SNP (Single Nucleotide Polymorphism) molecular marker related to backfat thickness character of 100 kg living body of pig and application of SNP molecular marker

Abstract

The invention discloses an SNP molecular marker related to the backfat thickness character of a pig living body with the weight of 100 kg and application of the SNP molecular marker. SNP typing data is obtained by integrating re-sequencing data of the pig and comparing the re-sequencing data of the pig to a pig reference genome Sscrofa11.1, whole genome analysis is conducted through a mixed linear model, 5053 SNP sites related to the backfat thickness of the pig living body with the weight of 100 kg are screened out, and the SNP molecular marker related to the backfat thickness character of the pig living body with the weight of 100 kg is obtained. The correlation between the SNP sites and the backfat thickness character of the pig living body with the weight of 100 kg reaches a remarkable level, a new molecular marker is provided for auxiliary selection and improvement of the backfat thickness character of the pig living body with the weight of 100 kg, and the molecular marker has important significance for auxiliary breeding of pigs.

Description

Technical Field

[0001] The present invention relates to the fields of molecular biotechnology and molecular marker technology, and specifically to SNP molecular markers related to the trait of live backfat thickness at 100 kg body weight of pigs and their applications. Background Art

[0002] Pigs are important economic animals in livestock production. For ten thousand years, pigs and humans have had a close and complex relationship. Wild boars appeared in Southeast Asia and then spread to Eurasia. Domestic pigs originated from the domestication of Eurasian wild boars. From domestication to modern breeding practices, humans have shaped the genome of domestic pigs (Groenen, M. A., A. L. Archibald, H. Uenishi, C. K. Tuggle, Y. Takeuchi, M. F. Rothschild, C. Rogel-Gaillard, et al. Analyses of Pig Genomes Provide Insight into Porcine Demography and Evolution. Nature 491, no. 7424 (Nov 15 2012): 393 - 8.). After thousands of years of natural and artificial selection, there are significant genetic differences between European and Asian pig breeds. For example, European pig breeds have a higher lean meat percentage and faster growth rate, while Asian pig breeds have a higher fat content and the advantages of high litter size and early maturity (Rubin, C. J., H. J. Megens, A. Martinez Barrio, K. Maqbool, S. Sayyab, D. Schwochow, C. Wang, et al. Strong Signatures of Selection in the Domestic Pig Genome. Proc Natl Acad Sci U S A 109, no. 48 (Nov 27 2012): 19529 - 36.). The live backfat thickness at 100 kg body weight is a key predictive indicator for evaluating the lean meat percentage of pigs because there is a strong negative genetic correlation between backfat thickness and lean meat percentage (Zhou P, Yin C, Wang Y, Yin Z, Liu Y. Genomic Association Analysis of Growth and Backfat Traits in Large White Pigs. Genes (Basel). 2023 Jun 13;14(6):1258.). Therefore, exploring and discovering molecular markers related to the genetic mechanism of the live backfat thickness trait at 100 kg body weight helps to better carry out pig breeding research.

[0003] Genome-wide association study (GWAS) was first proposed by Risch in 1996. It is a comprehensive method to explore genetic variations throughout the genome, especially single nucleotide polymorphisms (SNPs). As an association analysis method, GWAS has the advantages of better effect and higher statistical power than linkage analysis in the related research of complex traits. GWAS is a powerful tool for detecting the association between genotyped (or imputed) common single nucleotide polymorphism markers and unknown causal variations through linkage disequilibrium (LD). Genome-wide association analysis has been widely applied in various studies, including various complex human diseases and important economic traits of livestock, etc. (Visscher P M, Brown M A, McCarthy M I, et al. Five years of GWAS discovery[J]. The American Journal of Human Genetics, 2012, 90(1): 7-24.).

[0004] Therefore, exploring SNP molecular markers related to the live backfat thickness trait at 100 kg body weight in pigs is of great significance for the research on the live backfat thickness trait at 100 kg body weight in pigs and pig breeding. Summary of the Invention

[0005] The object of the present invention is to explore new SNP molecular markers related to the live backfat thickness trait at 100 kg body weight in pigs, and provide valuable references for the research on the live backfat thickness trait at 100 kg body weight in pigs and pig breeding.

[0006] In view of this, the solution of the present invention is as follows:

[0007] In one aspect of the present invention, SNP molecular markers related to the live backfat thickness trait at 100 kg body weight in pigs are proposed. The SNP sites of the SNP molecular markers include SNP0001 to SNP5053, and the corresponding positions and mutations on the pig reference genome version Sscrofa11.1 are shown in Table 1.

[0008] The second aspect of the present invention lies in. The application of the SNP molecular markers described in the first aspect in the research on the live backfat thickness trait at 100 kg body weight in pigs and pig breeding.

[0009] Furthermore, the research on the live backfat thickness trait at 100 kg body weight in pigs is to identify the live backfat thickness trait at 100 kg body weight in pigs by using the pig SNP molecular markers described in the first aspect.

[0010] Furthermore, the pig breeding is molecular marker-assisted breeding of pigs.

[0011] Furthermore, the SNP molecular markers are at least one of SNP0332, SNP0335, SNP0338, SNP0339, SNP0342, SNP0345, SNP0348, SNP0350, SNP2890, and SNP2898.

[0012] The third object of the present invention is to provide a method for detecting the live backfat thickness trait of pigs at 100 kg body weight. The steps include detecting the nucleotide mutation types of the pig SNP molecular markers described in the first aspect on the pig chromosome. Specifically, according to the SNP locus-dependent primer design software, primers for amplifying and detecting wild-type or mutant types are obtained, and genotype detection is achieved through PCR amplification, thereby determining the live backfat thickness trait of pigs at 100 kg body weight.

[0013] The fourth object of the present invention is to provide a genetic improvement method for pigs, which determines the SNP molecular markers described in the first aspect of the breeding pigs in the core breeding population of breeding pigs, and makes corresponding selections according to one of the SNP molecular markers: selecting the genotype with low live backfat thickness at 100 kg body weight on chromosome 1 of the reference genome Sscrofa11.1 version of the breeding pigs in the subsequent generations, and eliminating the genotype with high live backfat thickness at 100 kg body weight.

[0014] Furthermore, the SNP molecular markers are SNP0332, SNP0335, SNP0338, SNP0339, SNP0342, SNP0345, SNP0348, SNP0350, SNP2890, and SNP2898.

[0015] Furthermore, the breeding process is as follows:

[0016] For the molecular marker SNP0332, select individuals with TA or AA types at 160174493 bp on chromosome 1, and eliminate individuals with TT type at this point;

[0017] For the molecular marker SNP0335, select individuals with AC or CC types at 160443684 bp on chromosome 1, and eliminate individuals with AA type at this point;

[0018] For the molecular marker SNP0338, select individuals with GA or AA types at 160773437 bp on chromosome 1, and eliminate individuals with GG type at this point;

[0019] For the molecular marker SNP0339, select individuals with GA or AA types at 161037225 bp on chromosome 1, and eliminate individuals with GG type at this point;

[0020] For the molecular marker SNP0342, select individuals with the AG or AA genotype at position 161478793 bp on chromosome 1, and eliminate individuals with the GG genotype at this point;

[0021] For the molecular marker SNP0345, select individuals with the AG or AA genotype at position 161773773 bp on chromosome 1, and eliminate individuals with the GG genotype at this point;

[0022] For the molecular marker SNP0348, select individuals with the CA or CC genotype at position 162028076 bp on chromosome 1, and eliminate individuals with the AA genotype at this point;

[0023] For the molecular marker SNP0350, select the AT or AA genotype at position 162286808 bp on chromosome 1, and eliminate individuals with the TT genotype at this point;

[0024] For the molecular marker SNP2890, select individuals with the TA or AA genotype at position 97617926 bp on chromosome 7, and eliminate individuals with the TT genotype at this point;

[0025] For the molecular marker SNP2898, select individuals with the CT or CC genotype at position 97872646 bp on chromosome 7, and eliminate individuals with the TT genotype at this point.

[0026] Furthermore, the sub - generation selection is carried out generation by generation to gradually increase the frequency of the dominant allele genotypes at the SNP loci, thereby improving and enhancing the growth traits of the offspring pigs.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The SNP loci screened by the present invention have reached a significant level of correlation with the live backfat thickness trait of pigs at 100 kg body weight, providing new molecular markers for the assisted selection and improvement of the live backfat thickness trait of pigs at 100 kg body weight, which is of great significance for the assisted breeding of pigs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic flow chart of the screening process of the SNP loci related to the live backfat thickness trait of pigs at 100 kg body weight according to the present invention.

[0030] Figure 2 It is a Manhattan plot of the results significantly related to the live backfat thickness trait at 100 kg body weight at the whole - genome level in Example 1.

[0031] Figure 3-12These correspond to the difference results of the association analysis of the backfat thickness trait of pigs weighing 100 kg in vivo with different genotypes at the SNP0332, SNP0335, SNP0338, SNP0339, SNP0342, SNP0345, SNP0348, SNP0350, SNP2890, and SNP2898 loci in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the preferred embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] BL-HiChIP (in situ bridge-linked Hi-C followed by chromatin immunoprecipitation) is a method for analyzing chromatin conformation by using the principle of in situ Hi-C and a transposase-mediated library construction. BL-HiChIP crosslinks in the cell nucleus before cell lysis, thus reducing false positives and maximizing the capture efficiency of DNA contacts (Mumbach, M.R., A.J. Rubin, R.A. Flynn, C. Dai, P.A. Khavari, W.J. Greenleaf, and H.Y. Chang. BL-HiChIP: Efficient and Sensitive Analysis of Protein-Directed Genome Architecture. Nat Methods 13, no. 11 (Nov 2016): 919-22.). BL-HiChIP identifies enhancer interactions, and enhancer interactions can link disease variants to target genes. Therefore, we combined the results of GWAS and BL-HiChIP and used BL-HiChIP to determine the potential gene targets of intergenic SNPs, which can further screen candidate genes (Mumbach, M.R., A.T. Satpathy, E.A. Boyle, C. Dai, B.G. Gowen, S.W. Cho, M.L. Nguyen, et al. Enhancer Connectome in Primary Human Cells Identifies Target Genes of Disease-Associated DNA Elements. Nat Genet 49, no. 11 (Nov 2017): 1602-12.).

[0034] In one embodiment, by integrating the resequencing data of 65,623 pigs and using the MVP software with a mixed linear model (Zhang Z, Ersoz E, Lai C Q, et al. Mixed linear model approach adapted for genome-wide association studies[J]. Nature genetics, 2010, 42(4): 355.), SNP molecular markers related to the live backfat thickness trait of pigs at 100 kg body weight were screened out, providing new molecular markers for the assisted selection and improvement of the live backfat thickness trait of pigs at 100 kg body weight, which is of great significance for the assisted screening of pigs.

[0035] In one embodiment, a method for screening SNP molecular markers related to pig growth traits is provided. The method includes the following steps:

[0036] 1) Integrate the resequencing data of 469 pigs of 58 breeds publicly available in the NCBI database (SRA, http: / / www.ncbi.nlm.nih.gov / sra / ) and the European Bioinformatics Institute (EMBL-EBI, https: / / www.ebi.ac.uk / ), and align the pig resequencing data to the pig reference genome (genome version 11.1, Sscrofa11.1) to obtain SNP genotyping data;

[0037] 2) According to the GWAS study in the literature (Horodyska, J., R.M. Hamill, P.F. Varley, H. Reyer, and K. Wimmers. Genome-Wide Association Analysis and Functional Annotation of Positional Candidate Genes for Feed Conversion Efficiency and Growth Rate in Pigs. PLoS One 12, no. 6 (2017): e0173482.), obtain the 5 most significantly-signaled SNPs located on pig chromosome 10, and extract all 17,262 SNP loci located within the same TAD as these 5 SNPs for subsequent epigenetics screening.

[0038] 3) Construct a three-dimensional enhancer-promoter interaction network of the whole pig genome through H3K27ac BL-HiChIP to screen the above SNP loci, and only retain the SNPs that meet all of the following conditions simultaneously: ① located within the loop anchor of BL-HiChIP; ② located within cis-regulatory elements (enhancer or promoter); ③ located within chromatin open regions or transcription factor footprints; ④ the allele frequency difference between 4 commercial lean pig breeds (Large White, Landrace, Duroc, and Pietrain) and 6 Chinese indigenous pig breeds (Meishan, Bamei, Jinhua, Tongcheng, Rongchang, and Erhualian pigs) is greater than 0.5; ⑤ the SNP is predicted by the motifbreakR software to have a strong effect on transcription factor binding. The loci obtained after the above screening are applicable to the breeding of lean pig breeds.

[0039] 4) According to the genotype and phenotypic value of the population, verify the effect of the above-filtered SNP loci on growth rate, and detect whether there are differences in growth rate among pig populations with different alleles.

[0040] It is understandable that taking the allele frequencies of multiple pig breeds greater than 0.5 as the screening condition is to ensure that the population used has sufficient gene pool richness, and the SNP loci screened are meaningful and applicable to all breeds of pigs in the population used. In the above embodiments, the provided molecular markers can be applied to genotype analysis of genes related to pig growth rate or association analysis related to pig growth traits, providing new molecular marker resources for molecular marker-assisted selection of pig growth rate traits.

[0041] Example 1: Screening of SNP molecular markers related to the live backfat thickness trait at 100 kg body weight in pigs

[0042] (1) Genotype detection: Low-depth sequencing data of 65,623 pigs; (2) Data processing: Use Trimmomatic (V0.36) software to perform preliminary quality control on the fastq files. After this step, use the Burrows-Wheeler Aligner 0.7.17 (BWA) software to align the remaining high-quality reads with the pig reference genome (version 11.1), and select the uniquely aligned sequences for genotyping. In order to obtain high-quality variant data, use the GATK (V4.0.3.0) software to perform quality control through the command 'QUAL<30.0||QD<2.0||FS>60.0||MQ<40.0||SOR>4.0||ReadPosRankSum<-8.0' to obtain genotype data available for GWAS analysis.

[0043] (3) Association analysis: Use the BOLT-LMM model in the MVP package under R language to perform genome-wide association analysis, taking PC1-PC5, enterprise, and birth date as fixed effects, and use the Cmp1ot package in R language to draw the Manhattan plot ( Figure 2 ), and the Manhattan plot shows the combination of SNP loci significantly related to the live backfat thickness trait at 100 kg body weight at the genome-wide level. The red dotted line represents the significance threshold, and the SNPs on the dotted line represent SNP loci with strong associations. Evaluate the association between genotype and phenotype through GWAS association analysis, and finally obtain the results in Table 1. There are 5,053 SNP loci strongly associated with the live backfat thickness trait at 100 kg body weight.

[0044] Table 1: Correlation between SNP loci of molecular markers and the live backfat thickness trait at 100 kg body weight

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[0116] Example 2 Application of SNP Molecular Marker Typing in Detection of Porcine Growth Traits and Breeding

[0117] As Figure 3-12 shown, the box plots of genotypes and phenotypes corresponding to the 10 SNP loci with the smallest P values in the order of chromosome positions are SNP0332, SNP0335, SNP0338, SNP0339, SNP0342, SNP0345, SNP0348, SNP0350, SNP2890, and SNP2898. The figure legends are explained as follows: 0 represents wild-type homozygosity. 1 represents heterozygosity. 2 represents mutant homozygosity. The asterisk represents the significance level between the two genotypes. As Figure 3 shown: The difference in FCR between 0 and 1 is extremely significant (p < 0.001), the difference in FCR between 1 and 2 is extremely significant (p < 0.001), and the difference in FCR between 0 and 2 is extremely significant (p < 0.001).Figures 3 to 12 The SNP locus is a site mutation that has been verified to have a significant difference in the live backfat thickness at 100 kg body weight.

[0118] Specifically, the locus numbered SNP0332 is located at the 160,174,493rd base on chromosome 1, and it is an allelic gene mutation of T-A. Figure 3 It shows that for individuals with the genotype TA or AA, their live backfat thickness at 100 kg body weight is significantly lower than that of TT-type individuals. The SNP0332 marker reaches the genome-wide significant level, indicating that this marker is not only significantly correlated with the live backfat thickness trait of pigs at 100 kg body weight, but also when this marker mutates to A, it is beneficial for pigs to have a lower live backfat thickness at 100 kg body weight. In pig breeding, individuals with the genotype TA or AA at the 160,174,493rd base on chromosome 1 can be retained, and TT-type individuals can be eliminated, thereby reducing the live backfat thickness at 100 kg body weight and increasing the lean meat rate.

[0119] The locus numbered SNP0335 is located at the 160,443,684th base on chromosome 1, and it is an allelic gene mutation of A-C. Figure 4 It shows that for individuals with the genotype AC or CC, their live backfat thickness at 100 kg body weight is significantly lower than that of AA-type individuals. Under the Mann-Whitney-U one-tailed test, the SNP0335 marker reaches the genome-wide significant level (P<0.05), indicating that this marker is not only significantly correlated with the live backfat thickness trait of pigs at 100 kg body weight, but also when this marker mutates to C, it is beneficial for pigs to have a lower live backfat thickness at 100 kg body weight.

[0120] The locus numbered SNP0338 is located at the 160,773,437th base on chromosome 1, and it is an allelic gene mutation of G-A. Figure 5 It shows that for individuals with the genotype GA or AA, their live backfat thickness at 100 kg body weight is significantly lower than that of GG-type individuals. And when this marker mutates to A, it is beneficial for pigs to have a lower live backfat thickness at 100 kg body weight. In pig breeding, GA-type or AA-type individuals at 160,773,437 bp on chromosome 1 are selected and retained, and GG-type individuals at this point are eliminated, thereby reducing the live backfat thickness of pigs at 100 kg body weight and increasing the lean meat rate.

[0121] The locus numbered SNP0339 is located at the 161,037,225th base on chromosome 1, and it is an allelic gene mutation of G-A. Figure 6It shows that for GA or AA individuals, the live backfat thickness at 100 kg body weight is significantly lower than that of GG individuals. And when this marker mutates to A, it is beneficial for pigs to have a lower live backfat thickness at 100 kg body weight. By selecting GA or AA individuals at 161037225 bp on chromosome 1 and eliminating GG individuals at this point, the live backfat thickness of pigs at 100 kg body weight can be reduced, and the lean meat rate can be increased.

[0122] The locus of SNP0342 is located at the 161478793rd base of chromosome 1, and it is an A-G allelic gene mutation. Figure 7 It shows that for AG or AA genotype individuals, their feed-to-meat ratio is significantly higher than that of GG individuals, that is, the live backfat thickness of wild-type and heterozygous mutant types at 100 kg body weight is significantly lower than that of homozygous mutant GG individuals. By selecting AG or AA individuals at 161478793 bp on chromosome 1 and eliminating GG individuals at this point, the live backfat thickness of pigs at 100 kg body weight can be reduced, and the lean meat rate can be increased.

[0123] The locus of SNP0345 is located at the 161773773rd base of chromosome 1, and it is an A-G allelic gene mutation. Figure 8 It shows that for AG or AA genotype individuals, their live backfat thickness at 100 kg body weight is significantly lower than that of GG individuals, and when this marker mutates to G, it is not beneficial for pigs to have a lower live backfat thickness at 100 kg body weight. By selecting AG or AA individuals at 161773773 bp on chromosome 1 and eliminating GG individuals at this point, the live backfat thickness of pigs at 100 kg body weight can be reduced, and the lean meat rate can be increased.

[0124] The locus of SNP0348 is located at the 162028076th base of chromosome 1, and it is a C-A allelic gene mutation. Figure 9 It shows that for CA or CC individuals, their live backfat thickness at 100 kg body weight is significantly lower than that of AA individuals, and when this marker mutates to A, it is not beneficial for pigs to have a lower live backfat thickness at 100 kg body weight. By selecting CA or CC individuals at 162028076 bp on chromosome 1 and eliminating AA individuals at this point, the live backfat thickness of pigs at 100 kg body weight can be reduced, and the lean meat rate can be increased.

[0125] The locus of SNP0350 is located at the 162286808th base of chromosome 1, and it is an A-T allelic gene mutation. Figure 10It shows that for individuals with the genotype AT or AA, their live backfat thickness at 100 kg body weight is significantly lower than that of TT individuals, and when the marker is A, it is beneficial for pigs to have a lower live backfat thickness at 100 kg body weight. By selecting AT or AA genotypes at the 162286808 bp position on chromosome 1 and eliminating TT individuals at this point, the live backfat thickness of pigs at 100 kg body weight can be reduced, and the lean meat percentage can be increased.

[0126] The locus of SNP2890 is located at the 97617926th base on chromosome 7 and is an allelic gene mutation of T - A. Figure 11 It shows that for individuals with the genotype TA or AA, their live backfat thickness at 100 kg body weight is significantly lower than that of TT individuals, that is, the live backfat thickness of homozygous mutant and heterozygous mutant individuals at 100 kg body weight is significantly lower than that of wild - type TT individuals. By selecting TA or AA individuals at the 97617926 bp position on chromosome 7 and eliminating TT individuals at this point, the live backfat thickness of pigs at 100 kg body weight can be reduced, and the lean meat percentage can be increased.

[0127] The locus of SNP2898 is located at the 97872646th base on chromosome 7 and is an allelic gene mutation of C - T. Figure 12 It shows that for individuals with the genotype CT or CC, their live backfat thickness at 100 kg body weight is significantly lower than that of TT individuals, that is, when the marker is C, it is beneficial for pigs to have a lower live backfat thickness at 100 kg body weight. By selecting CC or CT individuals at the 97872646 bp position on chromosome 7 and eliminating TT individuals at this point, the live backfat thickness of pigs at 100 kg body weight can be reduced, and the lean meat percentage can be increased.

[0128] By preferentially selecting the advantageous genotypes described at the above SNP loci, the live backfat thickness of pigs at 100 kg body weight can be significantly reduced, and the lean meat percentage can be increased, and ultimately the purpose of improving the economic benefits of commercial pigs can be achieved.

[0129] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A SNP molecular marker associated with the backfat thickness trait of a pig weighing 100 kg in vivo, characterized in that: The SNP sites of the SNP molecular markers include SNP0001 to SNP5053, which correspond to the following positions and mutations on the pig reference genome version Sscrofa11.1:

2. Application of the SNP molecular marker according to claim 1 in the study of the backfat thickness trait of a pig weighing 100 kg in vivo and in pig breeding.

3. The use according to claim 2, characterized in that: The study on the backfat thickness trait of a pig weighing 100 kg in living body is to identify the backfat thickness trait of a pig weighing 100 kg in living body by using the pig SNP molecular marker described in claim 1.

4. The use according to claim 2, characterized in that: The pig breeding is molecular marker assisted breeding of pigs.

5. The use according to claim 2, characterized in that: The SNP molecular marker is at least one of SNP0332, SNP0335, SNP0338, SNP0339, SNP0342, SNP0345, SNP0348, SNP0350, SNP2890, and SNP2898.

6. A method for detecting the backfat thickness of a live pig weighing 100 kg, characterized in that: The steps include detecting the nucleotide mutation type of the pig SNP molecular marker as claimed in claim 1 on the pig chromosome.

7. A method for genetic improvement of pigs, characterized in that: Determine the SNP molecular markers described in claim 1 of the breeding pigs in the breeding pig core group, and make corresponding selections based on one of the SNP molecular markers: the genotype with low back fat thickness at 100 kg body weight on the chromosome of the reference genome Sscrofa11.1 version of the breeding pigs, and eliminate the genotype with high back fat thickness at 100 kg body weight.

8. The use according to claim 7, characterized in that: The SNP molecular markers are SNP0332, SNP0335, SNP0338, SNP0339, SNP0342, SNP0345, SNP0348, SNP0350, SNP2890, and SNP2898.

9. The use according to claim 8, characterized in that: The breeding process is as follows: For the molecular marker SNP0332, TA-type or AA-type individuals at 160174493bp on chromosome 1 were selected, and TT-type individuals at this point were eliminated; For molecular marker SNP0335, select AC or CC individuals at 160443684bp on chromosome 1 and eliminate AA individuals at this point; For molecular marker SNP0338, GA or AA individuals at 160773437bp on chromosome 1 were selected, and GG individuals at this point were eliminated; For molecular marker SNP0339, GA or AA individuals at 161037225bp on chromosome 1 were selected, and GG individuals at this point were eliminated; For molecular marker SNP0342, select AG or AA individuals at bp 161478793 of chromosome 1 and eliminate GG individuals at this point; For molecular marker SNP0345, select AG or AA individuals at bp 161773773 of chromosome 1 and eliminate GG individuals at this point; For molecular marker SNP0348, select CA or CC individuals at 162028076bp of chromosome 1 and eliminate AA individuals at this point; For the molecular marker SNP0350, select the AT or AA type at 162286808bp of chromosome 1 and eliminate the TT type individuals at this point; For the molecular marker SNP2890, select TA or AA individuals at 97617926bp of chromosome 7 and eliminate TT individuals at this point; For the molecular marker SNP2898, CT or CC type individuals at 97872646bp of chromosome 7 were selected, and TT type individuals at this point were eliminated.

10. The use according to claim 7, characterized in that: The successive breeding is carried out generation by generation to gradually increase the frequency of the dominant allele type of the SNP locus, thereby improving and enhancing the growth traits of the offspring pigs.

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