scholarly journals Genetic Diversity of Autochthonous and Introduced Mollusk Species Cultivated in the Black Sea

2020 ◽  
pp. 26-30
Author(s):  
Е.Е. Слынько ◽  
Ю.В. Слынько
Keyword(s):  
Genetic Diversity ◽  
Black Sea ◽  
Crassostrea Gigas ◽  
Blue Mussel ◽  
Coi Gene ◽  
The Black Sea ◽  
Fish Hatchery ◽  
Coi Mtdna ◽  
The Pacific ◽  
Haplotypic Diversity

В настоящее время в мирихозяйствах Чёрного моря интенсивно выращиваются три вида двустворчатых моллюсков: тихоокеанская, или гигантская, устрица (Crassostrea gigas, (Thunberg, 1793)), интродуцированная из Дальневосточных морей, и два вида аборигенов – мидия (Mytillus galloprovincialis Lamarck, 1819) и средиземноморский гребешок (Flexopecten glaber (Linnaeus, 1758)). В отношении всех трёх видов выявляются две основные проблемы – точное установление таксономического разнообразия и тенденции в изменениях генетического разнообразия. Все проанализированные устрицы из черноморского питомника могут быть отнесены к виду Crassostrea gigas. В исследованных гаплотипах C. gigas по генам COI и 16S mtDNA обнаруживаются особи, специфические как для Атлантики, так и для Тихого океана. Среди гаплотипов COI mtDNA из питомника Института биологии южных морей (ИнБЮМ) выявлен ранее не известный гаплотип (MF663324), который является специфическим для Крымской популяции культивируемых C. gigas. Нуклеотидные последовательности фрагмента гена COI у исследуемых особей мидий Чёрного моря при соотношении с последовательностями M. edulis и M. trossulus формировали общую филогенетическую группу, отличающуюся от M. californuanus. Это позволяет уверенно отнести исследованных нами особей к комплексу «голубой мидии». Все изученные экземпляры гребешка из заливов озера Донузлав были идентифицированы по гену 16S как вид Flexopecten glaber и одновременно как вид F. proteus. Если экземпляры из Донузлава имели р-расстояние от F. glaber 0.2%, то от F. proteus – 0.1%. Это свидетельствует о том, что виды F. glaber и F. proteus входят в один таксономический комплекс и являются таксономическими синонимами. Таким образом, в Чёрном море обитают следующие виды двустворчатых моллюсков: Crassostrea gigas, Mytillus galloprovincialis и Flexopecten glaber. Все они характеризуются существенным падением гаплотипического разнообразия, а чужеродный вид – тихоокеанская устрица – ещё и снижением нуклеотидного разнообразия. Currently, three species of bivalved mollusks are intensively grown in the Black Sea world farms: Pacific or giant, oyster (Crassostrea gigas, (Thunberg, 1793)) introduced from the Far Eastern Seas and two autochthonous species – mussel (Mytillus galloprovincialis Lamarck, 1819) and Mediterranean fan shell (Flexopecten glaber (Linnaeus, 1758)). In relation to all three species two main problems are identified – the exact establishment of taxonomic diversity and the trends in changes in genetic diversity. All analyzed oysters from the Black Sea fish hatchery can be assigned to the species Crassostrea gigas. In the studied C. gigas haplotypes individuals specific to both the Atlantic and the Pacific Ocean are found by COI and 16S mtDNA genes. Among the haplotypes of COI mtDNA from the fish hatchery of the Institute of Biology of the Southern Seas (IBSS) a previously unknown haplotype (MF663324) was identified which is specific to the Crimean population of cultured C. gigas. Nucleotide sequences of a fragment of the COI gene in the individuals of Black Sea mussels under investigation at a ratio with the sequences M. edulis and M. trossulus formed a common phylogenetic group different from M. californuanus. This allows us to confidently attribute the studied individuals to the blue mussel complex. All studied scallop specimens from Lake Donuzlav bays were identified by the gene 16S as a species of Flexopecten glaber and simultaneously as a species of F. proteus. If the Donuzlav specimens had a p-distance from F. glaber of 0.2%, then from F. proteus – 0.1%. This indicates that the species F. glaber and F. proteus are part of the same taxonomic complex and are taxonomic synonyms. Thus, the following species of bivalve mollusks live in the Black Sea: Crassostrea gigas, Mytillus galloprovincialis and Flexopecten glaber. All of them are characterized by a significant drop in haplotypic diversity and an alien species – the Pacific oyster – also a decrease in nucleotide diversity.

Mitochondrial DNA Barcoding of the Pacific Oyster Crassostrea gigas (Thunberg, 1793) (Mollusca: Bivalvia: Ostreidae), Cultivated in the Black Sea

2018 ◽  
Vol 54 (12) ◽  
pp. 1445-1451
Author(s):  
Yu. V. Slynko ◽  
E. E. Slynko ◽  
A. V. Pirkova ◽  
L. V. Ladygina ◽  
V. I. Ryabushko
Keyword(s):  
Mitochondrial Dna ◽  
Dna Barcoding ◽  
Black Sea ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
The Black Sea ◽  
The Pacific

scholarly journals Adaptive strategy of Rapana venosa (Gastropoda, Muricidae) in the invasive population of the Black Sea

2020 ◽  
Vol 28 (1) ◽  
pp. 48-52
Author(s):  
Е. Е. Slynko ◽  
Y. V. Slynko ◽  
V. I. Rabushko
Keyword(s):  
Genetic Diversity ◽  
Black Sea ◽  
Molecular Genetic ◽  
Coi Gene ◽  
The Black Sea ◽  
The Sea Of Japan ◽  
High Fertility ◽  
Rapana Venosa ◽  
Morphological Studies ◽  
Rapa Whelk

We conducted molecular-genetic and morphological studies on the veined rapa whelk Rapana venosa (Valenciennes, 1846) in the Crimean waters of the Black Sea in order to determine possible reasons of the invasive success of this mollusk. Molecular-genetic tests were performed using COI gene; the surveyed samples reliably identified to R. venosa species. We compared the data on initial (from the Far-Eastern seas) and some invasive populations. In the natural conditions of the Yellow, East China Seas, and the Sea of Japan, the genetic diversity of rapa whelk is high (Hd = 0.933, π = 0.002). In all the invasive populations of rapa whelk (Black Sea, European and North American), an extremely low level of haplotypic and nucleotide diversity was determined (Hd = 0.0, π = 0.0). Despite low values of genetic diversity, the invasive populations of rapa whelk are characterized by ecological success. We noted stable growth of populations, tolerance to diseases and parasites, effective reproduction, high fertility. This contradicts the main provisions of the population genetics theory of formation of edge of range populations, because usually only a small number of specimens of rapa whelk were introduced. The explanations of the unique condition of the invasive populations of rapa whelk, both from an ecological perspective (high resistance to fluctuations of hydrological factors and chemical pollution, absence of enemies, high fertility) and genetic perspective (high selective value of separate haplotypes settled in the new water areas) have not been confirmed. We determined that a very important factor for the naturalization of the rapa whelk at low genetic diversity is the intra-species morpho-ecological divergence. In the Crimean water area of the Black Sea, R. venosa was found to have two morpho-ecological forms associated with the peculiarities of the development of the proportions of the shell. Study of successful invasive species would allow timely and adequate reaction to new cases of introduction.

scholarly journals The first record of rock-boring mollusc Petricola lithophaga (Retzius, 1788) inside the valves of oysters Crassostrea gigas (Thunberg, 1793), cultivated in Crimea (the Donuzlav Bay, the Black Sea)

2021 ◽  
Vol 6 (1) ◽  
pp. 34-40
Author(s):  
M. A. Kovalyova ◽  
O. Yu. Vyalova
Keyword(s):  
Black Sea ◽  
Crassostrea Gigas ◽  
Larval Settlement ◽  
First Record ◽  
The Black Sea ◽  
Bivalve Molluscs ◽  
The Caucasus ◽  
Development Cycle ◽  
The Pacific ◽  
Study Species

The number of mollusc farms off the coast of Crimea and the Caucasus has increased significantly in recent years. The cultivation of the Pacific oyster Crassostrea gigas (Thunberg, 1793) requires monitoring of mollusc health and parasitological control of mariculture farms. The aim of this work was to study species composition of epibionts and endobionts, associated with shells of cultivated oyster C. gigas, as well as to identify species, damaging shells. Commercial oysters with visual shell damage were collected on a mariculture farm in the Donuzlav Bay (Crimea, the Black Sea) and brought to the laboratory alive chilled. As a result of 22 oysters’ examination, 14 macrozoobenthos species and live specimens of rock-boring mollusc Petricola lithophaga (Retzius, 1788) were found. The size of rock-borers varied 9 to 16 mm; their age was about two years. Prolonged presence of P. lithophaga inside oyster valves can cause degradation of shell calcareous layer and even death of the mollusc host; this fact is of great importance for the Black Sea mariculture. Considering P. lithophaga annual development cycle, during the period of mass larval settlement (July to October), it is recommended to inspect the shells of cultivated oysters. Further detailed studies will allow to develop measures for prevention and protection of bivalve molluscs from infestation with P. lithophaga.

Overt and Concealed Genetic Loads Revealed by QTL Mapping of Genotype-dependent Viability in the Pacific Oyster Crassostrea gigas

Genetics ◽  
2021 ◽  
Author(s):  
Xiaoshen Yin ◽  
Dennis Hedgecock
Keyword(s):  
Genetic Diversity ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Genetic Load ◽  
High Density ◽  
High Genetic Diversity ◽  
High Fecundity ◽  
Recessive Mutations ◽  
Genotype Frequencies ◽  
The Pacific

Abstract Understanding the genetic bases of inbreeding depression, heterosis, and genetic load is integral to understanding how genetic diversity is maintained in natural populations. The Pacific oyster Crassostrea gigas, like many long-lived plants, has high fecundity and high early mortality (type-III survivorship), manifesting a large, overt, genetic load; the oyster harbors an even greater concealed genetic load revealed by inbreeding. Here, we map viability QTL (vQTL) in six interrelated F2 oyster families, using high-density linkage maps of single nucleotide polymorphisms generated by genotyping-by-sequencing (GBS) methods. Altogether, we detect 70 vQTL and provisionally infer 89 causal mutations, 11 to 20 per family. Genetic mortality caused by independent (unlinked) vQTL ranges from 94.2% to 97.8% across families, consistent with previous reports. High-density maps provide better resolution of genetic mechanisms, however. Models of one causal mutation present in both identical-by-descent (IBD) homozygotes and heterozygotes fit genotype frequencies at 37 vQTL; consistent with the mutation-selection balance theory of genetic load, 20 are highly deleterious, completely recessive mutations and 17 are less deleterious, partially dominant mutations. Another 22 vQTL require pairs of recessive or partially dominant causal mutations, half showing selection against recessive mutations linked in repulsion, producing pseudo-overdominance. Only eight vQTL appear to support the overdominance theory of genetic load, with deficiencies of both IBD homozygotes, but at least four of these are likely caused by pseudo-overdominance. Evidence for epistasis is absent. A high mutation rate, random genetic drift, and pseudo-overdominance may explain both the oyster’s extremely high genetic diversity and a high genetic load maintained primarily by mutation-selection balance.

Genetic diversity of an avian nasal schistosome causing cercarial dermatitis in the Black Sea-Mediterranean migratory route

2018 ◽  
Vol 117 (12) ◽  
pp. 3821-3833 ◽  
Author(s):  
Keyhan Ashrafi ◽  
Alireza Nouroosta ◽  
Meysam Sharifdini ◽  
Mohammad Reza Mahmoudi ◽  
Behnaz Rahmati ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Black Sea ◽  
The Black Sea ◽  
Cercarial Dermatitis ◽  
Migratory Route
Sign in / Sign up

Export Citation Format

Share Document