TY - CHAP

T1 - MYTILUS EDULIS AND M.TROSSULUS IDENTIFICATION USING CONCHOLOGICAL CHARACTERS IN OCEANIC AND ESTUARINE HABITATS, THE KOLA PENINSULA (WHITE AND BARENTS SEAS)

AU - Marchenko, Ju.T.

AU - Khaitov , V.M.

AU - Katolikova , M.V.

AU - Strelkov , P.P.

PY - 2019/9/8

Y1 - 2019/9/8

N2 - Mussels Mytilus edulis (МЕ) and M. trossulus (МТ) are species that demandidentification using multilocus genotypes. ME and MT co-occur and hybridize along the coasts ofKola Peninsula. Previous studies have revealed morphological differences between these speciesin the White Sea: the majority of MT bear an uninterrupted dark strip of the prismatic layer underthe ligament on the inner side of the shell (Т-morphotype) while the majority of ME lack thischaracter (E-morphotype). Hybrids are not numerous (about 18% frequency of occurrence in amixed sample), and morphologically are similar to that parent species, whose genes dominate intheir genotypes. This morphological character was first introduced for the purpose ofdiscrimination between MT and M. galloprovincialis in the Russian Pacific Ocean coast.However, discriminative power of the character has been poorly tested in other geographicalregions. The goal of our study was to find out whether morphological differences between MEand MT persist in populations along the Barents Sea coast.ME and MT were sampled in the White Sea (Kandalaksha Bay, 24 samples fromestuarine habitats, salinity up to 25 ppt) and the Barents Sea (Murman coast, 12 samplesfrom estuarine habitats, salinity as in the Whites Sea; 14 samples from oceanic habitats,salinity from 25 to 35 ppt). Mussels were genotyped by four allozyme loci. Contributionof MT and ME genes into individual genotypes was estimated in terms of individualscores obtained by means of a model-based Bayesian clustering method implemented inthe program Structure 2.3.4. To assess associations among the genetic (Structure scores),morphological (T, E-morphotypes) and ecological (oceanic vs. estuarine habitats)variables we used a generalized linear mixed-effect models (GLMMs). Samples wereconsidered as random factors in the analyses. The R programming language with lme4-package was used. We found out that, in the low salinity habitats (White Sea andestuarine Barents Sea samples) differences in morphotype frequencies between МЕ andМТ were 67% and 63%, respectively. In oceanic habitats, differences were much lower:21%, on the average, due to the increased frequency of Т-morphotypes among ME. Wehypothesize that recorded morphological differences between ME from estuarine andoceanic habitats could be due to the ability of a species to adjust the strength of the shellby active production of the nacreous layer under conditions of high acidity in estuaries.Unlike ME, MT does not show such plastic responses. Reliability of ME and MTidentification using specified conchological character is satisfactory high in the estuarine,and low in oceanic habitats across the Kola Peninsula. The probability of correctidentification (when it is conceivable that a mussel with T-morphotype is MT, and amussel with E-morphotype is ME) depends on the taxonomic structure of a sample. E.g.,in pure population of ME, rare mussels with T-morphotypes will be 100% ME. For theconvenience of mussel researches we present the “T-calculator”: statistical functionsrelating the frequency of T-morphotype in population to frequency of MT genes and theaccuracy of ME and MT identification using conchological character. The calculator hasbeen developed for populations from places with salinity below 25 ppt.The research was conducted in a frame of governmental project АААА-А19-119011690138-0 by MES of Russia andproject 19-74-20024 by RSF.

AB - Mussels Mytilus edulis (МЕ) and M. trossulus (МТ) are species that demandidentification using multilocus genotypes. ME and MT co-occur and hybridize along the coasts ofKola Peninsula. Previous studies have revealed morphological differences between these speciesin the White Sea: the majority of MT bear an uninterrupted dark strip of the prismatic layer underthe ligament on the inner side of the shell (Т-morphotype) while the majority of ME lack thischaracter (E-morphotype). Hybrids are not numerous (about 18% frequency of occurrence in amixed sample), and morphologically are similar to that parent species, whose genes dominate intheir genotypes. This morphological character was first introduced for the purpose ofdiscrimination between MT and M. galloprovincialis in the Russian Pacific Ocean coast.However, discriminative power of the character has been poorly tested in other geographicalregions. The goal of our study was to find out whether morphological differences between MEand MT persist in populations along the Barents Sea coast.ME and MT were sampled in the White Sea (Kandalaksha Bay, 24 samples fromestuarine habitats, salinity up to 25 ppt) and the Barents Sea (Murman coast, 12 samplesfrom estuarine habitats, salinity as in the Whites Sea; 14 samples from oceanic habitats,salinity from 25 to 35 ppt). Mussels were genotyped by four allozyme loci. Contributionof MT and ME genes into individual genotypes was estimated in terms of individualscores obtained by means of a model-based Bayesian clustering method implemented inthe program Structure 2.3.4. To assess associations among the genetic (Structure scores),morphological (T, E-morphotypes) and ecological (oceanic vs. estuarine habitats)variables we used a generalized linear mixed-effect models (GLMMs). Samples wereconsidered as random factors in the analyses. The R programming language with lme4-package was used. We found out that, in the low salinity habitats (White Sea andestuarine Barents Sea samples) differences in morphotype frequencies between МЕ andМТ were 67% and 63%, respectively. In oceanic habitats, differences were much lower:21%, on the average, due to the increased frequency of Т-morphotypes among ME. Wehypothesize that recorded morphological differences between ME from estuarine andoceanic habitats could be due to the ability of a species to adjust the strength of the shellby active production of the nacreous layer under conditions of high acidity in estuaries.Unlike ME, MT does not show such plastic responses. Reliability of ME and MTidentification using specified conchological character is satisfactory high in the estuarine,and low in oceanic habitats across the Kola Peninsula. The probability of correctidentification (when it is conceivable that a mussel with T-morphotype is MT, and amussel with E-morphotype is ME) depends on the taxonomic structure of a sample. E.g.,in pure population of ME, rare mussels with T-morphotypes will be 100% ME. For theconvenience of mussel researches we present the “T-calculator”: statistical functionsrelating the frequency of T-morphotype in population to frequency of MT genes and theaccuracy of ME and MT identification using conchological character. The calculator hasbeen developed for populations from places with salinity below 25 ppt.The research was conducted in a frame of governmental project АААА-А19-119011690138-0 by MES of Russia andproject 19-74-20024 by RSF.

M3 - Other chapter contribution

SN - 9785744446079

SP - 39

BT - Modern Achievements in Population, Evolutionary, and Ecological Genetics: International Symposium

A2 - Kartavtsev, Yuri Ph.

A2 - Katugin, Oleg N.

PB - СКБ САМИ ДВО РАН

CY - Vladivostok

T2 - Modern Achievements in Population, Evolutionary, and Ecological Genetics

Y2 - 8 September 2019 through 13 September 2019

ER -