Genetic diversity of zebra mussel (Dreissena polymorpha (Pallas, 1771)) as a reflection of successful invasion into the water bodies in Baltic Sea region

Dreissena polymorpha, the zebra mussel, is one of the most widespread and ecologically disruptive invasive species in European freshwater systems. Despite its long presence in Latvia, genetic information on local populations has been lacking. This study provides the first comprehensive assessment of genetic diversity and population structure of D. polymorpha across seven Latvian waterbodies, representing lakes, a reservoir, and a river system. Individuals were genotyped using five polymorphic microsatellite loci. Genetic variation was analysed through the standard genetic parameters, namely, number of alleles and frequency, heterozygosity estimates and genetic differentiation was estimated using F_ST statistics, Bayesian clustering, PCA, and Nei’s genetic distance. All loci were polymorphic, and no evidence of null alleles or recent bottlenecks was detected. Populations exhibited high genetic diversity. Significant heterozygote deficits were found in most populations. Genetic differentiation among populations was moderate overall, though three geographically proximate lakes showed minimal differentiation. Bayesian clustering and PCA identified four distinct genetic groups, indicating that hydrological isolation and limited dispersal contribute to population structuring. These findings demonstrate that Latvian D. polymorpha populations maintain substantial genetic diversity and exhibit clear spatial genetic structuring. This genetic information provides an essential foundation for monitoring invasion dynamics and informing management strategies aimed at limiting further spread and ecological impact.

Astanei I, Gosling E, Wilson J, Powell E, 2005. Genetic variability and phylogeography of the invasive zebra mussel, Dreissena polymorpha (Pallas). Mol Ecol 14:1655-1666. DOI: https://doi.org/10.1111/j.1365-294X.2005.02530.x

Birnbaum C, 2011. NOBANIS – Invasive Alien Species Fact Sheet – Dreissena polymorpha. Online Database of the European Network on Invasive Alien Species. Accessed: 25 October 2025. Available from: https://www.nonnativespecies.org/assets/Invasive_Alien_Species_Fact_Sheet_-_Dreissena_polymorpha_-_NOBANIS_-_downloaded_from_website_March_2014.pdf

Brown JE, Stepien CA, 2009. Invasion genetics of the Eurasian round goby in North America: tracing sources and spread patterns. Mol Ecol 18:64-79. DOI: https://doi.org/10.1111/j.1365-294X.2008.04014.x

Chapuis MP, Estoup A, 2007. Microsatellite null alleles and estimation of population differentiation. Mol Bio. Evol 24:621-631. DOI: https://doi.org/10.1093/molbev/msl191

Chen Y, Zhao L, Teng H, Shi C, Liu Q, Zhang J, Zhang Y, 2021. Population genomics reveal rapid genetic differentiation in a recently invasive population of Rattus norvegicus. Front Zool 18:6. DOI: https://doi.org/10.1186/s12983-021-00387-z

Cornuet JM, Luikart G, 1996. Description and power analysis of two tests for detecting recent population bottlenecks from allele frequency data. Genetics 144:2001-2014. DOI: https://doi.org/10.1093/genetics/144.4.2001

Doorenweerd C, San Jose M, Barr N, Leblanc L, Rubinoff D, 2020. Highly variable COI haplotype diversity between three species of invasive pest fruit fly reflects remarkably incongruent demographic histories. Sci Rep 10:6887. DOI: https://doi.org/10.1038/s41598-020-63973-x

Estoup A, Ravigné V, Hufbauer R, Vitalis R, Gautier M, Facon B, 2016. Is there a genetic paradox of biological invasion? Annu Rev Ecol Evol Syst 47:51-72. DOI: https://doi.org/10.1146/annurev-ecolsys-121415-032116

Evanno G, Regnaut S, Goudet J, 2005. Detecting the number of clusters of individuals using the software STRUCTURE: A simulation study. Mol Ecol 14:2611-2620. DOI: https://doi.org/10.1111/j.1365-294X.2005.02553.x

Feldheim KA, Brown JE, Murphy DJ, Stepien CA, 2011. Microsatellite loci for dreissenid mussels (Mollusca: Bivalvia: Dreissenidae) and relatives: markers for assessing exotic and native populations. Mo. Ecol Resour 11:725-732. DOI: https://doi.org/10.1111/j.1755-0998.2011.03012.x

Francis RM, 2017. Pophelper: an R package and web app to analyse and visualize population structure. Mol Ecol Resour 17:27-32. DOI: https://doi.org/10.1111/1755-0998.12509

Gelembiuk GW, May GE, Lee CE, 2006. Phylogeography and systematics of zebra mussels and related species. Mol Ecol 15:1033-1050. DOI: https://doi.org/10.1111/j.1365-294X.2006.02816.x

Gosling E, Astanei I, Was A, 2008. Genetic variability in Irish populations of the invasive zebra mussel, Dreissena polymorpha: Discordant estimates of population differentiation from allozymes and microsatellites. Freshwater Biol 53:1303-1315. DOI: https://doi.org/10.1111/j.1365-2427.2008.01965.x

Hartl DL, Clark AG, 1997. Principles of population genetics. Sinauer Associates, Sunderland.

HELCOM, 2020. Abundance and distribution of the Zebra mussel (Dreissena polymorpha). Baltic Sea Environment Fact Sheet. Accessed: 25 October 2025. Available from: https://helcom.fi/wp-content/uploads/2020/06/BSEFS-Abundance-and-distribution-of-the-Zebra-mussel.pdf

Hubisz MJ, Falush D, Stephens M, Pritchard AJ, 2009. Inferring weak population structure with the assistance of sample group information. Mol Ecol Resour 9:1322-1332. DOI: https://doi.org/10.1111/j.1755-0998.2009.02591.x

Johnson LE, Carlton JT, 1996. Biological invasions and cryptogenic species. Ecology 77:1653-1655. DOI: https://doi.org/10.2307/2265767

Langella O, 2007. Populations 1.2.30: Population genetic software (individuals or populations distances, phylogenetic trees). Accessed: 25 October 2025. Available from: http://bioinformatics.org/~tryphon/populations/

Lowe S, Browne M, Boudjelas S, De Poorter M, 2000. 100 of the World’s Worst Invasive Alien Species: A selection from the Global Invasive Species Database. IUCN/ISSG. Accessed: 25 October 2025. Available from: https://www.iucngisd.org/gisd/100_worst.php

Mallez S, McCartney M, 2018. Dispersal mechanisms for zebra mussels: Population genetics supports clustered invasions over spread from hub lakes in Minnesota. Biol Invasions 20:2461-2484. DOI: https://doi.org/10.1007/s10530-018-1714-3

Marescaux J, von Oheimb KCM, Etoundi E, von Oheimb PV, Albrecht C, Wilke T, Van Doninck K, 2016. Unravelling the invasion pathways of the quagga mussel (Dreissena rostriformis) into western Europe. Biol Invasions 18:245-264. DOI: https://doi.org/10.1007/s10530-015-1005-1

Marshall NT, Stepien CA, 2021. Genetic trajectories of zebra and quagga mussel invasions across three decades: Lake Erie versus Hudson River populations. Aquat Invasions 16:147-166. DOI: https://doi.org/10.3391/ai.2021.16.1.10

Morozova A, Shkute N, 2023. Genetic characteristics of the Dreissena polymorpha population in Latvia (Lake Rāzna) as part of the European population. Arch Biol Sci 75:133-139. DOI: https://doi.org/10.2298/ABS230202011M

Müller JC, Hidde D, Seitz A, 2002. Canal construction destroys the barrier between major European invasion lineages of the zebra mussel. Proc Biol Sci 269:1139-1142. DOI: https://doi.org/10.1098/rspb.2002.1994

Naish KA, Boulding EG, 2001. Trinucleotide microsatellite loci for the zebra mussel Dreissena polymorpha, an invasive species in Europe and North America. Mol Ecol Notes 1:286-298. DOI: https://doi.org/10.1046/j.1471-8278.2001.00111.x

Nei M, Tajima F, Tateno Y, 1983. Accuracy of estimated phylogenetic trees from molecular data. II. Gene frequency data. J Mol Evol 19:153-170. DOI: https://doi.org/10.1007/BF02300753

Olson JR, McCartney MA, Witt JDS, 2018. Dispersal potential of zebra mussel larvae in flowing water. Aquat. Invasions 13:311-322.

Orlova MI, Panov VE, 200). Establishment of the zebra mussel, Dreissena polymorpha (Pallas), in the Neva Estuary (Gulf of Finland, Baltic Sea): distribution, population structure and possible impact on local unionid bivalves. Hydrobiologia 514:207-217. DOI: https://doi.org/10.1007/978-94-017-0920-0_19

Page RD, 1996. TreeView: An application to display phylogenetic trees on personal computers. Bioinformatics 12:357-358. DOI: https://doi.org/10.1093/bioinformatics/12.4.357

Peakall R, Smouse PE, 2006. GENALEX 6: Genetic analysis in Excel. Population genetic software for teaching and research. Mol Ecol Notes 6:228-295. DOI: https://doi.org/10.1111/j.1471-8286.2005.01155.x

Peñarrubia L, Vidal O, Viñas J, Pla C, Sanz N, 2016. Genetic characterization of the invasive zebra mussel (Dreissena polymorpha) in the Iberian Peninsula. Hydrobiologia 779:227-242. DOI: https://doi.org/10.1007/s10750-016-2819-2

Ricciardi A, Hill JM, 202). Passive transport of a zebra mussel attached to a freshwater fish: A novel Dreissena dispersal mechanism? Biol Invasions 25:2057-2060. DOI: https://doi.org/10.1007/s10530-023-03036-0

Rice WR, 1989. Analyzing tables of statistical tests. Evolution 43:223-225. DOI: https://doi.org/10.1111/j.1558-5646.1989.tb04220.x

Selkoe KA, Toonen RJ, 2006. Microsatellites for ecologists: A practical guide to using and evaluating microsatellite markers. Ecol Lett 9:615-629. DOI: https://doi.org/10.1111/j.1461-0248.2006.00889.x

Stepien CA, Taylor CD, Dabrowska KA, 2002. Genetic variability and phylogeographical patterns of a nonindigenous species invasion: A comparison of exotic vs. native zebra and quagga mussel populations. J Evol Biol 15:314-328. DOI: https://doi.org/10.1046/j.1420-9101.2002.00385.x

Therriault T, Orlova M, Docker M, MacIsaac HJ, Heath DD, 2005. Invasion genetics of a freshwater mussel (Dreissena rostriformis bugensis) in eastern Europe: high gene flow and multiple introductions. Heredity 9516-23. DOI: https://doi.org/10.1038/sj.hdy.6800691

Travina OV, Bespalaya YV, Kondakov AV, Vikhrev IV, Aksenova OV, Aksenov AS, et al. 2025. Genetic diversity and expansion routes of the invasive zebra mussel Dreissena polymorpha in Eastern Europe. Hydrobiologia 852:1743-1758. DOI: https://doi.org/10.1007/s10750-024-05772-3

Van Oosterhout C, Hutchinson WF, Wills DPM, Shipley P, 2004. MICRO-CHECKER: software for identifying and correcting genotyping errors in microsatellite data. Mol Ecol Notes 4:535-538. DOI: https://doi.org/10.1111/j.1471-8286.2004.00684.x

Weir BS, Cockerham CC, 1984. Estimating F-statistics for the analysis of population structure. Evolution 38:1358-1370. DOI: https://doi.org/10.1111/j.1558-5646.1984.tb05657.x

Wright S, 1978. Evolution and the genetics of population. Variability within and among natural populations. University of Chicago Press, Chicago.

Zając K, Bonk M, 2019. New records of the invasive bivalve Dreissena polymorpha (Pallas, 1771) (Bivalvia: Dreissenidae) in the Carpathian Mountains. Folia Malacol 27:231-234. DOI: https://doi.org/10.12657/folmal.027.023