Application of the product of detecting SNP molecular marker related to litter weight traits of large white pig

Abstract

The application relates to a product of a SNP molecular marker related to the litter weight trait of Large White pigs, wherein the SNP molecular marker is an A>G base mutation at a nucleic acid site of 116767089 of chromosome 2 in the international pig genome Sscrofa 11.1 version, and the nucleotide sequence is shown as SEQ ID No. 1; the product at least comprises an upstream primer and a downstream primer, the nucleotide sequence of the upstream primer is shown as SEQ ID No. 2, and the nucleotide sequence of the downstream primer is shown as SEQ ID No. 3. The SNP molecular marker can be used for breeding, cultivation and evaluation of multi-species high-reproduction-performance sows.

Description

Technical Field

[0001] This invention relates to a SNP molecular marker technology, specifically to the application of products for detecting SNP molecular markers related to the litter weight trait in Large White pigs. Background Technology

[0002] The reproductive performance of sows is a core factor affecting the economic benefits of pig production, and is directly related to the competitiveness and sustainable development capabilities of breeding enterprises.

[0003] Reproductive traits in pigs encompass multiple indicators, including age at first farrowing, gestation period, number of litters per year, number of teats, total number of piglets born, number of live piglets born, individual birth weight, litter birth weight, number of weaned piglets, and litter weaning weight. Among these, litter birth weight, as the total weight of piglets in a litter at birth, is a crucial trait that comprehensively reflects the sow's reproductive potential, fetal development, and the level of nutritional management during gestation. This trait not only reflects information on both litter size and individual birth weight but also indirectly reveals the coordination of various physiological processes such as uterine capacity, embryo survival rate, placental function, and maternal health.

[0004] In actual production, low litter weight often means that some piglets are born with small birth weights, poor vitality, and weak disease resistance, making them prone to early death or culling during the suckling stage, thus reducing weaning survival rate and increasing breeding costs and risks. In contrast, sows with higher litter weights usually provide more healthy, uniformly weighted piglets, which is beneficial for improving weaning litter weight and subsequent growth performance. Studies have shown a significant positive correlation between litter weight and economic traits such as weaning litter weight, growth rate, and survival rate. Therefore, this trait has been widely regarded as one of the key indicators for evaluating and selecting high-fertility sows. By incorporating litter weight into breeding objectives, not only can the overall reproductive efficiency of the sow population be improved, but it also helps to identify superior boar or sow pedigrees and accelerate the genetic progress of the core breeding herd.

[0005] However, most reproductive traits are of low heritability and are greatly influenced by the environment. Traditional breeding methods are slow, time-consuming, and costly, making it difficult to meet the needs of modern, efficient breeding. With the development of molecular biology techniques, marker-assisted selection (MAS) has provided a new technical approach for pig breeding. This method detects genetic markers associated with target traits, enabling early selection of individual genotypes, thereby shortening generation intervals and improving the accuracy and efficiency of breeding.

[0006] Among various molecular markers, single nucleotide polymorphisms (SNPs) have become the mainstream in genetic marker development and application due to their wide distribution, high stability, ease of standardized detection, and high-throughput analysis. Compared with polymorphic markers such as SSRs and ISSRs, SNPs have higher genetic stability and reproducibility, and can be rapidly and massively screened using various technology platforms such as TaqMan probe assays, mass spectrometry, gene chips, and high-throughput sequencing. As sequencing costs continue to decrease, a large number of SNP markers from multiple species have been discovered and applied to the genetic improvement of important economic traits.

[0007] Despite this, reports of key SNP markers associated with litter weight at birth in pigs remain relatively limited. The literature "Genome-wide Association Analysis of Genetic Diversity and Reproductive Traits in Zaozhuang Black-Capped Pigs," Zhang Ran, dissertation at Shandong Agricultural University, page 31, August 31, 2022, reports that SNPs associated with litter weight at birth are located on chromosomes 6 and 10, while SNPs associated with individual birth weight are located on chromosomes 1 and 2. Among these, the DCP2 gene is associated with individual birth weight shape. Studies have shown that DCP2 is an mRNA uncapping enzyme that degrades maternal transcripts in oocytes, promoting oocyte maturation and embryonic development. CN119842914A reports a C>T mutation at position 105043272 on chromosome 14 of the International Swine Genome Reference Sequence 11.1, affecting reproductive traits in pigs (litter weight, number of healthy piglets, and total litter weight). CN114250305B reports an SNP marker in the GLRX3 gene, located at nucleotide 151219997 on chromosome 14 of the International Swine Genome Reference Sequence 10.2, exhibiting T / C polymorphism, used to assess the number of live piglets and litter weight. However, a marker system suitable for efficient, large-scale molecular breeding practices has not yet been established.

[0008] Therefore, developing SNP markers that are significantly associated with litter weight and suitable for high-throughput genotyping technology is of great practical significance for achieving early selection of sow reproductive traits, improving breeding efficiency, reducing production costs, and promoting genetic progress in the pig industry. Summary of the Invention

[0009] The first technical problem to be solved by this invention is to provide a product for detecting SNP molecular markers related to the birth litter weight trait in Large White pigs, and its application in the breeding of sows for the birth litter weight trait.

[0010] The second technical problem to be solved by the present invention is to provide a product for detecting SNP molecular markers related to the litter weight trait of Large White pigs and its application in breeding high-yielding litter weight sow breeds.

[0011] The third technical problem to be solved by the present invention is to provide a product for detecting SNP molecular markers related to the birth litter weight trait in Large White pigs and its application in improving the birth litter weight trait in sow populations.

[0012] The fourth technical problem to be solved by this invention is to provide a product for detecting SNP molecular markers related to the litter weight trait of Large White pigs and its application in early screening of piglet growth and development.

[0013] The technical solution adopted by this invention to solve its first technical problem is the application of products that detect SNP molecular markers related to the birth litter weight trait of Large White pigs in the breeding of sows with birth litter weight trait; wherein, the SNP molecular marker is an A>G base mutation located at the nucleotide site 116767089 on chromosome 2 of the international pig genome Sscrofa 11.1 within the DCP2 gene.

[0014] Among them, A>G base mutation refers to the single nucleotide polymorphism variation at this site. It can be genotyped by allele-specific PCR or probe hybridization. This mutation leads to changes in gene function, thereby affecting reproductive traits and is genetically related to litter weight of sows.

[0015] Specifically, by detecting the genotype at locus 116,767,089 within the DCP2 gene, an individual's genetic potential can be directly determined. When this locus is the G allele, it indicates the presence of a dominant genotype associated with high birth weight. The detection product specifically identifies this mutation site, enabling early screening at the DNA level. Molecular detection based on this marker can accurately distinguish between GG, GA, and AA genotypes, providing a genetic basis for breeding decisions and avoiding reliance on later phenotypic observations.

[0016] Furthermore, the nucleotide sequence of the SNP molecular marker is shown in SEQ ID No. 1;

[0017] The product includes at least an upstream primer and a downstream primer, the nucleotide sequence of the upstream primer is shown in SEQ ID No. 2, and the nucleotide sequence of the downstream primer is shown in SEQ ID No. 3.

[0018] Furthermore, the method of application includes the following steps:

[0019] 1) Detect the SNP molecular markers in replacement breeding sows;

[0020] 2) Individuals with the GG or GA genotype at the 116767089th nucleotide site on chromosome 2 of the Sscrofa 11.1 version of the international swine genome, as detected in step 1), will be selected as breeding sows; individuals with the GG genotype at the 116767089th nucleotide site on chromosome 2 of the Sscrofa 11.1 version of the international swine genome can effectively increase the litter weight of sows.

[0021] In some specific embodiments, during the selection of sows for reproductive traits, genomic DNA is first extracted from the individuals to be tested. A detection product containing specific primer pairs is used to amplify the target SNP locus, and the allele genotype of locus 116,767,089 is determined through genotyping. When the test result is a GG or GA genotype, it indicates that the individual carries the dominant allele G, which is associated with high litter weight. Such individuals are preferentially selected for the breeding population. Through continuous screening over multiple generations, the distribution frequency of the dominant allele in the population is gradually increased, thereby stably improving the litter weight of sows at the genetic level.

[0022] The technical solution adopted by this invention to solve its second technical problem is the application of products containing SNP molecular markers related to the litter weight trait in Large White pigs in the breeding of high-yielding litter weight sow breeds; wherein the SNP molecular marker is an A>G base mutation located at the nucleotide site 116767089 on chromosome 2 of the international pig genome Sscrofa 11.1 version within the DCP2 gene.

[0023] Furthermore, the method of application includes the following steps:

[0024] 1) Detect the SNP molecular markers in replacement breeding sows;

[0025] 2) Select individuals with the GG or GA genotype at the nucleotide site at chromosome 2, 116767089 of the international pig genome Sscrofa 11.1 version obtained in step 1) as breeding sows, and mate these breeding sows;

[0026] 3) Test the SNP molecular markers of the sows born from mating in step 2), retain individuals with the GG or GA genotype at the 116767089 nucleotide allele on chromosome 2 of the Sscrofa 11.1 international pig genome, and cull individuals with the AA genotype at the 116767089 nucleotide allele on chromosome 2 of the Sscrofa 11.1 international pig genome. Use these individuals for breeding to cultivate a high-yielding litter weight breeding sow breed with high reproductive performance.

[0027] By detecting specific SNP sites within the DCP2 gene, it is possible to directly determine whether sows carry the G allele associated with high birth litter weight. The DCP2 gene encodes an uncapping enzyme involved in regulating oocyte maturation and embryonic development; the G allele at this site may affect embryo survival by enhancing mRNA degradation efficiency. During detection, specific primers are used to amplify the target region, and genotyping is performed using probe hybridization or sequencing technology to ensure accuracy. The screening step, based on dominant inheritance effects, retains individuals carrying at least one G allele, thereby increasing the frequency of dominant alleles at the population level. This method, by targeting key gene sites controlling embryonic development, avoids the interference of environmental factors on low-heritability traits in traditional breeding, achieving early and precise genotype-based selection.

[0028] The technical solution adopted by this invention to solve its third technical problem is the application of products that detect SNP molecular markers related to the birth litter weight trait in Large White pigs in improving the birth litter weight trait in sow populations; wherein the SNP molecular marker is an A>G base mutation located at the nucleotide site 116767089 on chromosome 2 of the international pig genome Sscrofa 11.1 within the DCP2 gene.

[0029] Furthermore, the method of application includes the following steps:

[0030] 1) Detect the SNP molecular markers in replacement breeding sows;

[0031] 2) Select individuals with the GG or GA genotype at the nucleotide site at chromosome 2, 116767089 of the international pig genome Sscrofa 11.1 version obtained in step 1) as breeding sows, and mate these breeding sows;

[0032] 3) Detect the SNP molecular markers in the sows born from mating in step 2). Retain individuals with the GG or GA genotype at the 116767089th nucleotide allele on chromosome 2 of the Sscrofa 11.1 genome, and cull individuals with the AA genotype at the 116767089th nucleotide allele on chromosome 2 of the Sscrofa 11.1 genome. Breed these individuals to increase the frequency of the dominant G allele at the 116767089th nucleotide allele on chromosome 2 of the Sscrofa 11.1 genome generation by generation, thereby improving the litter weight trait of the sow population and increasing the litter weight of the sow population.

[0033] Among them, the dominant allele G refers to the genotype that carries the G base at this SNP site. Specifically, individuals with the GG or GA genotypes can be screened out through genotyping. The enrichment of this allele can promote the genetic improvement of litter weight traits in sow populations.

[0034] Among them, the population genetic improvement strategy refers to continuously screening individuals with superior genotypes over multiple generations. Specifically, it can be achieved by combining breeding with offspring genotype testing to gradually increase the frequency of superior alleles in the population.

[0035] Specifically, by detecting the genotype of this SNP molecular marker, replacement sows carrying the GG or GA genotype are preferentially selected for breeding. Genotype testing is continuously performed on the offspring, eliminating individuals carrying the AA genotype and retaining those with the dominant genotype for the next breeding cycle. Through the cyclical implementation of this strategy, the distribution frequency of the dominant allele G in the population shows a progressively increasing trend across generations, thereby achieving targeted improvement of litter weight traits in the sow population at the genetic level.

[0036] The technical solution adopted by this invention to solve its fourth technical problem is the application of products that detect SNP molecular markers related to the litter weight trait of Large White pigs in the early screening of piglet growth and development. The SNP molecular marker is an A>G base mutation located at the nucleotide site 116767089 on chromosome 2 of the Sscrofa 11.1 version of the international pig genome within the DCP2 gene. The application involves identifying the genotype of the SNP molecular marker in candidate piglets. When the allele at the nucleotide site 116767089 on chromosome 2 of the Sscrofa 11.1 version of the international pig genome is GG or GA, the candidate piglet is retained for further breeding.

[0037] Genotyping refers to determining the base composition of a target site through nucleic acid extraction, primer design and amplification, and typing detection techniques. Specifically, it can be achieved using Sanger sequencing or high-throughput sequencing platforms. Its role is to quickly distinguish between individuals with GG, GA, and AA genotypes, providing molecular evidence for early breeding.

[0038] Early screening refers to genotyping of piglets before weaning or in the early stages of growth. Specifically, ear tissue samples can be collected within 1-3 weeks after birth. Its purpose is to shorten the breeding cycle and avoid relying on the long-term phenotypic data accumulation required for traditional reproductive performance observation.

[0039] Specifically, this technical approach involves collecting DNA samples from candidate piglets and performing genotypic analysis at locus 116,767,089 on chromosome 2 within the DCP2 gene. A GG or GA genotype indicates that the individual carries at least one dominant allele (G), significantly associated with high litter weight, and is therefore retained for further breeding. An AA genotype indicates that the individual does not carry a dominant allele and can be culled earlier. This screening mechanism allows for genetic advantage assessment before piglets enter the reproductive stage, shortening the screening time by at least one generation compared to traditional methods that require waiting for sows to farrow and measure phenotypic data. Furthermore, by continuously selecting individuals with the GG or GA genotype, the frequency of the dominant allele G in the population will gradually increase, thereby systematically improving the litter weight trait.

[0040] In this invention, the product refers to a reagent or kit. The reagent or kit amplifies the sequence containing the molecular genetic marker nucleotide site using primers, and typically obtains its genotype through sequencing.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] This invention identifies molecular genetic markers associated with litter weight in sows, facilitating targeted improvement of litter weight performance. Utilizing these molecular genetic markers, the litter weight performance of breeding sows can be efficiently assessed, improving the accuracy and convenience of testing. Through genotypic selection, these markers can optimize breeding strategies, improving the birth quality and quantity of piglets, providing technical support to core breeding farms, and contributing to more efficient and precise genetic improvement. This invention, through the discovery and application of molecular genetic markers, provides a novel method for improving litter weight performance in multiple sow breeds, contributing to enhanced overall economic efficiency and the scientific rigor of genetic improvement in the pig industry. Attached Figure Description

[0043] Figure 1 Manhattan plot of genome-wide association analysis for different litter weights of sows.

[0044] Figure 2 QQ plot of genome-wide association analysis for different models of litter weight in sows;

[0045] Where a is the GLM model; b is the FarmCPU model; and c is the BLINK model.

[0046] Figure 3 This is a diagram showing linkage disequilibrium at SNP sites.

[0047] Figure 4 This is a graph showing the association between different alleles at SNP loci and birth weight. Detailed Implementation

[0048] Many specific details of the invention are set forth in the following description to enable those skilled in the art to implement and fully understand the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make various modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Unless otherwise specified, the reagents and other materials used in this embodiment are all commercially available products.

[0051] Example 1: Screening of SNP molecular markers related to litter weight in sows

[0052] 1. Material screening and phenotypic recording

[0053] We collected 1938 purebred Large White pigs from Jiangxi Jiada Group, totaling 7510 breeding records from 2019 to 2024. We also collected litter weight phenotypic data, with a minimum of 3, a maximum of 34, a mean of 16.76, a standard deviation of 4.52, and a coefficient of variation of 26.94%.

[0054] 2. SNP chip detection and genotyping

[0055] 2.1 DNA Sample Extraction and Quality Control

[0056] DNA was extracted from tissue samples using a magnetic bead method. The concentration of DNA samples was detected using a Qubit real-time fluorescence instrument; the integrity of DNA samples was detected by 1% agarose gel electrophoresis, and samples that passed quality control were used for library preparation.

[0057] 2.2 SNP chip testing

[0058] SNP genotyping was performed using the Compson "Zhongxin-1" chip. This chip contains 52,720 SNP loci, integrating genetic differences from multiple pig breeds and covering the entire pig genome. The chip detection process includes DNA sample preparation, denaturation, whole-genome amplification, DNA fragmentation, precipitation and resuspending, hybridization with the chip, extension, chip scanning, and finally, software genotyping output. Genome Studio software was used to visualize the chip data and obtain genotypic data.

[0059] 3. Genome-wide association analysis to locate target SNP loci.

[0060] 3.1 Genome-wide association analysis

[0061] Genome-wide association analysis (GWA) was performed on the material data from chip testing using GAPIT3 (Wang J, Zhang Z. GAPIT version 3: boosting power and accuracy for genomic association and prediction[J]. Genomics, proteomics & bioinformatics, 2021, 19(4): 629-640.). Three statistical models were used: General Linear Model (GLM), Fixed-Stochastic Model Cyclic Probability Unified Model (FarmCPU), and Bayesian Information and Linkage Disequilibrium Iterative Nested Keyway Model (BLINK). Principal components were added as covariates to the models for correction. GWA analysis was performed on the collected birth weight phenotypic traits. Manhattan plot and QQ plot are shown below. Figure 1 and Figure 2 The significance threshold is the logarithm of the Bonferroni-corrected P-value (p=0.05 / N, where N is the number of SNPs) minus log10, which is used to calculate the significantly associated SNP sites.

[0062] 3.2 Discovering significant marker sites

[0063] Across the entire genome, using three GWAS methods, one significant marker locus was located in the litter weight phenotypic trait. The genomic location of the significant SNP locus located by GWAS is chromosome 2, position 116767089 in the international swine genome Sscrofa version 11.1. This SNP locus falls within the DCP2 gene. Figure 3 As shown. Looking at the GWAS results for this SNP locus, the p-values ​​calculated by the GLM, FarmCPU, and BLINK statistical models were 3.49 × 10⁻⁶. -7 ( Figure 2 a) 7.84×10 -7 ( Figure 2 b) and 8.17×10 -7 ( Figure 2 c) The beta effect values ​​were 0.527, 0.434 and 0.444, respectively, with a positive direction, indicating that the GG allele was the favorable allele.

[0064] Example 2: Detection of SNP molecular markers related to litter weight in sows

[0065] This example demonstrates the design of upstream and downstream primers for detecting the A / G nucleic acid site at 116767089 bp on chromosome 2 of the SNP site (International Pig Genome Sscrofa 11.1 version) obtained in Example 1.

[0066] 1. Primer design for the target gene sequence

[0067] The target gene is the sequence within 1000 bp before and after the SNP site at position 116767089 on chromosome 2 of the international pig genome Sscrofa version 11.1. Its nucleotide sequence is as follows:

[0068]

[0069] Sequencing primer pairs were designed using BatchPrimer3 based on the target gene sequence. The primers were synthesized by Invitrogen. The sequencing primer pairs are as follows:

[0070] Upstream primer: 5'-TCCTCCACCTTGCTTATTCATTCT-3' (SEQ ID No. 2)

[0071] Downstream primer: 5'-CTTCTGGTTTCTGTCTTCCCTTTT-3' (SEQ ID No. 3)

[0072] 2. Large White pig genome extraction

[0073] Tissue samples were collected from the Large White pigs to be tested, genomic DNA was extracted, and after quality and concentration testing, the samples were stored at -20℃ for later use.

[0074] 3. PCR amplification of SNP loci associated with litter weight in Large White pigs

[0075] Using the extracted DNA as a template, PCR amplification was performed using the primers described above.

[0076] Amplification system: 10 μL of 2× SuperReal PreMix Plus, 8 μL of ddH2O, 0.5 μL each of upstream and downstream primers (10 μM concentration), and 1 μL of cDNA template.

[0077] Amplification procedure:

[0078] Pre-denaturation at 95℃ for 15 minutes;

[0079] Denaturation at 95°C for 20 seconds; annealing at 58°C for 20 seconds; extension at 72°C for 20 seconds; repeat 40 cycles; extension at 72°C for 5 minutes.

[0080] After amplification, the temperature was maintained at 4°C to preserve the product and terminate the reaction.

[0081] 4. Sequencing and analysis of amplified products

[0082] The PCR products were detected by agarose gel electrophoresis, and the amplified products were then sequenced to obtain their sequences. The sequencing results of these amplified products were compared and analyzed with relevant gene fragments from Large White pigs in GenBank to determine whether the genotype of the target SNP locus related to litter weight was GG, GA, or AA.

[0083] Example 3: Validation of the molecular genetic markers of this application

[0084] To further validate the identified SNP locus significantly associated with litter weight—locus 116767089 on chromosome 2 of the international porcine genome Sscrofa version 11.1—a large population with no genetic exchange with the GWAS population was used for validation. Data from a resequencing population of 560 Large White pigs from the Shaanxi Shunxin Large White breeding farm (average sequencing depth 15.6x) were used to detect the target SNP marker. The association between marker genotype and phenotype was analyzed, and the T-test was used to compare different genotypes.

[0085] The results showed that: Figure 4 As shown, the Sscrofa 11.1 version of the international pig genome, chromosome 2, nucleotide locus 116767089, reveals three genotypes (AA, AG, and GG) in a population of 560 Large White pigs. The average litter weight of AA-type Large White pigs was 18.18 kg; the average litter weight of AG-type Large White pigs was 18.66 kg; and the average litter weight of GG-type Large White pigs was 19.31 kg. The litter weight of GG-type Large White pigs differed significantly from that of AA-type pigs. p =0.0095), which is also significantly different from the GA type ( p =0.0153).

[0086] Example 4: A method for genetic improvement of sows with high litter weight.

[0087] The specific steps in this embodiment are as follows:

[0088] 1) SNP molecular markers related to litter weight were detected in replacement breeding pigs, genomic DNA was extracted, and the primers and methods described in Example 2 above were used for detection;

[0089] 2) Select individuals with the genotype GG or GA as breeding pigs, and mate the selected boars and sows;

[0090] 3) Perform SNP molecular marker testing on piglets born after mating, retain individuals with the genotype GG or GA, and cull individuals with the genotype AA, thereby cultivating a high-fertility, high-livestock pig breed.

[0091] Furthermore, steps (2) and (3) can be repeated based on step (3) to select breeding pigs with genotypes GG or GA generation by generation, eliminate individuals with genotype AA, and gradually increase the frequency of the allele G at this SNP locus in the pig population, thereby increasing the litter weight of offspring pigs.

[0092] Example 5: A method for early screening and selection of piglet growth and development.

[0093] The specific steps in this embodiment are as follows:

[0094] 1) SNP molecular markers related to litter weight were detected in piglets, genomic DNA was extracted, and the primers and methods described in Example 2 above were used for detection;

[0095] 2) Select individuals with genotypes GG or GA for further breeding and mating, and iterate continuously to increase the frequency of allele G, thereby increasing the birth weight of offspring piglets.

[0096] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. The application of a product for detecting SNP molecular markers related to the litter weight trait in Large White pigs in the breeding of Large White sows; the SNP molecular marker is located in the DCP2 gene at nucleotide site 116767089 on chromosome 2 of the international pig genome Sscrofa 11.1 version, and has an A>G base mutation; the product includes at least an upstream primer and a downstream primer, the nucleotide sequence of the upstream primer is shown in SEQ ID No. 2, and the nucleotide sequence of the downstream primer is shown in SEQ ID No.

3.

2. The application according to claim 1, characterized in that, The method of application includes the following steps: 1) Detect the SNP molecular markers in replacement breeding sows; 2) Select individuals with the GG or GA genotype at the nucleotide site at chromosome 116767089 of the international pig genome Sscrofa 11.1 version obtained in step 1) to increase the birth litter weight of sows.

3. Application of products containing SNP molecular markers associated with birth litter weight in Large White pigs in the breeding of high birth litter weight Large White sow breeds; the SNP molecular marker is located in the DCP2 gene at nucleotide site 116767089 on chromosome 2 of the international pig genome Sscrofa version 11.1, and contains an A>G base mutation; the product includes at least an upstream primer and a downstream primer, the nucleotide sequence of the upstream primer is shown in SEQ ID No. 2, and the nucleotide sequence of the downstream primer is shown in SEQ ID No.

3.

4. The application according to claim 3, characterized in that, The method of application includes the following steps: 1) Detect the SNP molecular markers in replacement breeding sows; 2) Select individuals with the GG or GA genotype at the nucleotide site at chromosome 2, 116767089 of the international pig genome Sscrofa 11.1 version obtained in step 1) as breeding sows, and mate these breeding sows; 3) Test the SNP molecular markers of the sows born from mating in step 2), retain individuals with the GG or GA genotype at the 116767089 nucleotide site, and cull individuals with the AA genotype at the 116767089 nucleotide site. Then breed them to cultivate a high-birth-weight, high-reproductive-performance sow breed.

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