions of rediae and cercariae are provided for the first time, and we also supplement the existing morphological data on adults. Apart from differential diagnosis, we discuss some features of cercariae and rediae biology, geographical distribution and host range. Our molecular data confirm that genus Tristriata is monotypic and that T. anatis has circumpolar distribution. CO1 sequence analysis has shown that isolation exists between the Atlantic and Pacific populations of T. anatis, suggesting that there are geographical races. We suppose that their formation may be linked to the Last Ice Age events, when trans-Arctic bird migrations ceased and periwinkle ranges shrunk. These made transfer of parasites across the Arctic impossible, and it still has not resumed. We discuss the possible influence of host vagility and adults' lifespan on digeneans' potential for geographical colonisation.