Comparative Analysis of the Polymorphism of the Casein Genes in Camels Bred in Kazakhstan

Round 1

Reviewer 1 Report

Dear authors,

I write you in regards to manuscript # Comparative analysis of the polymorphism of the casein genes in camels bred in Kazakhstan [1632534] Journal: Diversity

 

The authors present an interesting analysis of genetic polymorphisms of casein genes (CSN1S1, CSN2, CSN3) in Camelus dromedarius and Camelus bactrianus with the aim to establish selection programs aimed to improve the camel's milk production and quality. Furthermore, the authors used the obtained data of genetic characterisation in order to describe the genetic diversity and the phylogenetic relationship among the analysed herds. However, I think this manuscript needs considerable revisions.

Also, editing for the English language is required throughout the manuscript in order to make the results and concepts presented clearly understandable.

 

In the following, I will list the points of the manuscript that need improvement.

• The introduction must be revised and improved to give a clear background of the topic in object. In particular, it would include an appropriate description of polymorphisms studied in the article and their effects or associations on milk production traits to follow the description of the results better. 

Delete irrelevant information out of the context of the scope of this paper, for example, the paragraph from line 63 to line 72. 

Revise the discordant information reported in the text, for example, clarify the number of variants identified in αs1-CN.

• Include more details in material and methods. Description of the PCR-RFLP analysis must be improved. If the authors performed for the first time the method, please describe it, in particular how the primer design was performed. Otherwise, include the references for each PCR-RFLP method.
• Include more details in the statistical methodology. Please describe the used Nei’s genetic distances equation including reference, and which algorithm has been used for the Phylogenetic tree construction.
• The discussion section must be implemented. Please extend the text of this section discussing the obtained results of population genetics compared with the literature.

 

Minor comments:

• Lines 62-63 The authors report the following sentence: “Some studies are looking into the genetic factors that influence milk yield increase”.

Please clarify if the above sentence refers to studies focused on Camels; therefore, consider adding references.

• Lines 77-79 Remove the following sentence: “The study of genetic polymorphisms in casein proteins is important because of its impact on the quantitative and technological properties of milk”. It is repeated in lines 100-101.
• Lines 105-106 Delete or rephrase the sentence. It appears out of context.
• Lines 117-120 “Blood samples were collected in the Ile district of the Almaty region of Kazakhstan in October Camel breeding has been a traditional branch of productive livestock breeding in this region for centuries; as a result, there are a large number of camel breeding farms.”

This sentence appears to contain two fused sentences. Consider adding punctuation and splitting the sentence. Describe which kind of vacutainer tubes have been used for the blood collection.

• Table 1 column “Fragment length” replace b.p. with bp
• Table 1 column “Primers” Remove spaces from the sequences of the primers 
• Table 1 Add a column by reporting the PCR RFLP pattern per locus.
• Line 136: delete or move reference 34 from this specific sentence because I don’t understand how it is relevant to visualise PCR products. 
• Table 2- Table 3 Please standardise and uniform the decimal values. 
• Table 2-Table 3 Are the χ2 values referred to the overall sample? Consider resetting the table because it is hard to understand which population χ2 values refer to.
• Lines 162-163 If χ2 refers to the overall sample, please check these values. Furthermore, please consider reporting the HW p-value.
• Line 168 “desired allele” - Why C allele and A allele of the CSN3 and CSN2 gene, respectively, are defined as "desired allele"? I suppose these genetic variants are considered desirable because contribute to affect milk quality traits. Still, the introduction's missing information about these genetic polymorphisms makes it unclear and complex to follow this section of results.
• Lines 182-188 Move this descriptive section in the discussion 
• Line 204 Remove “milk productivity” 
• Lines 212-218 Move this descriptive section in the discussion
• Line 224 Delete “For example”
• Lines 251- 252 The frequency value of the allele G seems to be missing
• Lines 280-286 The authors refer to the so-called “core” population, but it is unclear what the authors mean by core population. Is it related to the so-called desirable genotype? Again, the lack of information in the introduction section regarding the effects of genetic variants makes it difficult to follow this section.

 

The topic of this manuscript is interesting in relation to the valorisation of camel milk quality. However, some critical points need to be improved, mainly because some missing information makes the work confusing and incomplete. Therefore the findings are publishable after the suggested improvements.

Author Response

Dear Reviewer,
Thank you for your review of our paper!
Please see the attachment to find the responses to your comments.

Author Response File: Author Response.pdf

Reviewer 2 Report

Abstract. Line 11 to 16 must be rewritten. Authors use half of the abstract to report introductory information which does not specifically say anything about what was done in this paper. I understand a sentence can be use to introduce but not half the abstract.

Missed numerical results.

The abstract should be a mini version of the paper and should engage the readers into reading the paper. In this case, it is rather the topic used than the manner in which it is presented.

Keywords. Wrong choice of keywords. Search engines already look for words used in the paper. Hence, if you repeat them, you miss an opportunity to be found and thus cited.

Introduction.

Try to avoid lesser than four-line paragraphs.

English needs to be revised.

The aims of this paper must be clearly stated. As it read now, this study seems a rather descriptive one, and I feel more was made here.

M&M

Lines 115 and 166. There is a specific section in MDPI papers for this to be included at the end of the paper.

Sample must be better described. Ages, sexes. What was the inclusion criteria for these camels? Did you choose animals not to belong to the same family or were they relatives? Georeferencing the area where samples were taken. Adding a map could be an option.

Sampling procedures must be precisely described.

Nei’s genetic distance trees must be better disentangled. Which are the factors that make such branches to emerge from parental nodes. What are the particularities of each population? What re the factors involved in these separating?

Discussion was my favourite part of the paper and I do believe there is not much information (contrasted and to be referenced) out there. Authors did a great job with this section. Maybe the start was too sharp, but as the state of the art had been described earlier in the body text, it may not be bad. I would personally conduct the readers thought he accomplishment of the objectives of the paper in the discussion. Please think of it. Conduct the readers in the way that you want your paper to be read.

Conclusions

This section is not well written. It rather addresses future directions. What’s the take home message for readers from this paper?

Author Response

Dear Reviewer,
Thank you for your review of our paper!
Please see the attachment to find the responses to your comments.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

No further comment