SNP (Single Nucleotide Polymorphism) molecular marker related to grass carp body weight character and application thereof

Abstract

The invention belongs to the technical field of aquatic animal molecular markers and aquatic genetic breeding, and particularly discloses an SNP (Single Nucleotide Polymorphism) molecular marker remarkably related to grass carp body weight traits and application thereof. The SNP molecular marker is shown as follows: (1) SLG1123629389 with the polymorphic base being T / C, (2) SLG1127776299 with the polymorphic base being A / G, (3) SLG1127776356 with the polymorphic base being G / A, and (4) SLG1235362696 with the polymorphic base being T / C. The invention also discloses application of the SNP molecular marker, the amplification primer or the kit in breeding grass carp with excellent growth traits. The SNP molecular marker disclosed by the invention can be used for early breeding of grass carp with excellent growth traits, so that the breeding workload is greatly reduced, the breeding time can be remarkably shortened, the breeding process is accelerated, the breeding efficiency is improved, and the breeding cost is reduced; the method has important guiding significance for improving the production performance of the grass carp, reducing the culture cost of the grass carp and increasing the culture income, and is suitable for popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical fields of molecular markers of aquatic animals and aquatic genetic breeding, and specifically relates to SNP molecular markers related to the body weight trait of grass carp and their applications. Background Art

[0002] Grass carp (Ctenopharyngodon idella) is the leading economic fish in freshwater aquaculture in China. The genetic improvement of its growth traits is of great significance for enhancing the efficiency of aquaculture. However, the sexual maturity cycle of grass carp is as long as 4 to 5 years, resulting in an extremely long breeding cycle and low breeding efficiency, which severely restricts the development of the grass carp seed industry. Therefore, there is an urgent need to develop molecular markers related to growth traits for molecular marker-assisted breeding of grass carp, so as to screen out individuals with excellent growth traits and then apply them to the next generation of breeding.

[0003] Molecular markers are genetic markers based on nucleotide sequence variations in the genetic material between individuals, directly reflecting genetic polymorphisms at the DNA level. Among them, single nucleotide polymorphism (SNP), as the third-generation molecular marker, has the largest number and the widest distribution in the genome, so it is widely used in molecular breeding of animals and plants. SNP refers to DNA sequence polymorphisms caused by single nucleotide variations at the genome level, and such variations can be single-base substitutions, insertions or deletions. Molecular marker-assisted breeding is a breeding technique that utilizes the characteristics of these molecular markers being closely linked to genes controlling target traits to select target traits by detecting molecular markers. However, there is currently a lack of molecular markers for molecular marker-assisted breeding of grass carp growth traits, which restricts the improvement of grass carp growth traits. Summary of the Invention

[0004] The purpose of the present invention is to provide SNP molecular markers related to the body weight trait of grass carp and their applications to solve the above problems.

[0005] To achieve the above purpose, the specific technical solutions adopted by the present invention are as follows:

[0006] In the first aspect, the present invention provides SNP molecular markers related to the body weight trait of grass carp, and the SNP molecular markers are one or more of the following 1), 2), 3), and 4):

[0007] 1) Located at position 23629389 on chromosome 11 of grass carp, the polymorphic base is T / C, which is referred to as molecular marker SNP SLG11_23629389 in this article;

[0008] 2) Located at position 27,776,299 on chromosome 11 of grass carp, the polymorphic base is A / G, which is referred to as molecular marker SNP SLG11_27776299 in this article;

[0009] 3) Located at position 27,776,356 on chromosome 11 of grass carp, the polymorphic base is G / A, which is referred to as molecular marker SNP SLG11_27776356 in this article;

[0010] 4) Located at position 35,362,696 on chromosome 12 of grass carp, the polymorphic base is T / C, which is referred to as molecular marker SNP SLG12_35362696 in this article.

[0011] In the second aspect, the present invention provides amplification primers for detecting the SNP molecular markers, including primer pairs capable of detecting one or several of the above four SNP molecular markers 1)-4).

[0012] Preferably, the amplification primers include the following one or more pairs:

[0013] A pair of primer pairs shown in SEQ ID NO:1 and SEQ ID NO:2, capable of amplifying molecular marker SNP SLG11_23629389;

[0014] A pair of primer pairs shown in SEQ ID NO:3 and SEQ ID NO:4, capable of amplifying molecular marker SNP SLG11_27776299;

[0015] A pair of primer pairs shown in SEQ ID NO:5 and SEQ ID NO:6, capable of amplifying molecular marker SNP SLG11_27776356;

[0016] A pair of primer pairs shown in SEQ ID NO:7 and SEQ ID NO:8, capable of amplifying molecular marker SNP SLG12_35362696.

[0017] In the third aspect, the present invention provides a method for breeding grass carp with excellent growth traits, including the following steps:

[0018] Step 1: Extract the fin DNA of the grass carp individuals to be detected;

[0019] Step 2: Using the genomic DNA in Step 1 as a template, perform PCR amplification with the amplification primers;

[0020] Step 3: Perform sequencing analysis on the amplification products obtained in Step 2 to determine the genotypes of the SNP molecular markers of the grass carp individuals to be detected, and determine whether the grass carp has the potential for excellent growth traits through genotype analysis.

[0021] Preferably, in step 3, when performing PCR amplification with a pair of primers shown in SEQ ID NO:1 and ID NO:2, a polymorphic base at position 23629389 on chromosome 11 of grass carp is detected, and grass carp with the genotype CC (the base sequence is as shown in SEQ ID NO:9) has the potential for excellent growth traits.

[0022] Preferably, in step 3, when performing PCR amplification with a pair of primers shown in SEQ ID NO:3 and ID NO:4, a polymorphic base at position 27776299 on chromosome 11 is detected, and grass carp with the genotype AG (the base sequence is as shown in SEQID NO:10) has the potential for excellent growth traits.

[0023] Preferably, in step 3, when performing PCR amplification with a pair of primers shown in SEQ ID NO:5 and ID NO:6, a polymorphic base at position 27776356 on chromosome 11 of grass carp is detected, and grass carp with the genotype GA (the base sequence is as shown in SEQ ID NO:11) has the potential for excellent growth traits.

[0024] Preferably, in step 3, when performing PCR amplification with a pair of primers shown in SEQ ID NO:7 and ID NO:8, a polymorphic base at position 35362696 on chromosome 12 of grass carp is detected, and grass carp with the genotype CC (the base sequence is as shown in SEQ ID NO:12) has the potential for excellent growth traits.

[0025] When the molecular marker is SNP SLG11_23629389, grass carp with the genotype CC has a faster growth rate, while grass carp with the genotypes TC and TT have a slower growth rate; when the molecular marker is SNP SLG11_27776299, grass carp with the genotype AG has better growth traits than grass carp carrying the genotype AA; when the molecular marker is SNP SLG11_27776356, grass carp with the genotype GA has better growth traits than grass carp carrying the genotype GG; when the molecular marker is SNPSLG12_35362696, grass carp with the genotype CC has better growth traits than grass carp with the genotypes TC and TT.

[0026] Fourthly, the present invention provides a kit containing the amplification primers, and the amplification primers include one or more of the following pairs: SEQ ID NO:1-2, SEQ ID NO:3-4, SEQ ID NO:5-6, SEQ ID NO:7-8.

[0027] Fifth aspect, the present invention provides the application of the SNP molecular marker, amplification primer or kit in breeding grass carp with excellent growth traits.

[0028] The present invention has the following beneficial effects:

[0029] (1) Through genome-wide association analysis, the present invention analyzes the gene loci controlling the growth traits of grass carp and screens four candidate SNP loci significantly associated with growth traits (body weight), namely SNP SLG11_23629389, SNP SLG11_27776299, SNP SLG11_27776356 and SNP SLG12_35362696. It is found that in SNP SLG11_23629389, the CC genotype is the preferred genotype; in SNP SLG 11_27776299, the AG genotype is the preferred genotype; in SNP SLG11_27776356, the GA genotype is the preferred genotype; in SNP SLG12_35362696, the CC genotype is the preferred genotype. Individuals carrying the above preferred genotypes have more prominent growth traits. These four SNPs can be used as molecular markers to predict the growth rate of grass carp with high accuracy. The SNP loci of the present invention have application prospects in molecular marker-assisted breeding of grass carp.

[0030] (2) The SNP markers of the present invention can be determined by primers, and have the advantages of simple and fast operation, accurate and reliable results, and low cost.

[0031] (3) The SNP molecular markers of the present invention are not affected by factors such as individual age and gender. The SNP molecular markers can be used for early selection of grass carp with excellent growth traits, greatly reducing the breeding workload, significantly shortening the breeding time, accelerating the breeding process, improving the breeding efficiency, and reducing the breeding cost; it has important guiding significance for improving the production performance of grass carp, reducing the breeding cost of grass carp and increasing the breeding income, and is suitable for popularization and application. Description of the Drawings

[0032] Figure 1 It is the Manhattan plot and QQ plot in the GWAS analysis of the body weight trait of grass carp provided by the embodiment of the present invention, where 1A is the Manhattan plot and 1B is the QQ plot.

[0033] Figure 2 It is the statistical result diagram of the body weight of grass carp carrying different genotypes of SNP SLG11_23629389 in the embodiment of the present invention, where 2A is the screening result of whole-genome high-throughput sequencing and 2B is the verification result of first-generation sequencing.

[0034] Figure 3It is the statistical result graph of the body weights of grass carps carrying different genotypes of SNP SLG11_27776299 in the embodiments of the present invention, where 3A is the screening result of whole-genome high-throughput sequencing, and 3B is the verification result of first-generation sequencing.

[0035] Figure 4 It is the statistical result graph of the body weights of grass carps carrying different genotypes of SNP SLG11_27776356 in the embodiments of the present invention, where 4A is the screening result of whole-genome high-throughput sequencing, and 4B is the verification result of first-generation sequencing.

[0036] Figure 5 It is the statistical result graph of the body weights of grass carps carrying different genotypes of SNP SLG12_35362696 in the embodiments of the present invention, where 5A is the screening result of whole-genome high-throughput sequencing, and 5B is the verification result of first-generation sequencing. Detailed implementation manners

[0037] The present invention focuses on the genetic improvement of the growth traits of grass carps, applies SNP molecular marker information to the molecular marker breeding of grass carp growth traits, screens molecular markers related to grass carp growth traits, which has simple and fast detection operations, accurate and reliable results, and low costs, and is suitable for popularization and use.

[0038] To enable those skilled in the art to better understand the technical solutions of the present invention, the following embodiments are provided for illustration.

[0039] Example 1: Screening of SNP molecular markers related to the body weight trait of grass carp individuals

[0040] 1. Sample collection

[0041] The grass carps used in this study were collected from the Wujiang National Four Major Carp Farms in Jiangsu Province, China. 584 healthy grass carp individuals were selected, the body weight data of each fish was measured and recorded, and the caudal fin tissues of the experimental fish were collected for the extraction of genomic DNA.

[0042] 2. Extraction of genomic DNA

[0043] The magnetic bead method was used for the extraction of sample DNA. The concentration of the DNA sample was detected with a Qubit fluorescence quantifier; the integrity of the DNA sample was detected by 1% agarose gel electrophoresis. The extracted DNA was subjected to high-throughput sequencing.

[0044] 3. SNP quality control and population structure analysis

[0045] The original high-throughput sequencing data was processed using quality control and filtering, and PLINK software was used 49Set thresholds, including missing rate > 0.1, minor allele frequency (MAF) < 0.05, call rate < 0.1, and Hardy-Weinberg equilibrium (HWE) < 1e-6, to remove low-quality SNPs from the original data. Finally, 62,736 high-quality SNP sites were obtained for subsequent analysis.

[0046] Before starting the genome-wide association study, to avoid the influence of population structure, the quality-controlled data was first subjected to principal component analysis (PCA) using the PLINK software, and visualization was performed using the R package ggplot2. The phylogenetic tree was constructed using the raxml-ng software and visualized using the website (https: / / itol.embl.de).

[0047] 4. Genome-wide association study of body weight traits

[0048] The genome-wide association study was conducted using the Tassel software based on the General Linear Model (GLM) method to perform a genome-wide association study on the body weight traits of 584 individuals, while fully considering the population structure and the kinship between individuals. The statistical model is as follows:

[0049] y = Xα + Zβ + e

[0050] In the formula, y represents the phenotypic trait; Xα is the population structure, acting as a fixed effect; Zβ is the marker effect, and e is the residual.

[0051] The Bonferroni correction (Bonferroni 1936) was used to determine the genome-wide significant threshold calculation formula p-value = 0.05 / N, where N represents the total number of markers used for the association analysis. The QQ plot and Manhattan plot were both drawn using the R language CMplot package, and the phenotypic variance explained (PVE) and F-value were calculated using the Tassel software.

[0052] 5. Result analysis

[0053] After quality control and cleaning by PLINK, 62,736 SNP sites of 584 grass carp individuals were obtained for further GWAS analysis. The genome-wide significant SNP marker threshold after Bonferroni correction was set to P = 0.05 / 62736 = 7.97×10 -7 . The GWAS results for the grass carp body weight trait are as Figure 1Shown: A total of 8 SNPs significantly associated with the body weight trait of grass carp were detected on chromosomes 11, 12, 16, and 24 at the genomic level. Among them, 3 were detected on chromosome 11 and 1 on chromosome 12, and the SNPs with the strongest association with the body weight trait of grass carp were SNP SLG11_23629389T>C, SNP SLG11_27776299A>G, SNP SLG11_27776356G>A, and SNP SLG12_35362696T>C (where SNP SLG11_27776299 and SNP SLG11_27776356 were marked as overlapping in Figure 1 due to being too close).

[0054] The statistical results of the body weight data of four SNP loci with different genotypes of 584 grass carp in this example are as shown in Figure 2 Figure A-5A. Specifically, the body weights of individuals with different genotypes of SNP SLG11_23629389T>C are as shown in Figure 2 Figure A. There were significant differences in the average body weights of grass carp with three genotypes at the SNP SLG11_23629389T>C locus. Among them, the average body weight of grass carp carrying the CC genotype (20.8 g) was significantly higher than that of individuals carrying the TC genotype (17.6 g) and the TT genotype (17.3 g) (P<0.05). The body weights of individuals with different genotypes of SNP SLG11_27776299A>G are as shown in Figure 3 Figure A. There were significant differences in the average body weights of grass carp with two genotypes at the SNP SLG11_27776299A>G locus. Among them, the average body weight of grass carp carrying the AG genotype (21.7 g) was significantly higher than that of individuals carrying the AA genotype (17.8 g) (P<0.05). The body weights of individuals with different genotypes of SNP SLG11_27776356G>A are as shown in Figure 4 Figure A. There were significant differences in the average body weights of grass carp with two genotypes at the SNP SLG11_27776356G>A locus. Among them, the average body weight of grass carp carrying the GA genotype (21.7 g) was significantly higher than that of individuals carrying the GG genotype (17.8 g) (P<0.05). The body weights of individuals with different genotypes of SNP SLG12_35362696T>C are as shown in Figure 5 Figure A. There were significant differences in the average body weights of grass carp with three genotypes at the SNP SLG12_35362696T>C locus. Among them, the average body weight of grass carp carrying the CC genotype (33.1 g) was significantly higher than that of individuals carrying the TC genotype (21.8 g) and the TT genotype (18 g); there were also significant differences in the average body weights between individuals carrying the TC genotype and the TT genotype (P<0.05).

[0055] Example 2: Verification of SNP Molecular Markers Related to the Body Weight Trait of Grass Carp Individuals

[0056] For the verification test, different grass carp populations were used. 50 experimental fish were randomly selected, and the body weight trait indexes of each fish were measured and recorded. At the same time, caudal fin samples of each fish were collected and stored for DNA extraction. The specific process of DNA extraction was the same as that in Example 1. Subsequently, using the extracted DNA as a template, PCR amplification was carried out with SEQ ID NO:1 and SEQ ID NO:2 as primers. The amplification system used in the PCR reaction was calculated as 20 μl: 1 μl of 100 ng / μl template DNA, 0.5 μl of 10 pmol / μl forward primer and reverse primer each, 10 μl of Taq Mix, and the balance was double-distilled water.

[0057] The PCR reaction program was as follows: The conditions of the PCR reaction were: pre-denaturation at 94 °C for 5 min; denaturation at 94 °C for 30 s, annealing at 55 °C or 60 °C for 30 s, extension at 72 °C for 30 s, for a total of 30 - 35 cycles; incubation at 72 °C for 7 min. A gene fragment (SEQ ID NO:9) containing SNP SLG11_23629389T>C was obtained. As shown in SEQ ID NO:9, the mutation site was located at the 201st position, and its mutation type was T / C.

[0058] The sequences of the upstream and downstream primer pairs of the SNP SLG11_23629389 were as follows:

[0059] SNP SLG11_23629389-F: 5’-GTAGGAGTGTTGAACTGTCT-3’ (SEQ ID NO:1);

[0060] SNP SLG11_23629389-R: 5’-GCATGTACGCACAATCTT-3’ (SEQ ID NO:2).

[0061] The molecular marker sequence was as shown in SEQ ID NO:9. SNP SLG11_23629389T>C was located at the 201st position of the gene fragment SEQ ID NO:9, and the mutation type was T / C.

[0062] SEQ ID NO:9 (wherein, the double underline indicates the mutation site, and the single underline is the position of the upstream and downstream primers):

[0063]

[0064] The genotypes of each individual were obtained by first-generation sequencing of the PCR amplification products, and the body weight data of individuals with different genotypes were statistically analyzed. Figure 2Figure B shows the results of experimental verification of SNP SLG11_23629389. As Figure 2 shown in Figure B, there are significant differences in body weight among individuals with different genotypes of SNP SLG11_23629389 in grass carp; among them, the body weight of individuals carrying the CC genotype (22.1 g) is higher than that of individuals carrying the genotypes TC (15.6 g) and TT (15.8 g), which is consistent with the results of Example 1 Figure 2 A.

[0065] The verification method for SNP SLG11_27776299A>G is the same as above. The upstream and downstream primers used are:

[0066] SNP SLG11_27776299-F: 5’-ACAGCAACAGAGTCATCAA-3’ (SEQ ID NO: 3);

[0067] SNP SLG11_27776299-R: 5’-AGGATTGACAACGGCATT-3’ (SEQ ID NO: 4).

[0068] The gene fragment containing SNP SLG11_27776299 is shown in SEQ ID NO: 10. The mutation site is located at the 201st position, and its mutation type is A / G.

[0069] SEQ ID NO:10 (wherein, the double underline indicates the mutation site, and the single underline is the position of the upstream and downstream primers):

[0070]

[0071]

[0072] Figure 3 Figure B shows the results of experimental verification of SNP SLG11_27776299. As Figure 3 shown in Figure B, there are significant differences in body weight among individuals with different genotypes of grass carp SNP SLG11_27776299; among them, the body weight of individuals carrying the AG genotype (21.9 g) is higher than that of individuals carrying the AA genotype (17 g), which is consistent with the results of Example 1 Figure 3 A.

[0073] The verification method for SNP SLG11_27776356G>A is the same as above. The upstream and downstream primers used are:

[0074] SNP SLG11_27776356G>A-F: 5’-ATGACTCCTCTGTTGACTG-3’ (SEQ ID NO: 5);

[0075] SNP SLG11_27776356 G>A - R: 5’-AGGATTGACAACGGCATT-3’ (SEQ ID NO: 6).

[0076] Obtain the gene fragment containing SNP SLG11_27776356 as shown in SEQ ID NO: 11. The mutation site is at position 201, and the mutation type is G / A.

[0077] SEQ ID NO:11 (wherein, the double underline indicates the mutation site, and the single underline is the position of the upstream and downstream primers):

[0078]

[0079] Figure 4 B shows the results of experimental verification of SNP SLG11_27776356. From Figure 4 B, it can be seen that there are significant differences in body weight among individuals with different genotypes of grass carp SNP SLG11_27776356; among them, the body weight of individuals carrying the GA genotype (21.9 g) is higher than that of individuals carrying the GG genotype (17 g), which is consistent with the results of Example 1 Figure 4 A.

[0080] The verification method of SNP SLG12_35362696 T>C is the same as above. The upstream and downstream primers used are:

[0081] SNP SLG12_35362696 T>C - F: 5’-GAGCAACTGCCATTGAGA-3’ (SEQ ID NO: 7);

[0082] SNP SLG12_35362696 T>C - R: 5’-TCATAGTGCTGCTTACTCAA-3’ (SEQ ID NO: 8).

[0083] Obtain the gene fragment containing SNP SLG12_35362696 as shown in SEQ ID NO: 12. The mutation site is at position 201, and the mutation type is T / C.

[0084] SEQ ID NO:12 (wherein, the double underline indicates the mutation site, and the single underline is the position of the upstream and downstream primers):

[0085]

[0086] Figure 5 B shows the results of experimental verification of SNP SLG12_35362696. From Figure 5It can be seen from B that there are significant differences in body weight among individuals with different genotypes of grass carp SNPSLG12_35362696; among them, the body weight of individuals carrying the CC genotype (33.1 g) is higher than that of individuals carrying the genotypes TC (21.6 g) and TT (17.5 g), which is consistent with Example 1 Figure 5 A. The results are consistent.

[0087] In summary, the four SNP markers (SNP SLG11_23629389, SNP SLG11_27776299, SNP SLG11_27776356, and SNP SLG12_35362696) screened in the present invention are significantly associated with the growth traits of grass carp, and their genotypes can be determined by a pair of primers respectively, with simple and reliable operation. These four SNP loci have application prospects in molecular marker-assisted breeding and genomic selection breeding of grass carp.

[0088] Although the present invention has been described in detail above with general descriptions and specific embodiments, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. SNP molecular markers related to the body weight trait of grass carp, characterized in that, The SNP molecular markers are one or more of the following 1), 2), 3), and 4): 1) Located at position 23629389 on chromosome 11 of grass carp, the polymorphic base is T / C; 2) Located at position 27776299 on chromosome 11 of grass carp, the polymorphic base is A / G; 3) Located at position 27776356 on chromosome 11 of grass carp, the polymorphic base is G / A; 4) Located at position 35362696 on chromosome 12 of grass carp, the polymorphic base is T / C.

2. Amplification primers for detecting the SNP molecular marker described in claim 1, characterized in that, It includes primer pairs capable of detecting one or several of the four SNP molecular markers.

3. The amplification primer according to claim 2, wherein It includes the following one or more pairs: A pair of primer pairs shown in SEQ ID NO:1 and SEQ ID NO:2, used to detect molecular marker 1); A pair of primer pairs shown in SEQ ID NO:3 and SEQ ID NO:4, used to detect molecular marker 2); A pair of primer pairs shown in SEQ ID NO:5 and SEQ ID NO:6, used to detect molecular marker 3); A pair of primer pairs shown in SEQ ID NO:7 and SEQ ID NO:8, used to detect molecular marker 4).

4. A method for breeding grass carp with excellent growth traits, characterized in that, It includes the following steps: Step 1: Extract the fin DNA of the grass carp individual to be detected; Step 2: Using the genomic DNA in Step 1 as a template, perform PCR amplification with the amplification primers described in Claim 2 or 3; Step 3: Sequence and analyze the amplification product obtained in Step 2 to determine the genotype of the SNP molecular marker of the grass carp individual to be detected, and determine whether the grass carp has the potential for excellent growth traits through genotype analysis.

5. The method for breeding grass carp with excellent growth traits according to claim 4, characterized in that, It includes the following steps: In Step 3, when performing PCR amplification with a pair of primer pairs shown in SEQ ID NO:1 and SEQ ID NO:2, detect the polymorphic base at position 23629389 on chromosome 11 of grass carp. Grass carp with the genotype CC has the potential for excellent growth traits.

6. The method for breeding grass carps with excellent growth traits according to claim 4, characterized in that, It includes the following steps: In Step 3, when performing PCR amplification with a pair of primer pairs shown in SEQ ID NO:3 and SEQ ID NO:4, detect the polymorphic base at position 27776299 on chromosome 11 of grass carp. Grass carp with the genotype AG has the potential for excellent growth traits.

7. The method for breeding grass carp with excellent growth traits according to claim 4, characterized in that, It includes the following steps: In Step 3, when performing PCR amplification with a pair of primer pairs shown in SEQ ID NO:5 and SEQ ID NO:6, detect the polymorphic base at position 27776356 on chromosome 11 of grass carp. Grass carp with the genotype GA has the potential for excellent growth traits.

8. The method for breeding grass carps with excellent growth traits according to claim 4, characterized in that, It includes the following steps: In Step 3, when performing PCR amplification with a pair of primer pairs shown in SEQ ID NO:7 and SEQ ID NO:8, detect the polymorphic base at position 35362696 on chromosome 12 of grass carp. Grass carp with the genotype CC has the potential for excellent growth traits.

9. A kit containing the amplification primers described in Claim 2 or 3.

10. Use of the SNP molecular marker according to claim 1, the amplification primer according to claim 2 or 3, or the kit according to claim 9 in breeding grass carp with excellent growth traits.

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