Spatiotemporal genetic structure in theDaphnia pulexcomplex from Sierra Nevada lakes (Spain): reproductive mode and first record of North AmericanD.cf.pulexin European alpine lakes

Abstract

Daphnia is a good model organism for studying factors affecting dispersal and patterns of genetic diversity. Within this genus, the Daphnia pulex species complex includes lineages from North America and Europe, with some considered invaders in various continents, although their colonization history is poorly known. We used mitochondrial DNA and microsatellite markers to identify the D. pulex complex lineages in Sierra Nevada, determine their reproductive mode and reconstruct their genetic history (over the past ~25 to 65 years). We present the first recording of North American (NA) D. cf. pulex in a European high-mountain lake, showing its arrival ~65 years ago in lake Borreguil without temporal changes in its genetic structure. European (Eu) D. cf. pulicaria is the only lineage present in other Sierra Nevada lakes and also showed no genetic change over time. The results for both species are congruent with obligate parthenogenetic reproduction mode. Moreover, water mineralization may influence the clonal distribution of the D. pulex complex in Sierra Nevada, without ruling out dispersal limitation and/or founder effects. Although NA D. cf. pulex had not spread to other Sierra Nevada lakes, it could threaten Eu D. cf. pulicaria in Sierra Nevada and other European alpine lakes.

Population genetic dynamics during colonisation and establishment of an obligate parthenogenetic Daphnia pulex population in a small lake of a continental archipelago

“…However, Dane et al (2020) noted that the limitations of their study were in the small sample sizes (tens of diapausing eggs analysed in each research site) and limited resolution of the genetic markers used (eight microsatellite loci), which might have caused a failure to detect minor genotypes coexisting with the major one. This is also the case for Conde‐Porcuna et al (2021).…”

“…We can extract DNA from these preserved diapausing eggs, and thereby reconstruct population genetic dynamics (Burge et al, 2018; Orsini et al, 2016). Although previous studies have revealed the evolutionary processes of Daphnia using diapausing eggs (e.g., Decaestecker et al, 2007; Hairston et al, 1999; Stoks et al, 2016), only three prior studies have observed long‐term genetic dynamics of Daphnia species including the early stage of colonisation (Conde‐Porcuna et al, 2021; Dane et al, 2020; Möst et al, 2015). Möst et al (2015) analysed 40 years of long‐term genetic dynamics of colonisation and establishment by Daphnia pulicaria that consisted of cyclic parthenogenetic lineages and possibly a few obligate parthenogenetic lineages.…”

“…Möst et al (2015) analysed 40 years of long‐term genetic dynamics of colonisation and establishment by Daphnia pulicaria that consisted of cyclic parthenogenetic lineages and possibly a few obligate parthenogenetic lineages. Dane et al (2020) and Conde‐Porcuna et al (2021) analysed long‐term genetic dynamics of an obligate parthenogenetic Daphnia pulex species complex. Dane et al (2020) observed the population genetic dynamics of obligate parthenogenetic D. pulicaria for three centuries including colonisation of three lakes in Greenland.…”

“…Dane et al (2020) observed the population genetic dynamics of obligate parthenogenetic D. pulicaria for three centuries including colonisation of three lakes in Greenland. Conde‐Porcuna et al (2021) observed the population genetic dynamics of obligate parthenogenetic D. pulex , which belonged to the North American lineage, for 65 years in a Spanish high‐mountain lake. These three previous studies showed that limited haplotypes succeeded in colonisation, whereas population genetic dynamics after colonisation differed between the three cases.…”

“…These three previous studies showed that limited haplotypes succeeded in colonisation, whereas population genetic dynamics after colonisation differed between the three cases. Although D. pulicaria populations with cyclic parthenogenetic lineages showed a rapid increase in genetic diversity after colonisation (Möst et al, 2015), obligate parthenogenetic populations were dominated by a single or a few genotypes without increasing genetic diversity over time (Conde‐Porcuna et al, 2021; Dane et al, 2020). Dane et al (2020) showed the dominance of a single genotype that had persisted for 250–300 years in two lakes despite substantial environmental changes during the period.…”