Exploring the Genetic Diversity and Population Structure of Daphnia cucullata Sars, 1862 in Boreal Lakes (Latvian Lakeland) Based on Microsatellites
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article presents interesting data on intra- and inter-population variability of Daphnia cucullata – species that are very common in Europe, however, it is often omitted in genetic analyses (contrary to other Daphnia species). The characteristics of the 9 microsatellites locus and primers for the Daphnia genus are interesting.
The aim of the study should be improved - determining the genetic structure of Daphnia cucullata native population it's not very revealing. The authors previously mentioned that microsatellite loci are frequently used in studies of the genetic structure of the Daphnia genus (with lack of D. cucullata). Maybe the authors could consider phylogenetic analyses of the genus Daphnia? Another issue that should be developed based on the data obtained is: intra-population vs. inter-population variability
The abstract and its language should be improved. Furthermore, the whole manuscript needs professional native-speaker correction (sentence structures, numerous errors, etc.)
Please check carefully the References.
More comments and a few minor corrections are in the pdf file.
Comments for author File: 
Comments.pdf
The English language needs extensive editing by a professional native speaker before publication.
Author Response
Dear Reviewer!
We thank for interest in our work and for helpful comments that will greatly improve the manuscript. We have checked all the general and specific comments and have made necessary changes accordingly to indications and have tried to do our best to respond to the points raised.
Answers to reviewer questions.
“Maybe the authors could consider phylogenetic analyzes of the genus Daphnia? Another issue that should be developed based on the data obtained is: intra-population vs. inter-population variability”
Thank you for the idea. Maybe in our next study, we could consider phylogenetic analyzes of the genus Daphnia in Baltic and other countries, but at this moment the idea of our study is to research markers for the population genetic study of D.cucullata and to study the genetic structure of D.cucullata populations from some Latvian lakes as part of the Boreal zone.
“The abstract and its language should be improved. Furthermore, the whole manuscript needs professional native-speaker correction (sentence structures, numerous errors, etc.)”
Thank you, we understand this, and our manuscript will be sent to the editorial office of the journal, where we were kindly offered to make English corrections
“Please check carefully the References”
Thank you, we checked the References in our manuscript and made the necessary corrections.
Reviewer 2 Report
Comments and Suggestions for AuthorsThis is potentially good MS, and I can recommend to publish it, but after a major revision. My comments are mainly represented in the text, even I was trying to edit some sentences. FIRST OF ALL, the MS MUST be shown to a native speaker, as English is not so good. I am not native speaker, but I see many very clumsy sentences. Moreover, many separate sentences and the text in general must be strongly shorten. The Introduction is in general OK, but the Discussion must be strongly re-worked.
The main problem that the authors try to discuss some questions concerning the population structure of Daphnia cucullata based on four localities only. But such conclusions could not be accurately checked statistically. May be I am wrong, but does really PCA necessary for four localities only? The authirs said nothing about normal distribution of values. Are the clusters in the PCA axes really significant? If we will put 20 more populations to the same dataset, are You sure that the clusters will be separate? They can join together easily.
As I can understand, the author speculations on some fine differences between lakes are very premature. In my understanding, such discussion is fully speculative: we any case will find some differences. I strongly recommend to the authors to cut TWO TIMES their discussion section, and each time think about a sampling gap, local factors, etc.
Also the authors try to discuss some fine differences between populations of Daphnia cucullata from different regions, what shortened their aims and significance of their results. Again, fine differences between regions could be discussed based on better material, i.e. number of sampled lakes and geographic range.
In contrast, I think that the authors could strongly shift their discussion to another direction. They need to speak (1) about all Daphnia, (2) about advantages of microsatellites as compared to data on mitochondrial phylogeography of different taxa (D. galeata, curvirostris, magna).
Such approach is more beneficial for the authors themselves.
I believe that several days will be OK to do this.
I wish the authors a great success!!!!
Comments for author File: Comments.pdf
The manuscript must be definitively edited by a native speaker! Many sentences are too clumsy. The MS must be shortened.
Author Response
Dear Reviewer!
We thank for interest in our work and for helpful comments that will greatly improve the manuscript. We have checked all the general and specific comments and have made necessary changes accordingly to indications and have tried to do our best to respond to the points raised.
Answers to reviewer questions.
“This is potentially good MS, and I can recommend to publish it, but after a major revision. My comments are mainly represented in the text, even I was trying to edit some sentences. FIRST OF ALL, the MS MUST be shown to a native speaker, as English is not so good. I am not native speaker, but I see many very clumsy sentences”.
Thank you, we understand this, and our manuscript will be sent to the editorial office of the journal, where we were kindly offered to make English corrections
“Moreover, many separate sentences and the text in general must be strongly shorten”.
Thank you, We have shortened or divided many sentences and significantly shortened and re-worked the discussion.
“The main problem that the authors try to discuss some questions concerning the population structure of Daphnia cucullata based on four localities only. But such conclusions could not be accurately checked statistically. May be I am wrong, but does really PCA necessary for four localities only? The authirs said nothing about normal distribution of values. Are the clusters in the PCA axes really significant? If we will put 20 more populations to the same dataset, are You sure that the clusters will be separate? They can join together easily”.
Thank you, You're right. But one of the aims of our investigation for the first time, was to test microsatellite markers for studying the genetic structure of D.cucullata populations in native water bodies in Latvian Lakeland as part of the Boreal region for the next study. We were interested in the genetic structure of D.cucullata populations in hydrologically similar water bodies, such as deep lakes, which have similar environmental conditions. There are few such lakes. in Latvian Lakeland
“As I can understand, the author speculations on some fine differences between lakes are very premature. In my understanding, such discussion is fully speculative: we any case will find some differences. I strongly recommend to the authors to cut TWO TIMES their discussion section, and each time think about a sampling gap, local factors, etc”.
In accordance with your recommendations, we have significantly shortened the discussion by removing or combining many arguments.
“Also the authors try to discuss some fine differences between populations of Daphnia cucullata from different regions, what shortened their aims and significance of their results. Again, fine differences between regions could be discussed based on better material, i.e. number of sampled lakes and geographic range. In contrast, I think that the authors could strongly shift their discussion to another direction. They need to speak (1) about all Daphnia, (2) about advantages of microsatellites as compared to data on mitochondrial phylogeography of different taxa (D. galeata, curvirostris, magna). Such approach is more beneficial for the authors themselves”.
We have added a few sentences about that, we used these microsatellite markers for the analysis of natural populations of D.cucullata in Latvian Lakeland for the first time and our use of markers turned out to be very successful because we were able to detect subtle differences between populations that exist in hydrologically similar conditions in natural lakes and therefore this microsatellites can be useful for larger-scale studies on geographic ranges of D.cucullata in Boreal region.
A very important point that you emphasized about the absence of Boreal and Continental biogeographical regions!!!
Writing our manuscript, we were relies on the distribution of biogeographical regions in Europe what available in Biogeographical regions in Europe — European Environment Agency (europa.eu). This map reflects the status of the Biogeographical Regions in Europe from 2016 onwards.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript has been revised and looks better. The authors answered my questions and doubts satisfactorily.
PS. Please remove the large paragraph from the abstract. Maybe change the title to:
Exploring the genetic diversity and population structure of Daphnia cucullata Sars, 1862 in Boreal lakes
Or
Native populations of Daphnia cucullata Sars, 1862 in Boreal lakes: genetic structure
Comments on the Quality of English LanguageThe language has been improved, but still requires moderate editing before publication.
Author Response
Dear Reviewer!
We thank for interest in our work and for helpful comments that will greatly improve the manuscript. We have checked all the general and specific comments and have made necessary changes accordingly to indications and have tried to do our best to respond to the points raised.
Answers to reviewer questions.
- Please remove the large paragraph from the abstract
Based on your suggestions we remove the large paragraph from the abstract.
- Maybe change the title to:
Exploring the genetic diversity and population structure of Daphnia cucullata Sars, 1862 in Boreal lakes
Or
Native populations of Daphnia cucullata Sars, 1862 in Boreal lakes: genetic structure
We change the title to:
Exploring the genetic diversity and population structure of Daphnia cucullata Sars, 1862 in Boreal lakes (Latvian Lakeland) based on microsattelites.
3. We checked again English.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors did not follow my recommendations, but it is their right, of course. But still the Discussion sections is too speculative. It is very large, although, in my understanding, the authors could discuss only few topics except of their four lakes. Differences from different "regions" (Baltic "region" is represented by four lakes!) are not statistically significant and could be quite random. Still my recommendation is to reduce the Discussion section (two times!) having many items out of author's scope.
Also, again, English could be checked – see incomplete sentence in the Abstract.
Comments for author File: Comments.pdf
Author Response
Dear Reviewer!
We thank for interest in our work and for helpful comments that will greatly improve the manuscript. We have checked all the general and specific comments and have made necessary changes accordingly to indications and have tried to do our best to respond to the points raised.
Answers to reviewer questions.
- Still my recommendation is to reduce the Discussion section (two times!) having many items out of author’s scope.
In accordance with your recommendations, we have significantly reduced the Discussion section again. For example, about metapopulation, about parthenogenetic process, and others.
- Differences from different "regions" (Baltic "region" is represented by four lakes!) are not statistically significant and could be quite random.
Thank you, You're right, but, in each case, when we speaking about lakes from Boreal region, we emphasized that we are talking specifically of Latvian Lakeland. For example, Boreal region (Latvian Lakeland).
- We added in Discussion section a small part about genetic markers in coding with the aim of our study.
- We checked again English.
