阅读说明：本技术 一种snp分子标记在鉴定高繁殖性能奶牛及辅助育种中的应用 (Application of SNP molecular marker in identification of high-reproductive-performance dairy cows and auxiliary breeding ) 是由 王金鹏 黄金明 鞠志花 杨春红 高运东 刘文浩 肖遥 张亚冉 魏晓超 高亚平 姜 于 2021-09-15 设计创作，主要内容包括：本发明涉及一种SNP分子标记在鉴定高繁殖性能奶牛及辅助育种中的应用,属于生物化学遗传育种技术领域,具体通过牛50K SNP芯片和全基因组关联分析的方法提供了SIGLEC12基因作为奶牛妊娠期标记基因的应用,并通过分子生物学相关技术提供了SIGLEC12基因第七外显子的一组单倍型的信息,可用于选择具有优势妊娠周期基因型的奶牛个体。养殖企业通过选择优势基因型个体留种,可以提高SIGLEC12基因妊娠周期优势基因型在奶牛群体中的频率,从而优化奶牛群体的妊娠周期,提高奶牛的繁殖效率,降低养殖成本,增加经济效益。本发明为加速奶牛的妊娠周期遗传改良提供了一种新的方法。(The invention relates to an application of SNP molecular markers in identification of high-reproductive-performance dairy cows and auxiliary breeding, belongs to the technical field of biochemical genetic breeding, and particularly provides an application of SIGLEC12 gene as a marker gene of the dairy cows in gestation period by a method of carrying out correlation analysis on a 50K SNP chip of a cow and a whole genome, provides information of a group of haplotypes of a seventh exon of SIGLEC12 gene by a molecular biology correlation technology, and can be used for selecting dairy cows with dominant gestation period genotypes. By selecting the dominant genotype individual for seed reservation, breeding enterprises can improve the frequency of the dominant genotype of the SIGLEC12 gene pregnancy period in the dairy cow population, thereby optimizing the pregnancy period of the dairy cow population, improving the breeding efficiency of the dairy cows, reducing the breeding cost and increasing the economic benefit. The invention provides a new method for accelerating the genetic improvement of the pregnancy period of the dairy cow.)

1. An SNP molecular marker is characterized in that the nucleotide sequence of the molecular marker is shown as SEQ ID No.4, the mononucleotide site at the 481bp position of the sequence is T or G, the mononucleotide site at the 485bp position is G or A, and the mononucleotide site at the 531bp position is C or T.

2. The primer for detecting the SNP molecular marker according to claim 1, wherein the sequence of the upstream primer is shown as SEQ ID No.2, and the sequence of the downstream primer is shown as SEQ ID No. 3.

3. A kit comprising the primer of claim 2.

4. The kit of claim 3, further comprising one or more of a sampling tool, a genomic DNA extraction reagent, or a PCR reagent.

5. The use of the SNP molecular markers according to claim 1 for identifying high reproductive performance cows.

6. The application of the SNP molecular marker in identifying high reproductive performance dairy cattle according to claim 5, wherein the combination of three SNP loci G. +3401T > G, G. +3405G > A, G. +3451C > T on the SIGLEC12 gene is a GAT haplotype which is a dominant haplotype of the pregnancy cycle trait of the dairy cattle.

7. The use of the SNP molecular marker of claim 5 for identifying high reproductive performance cows, wherein the cows are one of Chinese Holstein cows, Sanhe cows, Xinjiang brown cows or grassland red cows; preferably, the SNP molecular marker is used for identifying Chinese Holstein cows with high breeding performance;

preferably, the breeding performance comprises mating rate, conception rate, non-return rate, mating index, calving rate, calving index, calf survival rate and breeding survival rate; further, the cows of the GAT haplotype phenotype have a shorter gestation period.

8. The use of the detection primer of the SNP molecular marker according to claim 2 and the kit according to claim 3 for identifying high-breeding Chinese Holstein cows or assisting breeding of Chinese Holstein cows.

9. A method for identifying Chinese Holstein cows with high breeding performance is characterized in that:

(1) extracting the genome DNA of the Chinese Holstein cow to be detected;

(2) amplifying the 7 th exon of the SIGLEC12 gene of the Chinese Holstein cow by using the genome DNA of the step (1) as a template and utilizing the primer pair of the second aspect through PCR reaction;

(3) and detecting a PCR amplification product, wherein if the mononucleotide site at the 481bp position of the sequence in the amplification sequence is G, the mononucleotide site at the 485bp position is A, the mononucleotide site at the 531bp position is T and the genotype is GAT, the cattle to be detected belongs to the Chinese Holstein cow with high reproductive performance.

10. An auxiliary breeding method of Chinese Holstein cows, which comprises adopting the Holstein cow individual with the dominant haplotype obtained by the identification method of claim 9 as a parent to breed.

Technical Field

The invention belongs to the technical field of dairy cow breeding markers, and particularly relates to an SNP molecular marker, a primer sequence for detecting the SNP molecular marker, a kit containing the primer sequence, and applications of the SNP molecular marker, the primer and the kit in identification of high-reproductive-performance dairy cows and auxiliary breeding.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

With the increasing world population, the Food and Agriculture Organization (FAO) of the united nations predicted that the global demand for human consumption of milk would increase by 50% by 2050. Dairy production systems have proposed a series of selection methods for increasing milk yield and reducing land cost, management cost, etc. for decades, and the breeding of cows tends to be more intensive. However, with the high milk yields of intensive farming, more and more animal health problems arise, in particular reproductive problems, such as quiet or no oestrus, reduced postpartum ovarian activity, reduced conception rates, increased culling and mortality rates, and a gradual reduction in the reproductive capacity of cows as a whole (Gaddis et al, 2016; Gutierrez-Reiinoso et al, 2021).

Good reproductive performance is a key factor in the profitability-hurting of dairy production systems (Shallo et al, 2014). Calving intervals are often used as an indicator to evaluate reproductive performance in cows (Roche et al, 2017). Calving intervals are a complex trait with low heritability (Berry et al, 2014), meaning that only a small fraction of phenotypic variation is explained by measurable additive genetic variances (Berry and Evans, 2014). In contrast, the pregnancy cycle has a moderate heritability of 0.33-0.62 (Hansen et al, 2004; Norman et al, 2009), meaning that relatively accurate predictions of phenotypes can be achieved if a significant proportion of additive genetic variations in the pregnancy cycle can be predicted. Since the segregation of homologous chromosomes is relatively random during gametogenesis, it is not possible to achieve highly accurate predictions of genetic merit based solely on pedigree information. Thus, the prediction based on genotype results in a more accurate genetic estimate that can be used as an index to evaluate the reproductive performance of cows.

The gestational cycle measures the critical stages in the development of the mammal's fetus from pregnancy to delivery. Events occurring during the gestational period have important effects on the health, productivity and fertility of the offspring. Abnormalities in the pregnancy cycle will lead to premature or overdue birth, leading to acute and long-term health problems. The gestational period is highly correlated with health, productivity and reproductive performance. Prolonged gestational periods can lead to increased fetal weight, decreased pregnancy rates, and dystocia (Vieira-Neto et al, 2017). The breeding efficiency of the dairy cows with short pregnancy periods in a reasonable range is higher, which means lower feeding cost and management cost, more efficient calving capacity and higher income for pastures. 25 SNP sites identified in the holstein cattle population, which are significantly related to the gestational cycle, are distributed in 6 QTL regions, with the most significant SNP site located downstream of ZNF613 gene of chromosome 18, accounting for 1.37% of genetic variation (Purfield et al, 2019).

The study shows that the pregnancy period of 274-281 days is optimal for the Holstein cattle group, the milk yield is maximized, and the calving difficulty and the perinatal mortality are minimized. In the Holstein cattle population in China, a space for optimizing the pregnancy cycle still exists. However, the genetic mechanism of the bovine gestational cycle is less researched, and the development work of related molecular markers needs to be strengthened. A whole genome association analysis method (GWAS) is a powerful means for analyzing a complex trait genetic mechanism and positioning key candidate molecular marker loci, and plays an important role in analyzing the mass trait and quantitative trait genetic mechanisms of model species and non-model species. Sialic acid binding immunoglobulin-like lectin 13(SIGLEC12) belongs to the cell surface protein family of the immunoglobulin superfamily. They mediate protein-carbohydrate interactions by selectively binding different sialic acid fragments on glycolipids and glycoproteins. The SIGLEC12 gene is obviously related to the calving character of Holstein cows, and the prior research shows that the SIGLEC12 gene is expressed in human placenta.

Disclosure of Invention

Based on the research background, the invention aims to provide a genetic improvement method for shortening the bovine gestation period. The existing research shows that the SIGLEC12 gene is obviously related to the calving character of Holstein cows and possibly participates in the initiation of parturition. According to the invention, the SIGLEC12 gene is used as a candidate gene of the pregnancy cycle of the dairy cow, the correlation between the mutation site and the breeding traits of the dairy cow is researched, and the following technical scheme is obtained:

the invention firstly provides an SNP molecular marker, and the nucleotide sequence of the molecular marker is shown as SEQ ID NO:4, the mononucleotide site at the 481bp position of the sequence is T or G, the mononucleotide site at the 485bp position is G or A, and the mononucleotide site at the 531bp position is C or T.

The method for improving the gestation period of the cow population comprises the following steps: molecular markers related to the periodic characters of the dairy cows in the gestational period are obtained by a PCR method. In further research, the invention provides a SIGLEC12 gene related to the cow gestational cycle character by a PCR method, and 3 SNP sites are identified on the 7 th exon of the gene by a Bovine SNP50 chip to form 1 haplotype. In a Holstein cattle population, the genotype of 3 SNP of the 7 th exon of the SIGLEC12 gene is associated with the breeding value of the long and short gestational period genome of cattle of the population, and the analysis result shows that the haplotype is obviously related to the gestational period of the cows. According to the identification result of the SNP locus, breeding personnel can select favorable haplotype individuals for seed reservation, thereby improving the pregnancy cycle character of the cow group and improving the propagation efficiency.

The SNP identification method adopted by the invention is as follows: genotyping is carried out in a cow population by a Bovine SNP50 chip, 3 SNP sites (chr18: g.57591390T > G, chr18: g.57591394G > A, chr18: g.57591440C > T) exist on the 7 th exon of the SIGLEC12 gene (the coordinate position of the SNP sites is based on the Bovine reference genome UMD3.1 as a standard) (figure 1), and the mutation sites are completely linked to form a haplotype combination TGC/GAT; correlation analysis of the estimated breeding value of the genotype of the cow population and the genome of the cow pregnancy cycle proves that the haplotype combination is obviously related to the cow pregnancy cycle.

Based on the research results, the SNP molecular marker in the 7 th exon of the SIGLEC12 gene can be used as a marker for identifying high reproductive trait cows and assisting breeding, can be used for screening parent individuals with shorter gestation period, effectively shortens the breeding period and saves the breeding resources. In addition, the related detection reagent of the molecular marker can be developed into related products for breeding Chinese Holstein cows.

The beneficial effects of one or more technical schemes are as follows:

1. the invention utilizes the information of 3 SNP loci on the 7 th exon of the cattle SIGLEC12 gene and adopts the related technology of molecular biology to identify the genotypes of the cows at the 3 loci, thereby realizing the early selection of the genotype individuals with short gestation period.

2. The invention identifies 1 group of haplotypes consisting of 3 SNP combinations, detects the genotype of the SIGLEC12 gene of an individual cow at the site by a molecular biology correlation technique, selects favorable haplotype individual seed reservation by correlation analysis of estimated breeding values of the pregnancy cycle characters of the cow, and can improve the frequency of the SIGLEC12 gene short-term genotype in a cow group, thereby improving the breeding efficiency of the cow group, reducing the feeding cost of a pasture and improving the breeding benefit. The invention provides a new method for genetic improvement of the pregnancy period of the dairy cow.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 shows the sequencing results of 3 SNP sites on exon 7 of SIGLEC12 gene;

FIG. 2 is a schematic representation of the amino acid sequence and predicted secondary structure of the wild type of the bovine SIGLEC12 gene;

FIG. 3 is a schematic diagram of the amino acid sequence and predicted secondary structure of the mutant form of bovine SIGLEC12 gene.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As introduced in the background technology, the length of the gestation period is related to a plurality of indexes of health, production capacity and the like of offspring, and shortening the gestation period within a reasonable range can effectively improve the breeding efficiency of the dairy cows and reduce the feeding cost. In order to realize the genetic improvement breeding of the cattle in the period of pregnancy shortening, the invention screens the molecular markers related to the cattle in the period of pregnancy, confirms that the haplotype consisting of 3 SNPs on the 7 th exon of the SIGLEC12 gene is related to the period of pregnancy of the cow, can be used as an auxiliary breeding marker, and improves the breeding efficiency of the cow. Based on the results, the invention provides the application of the SNP molecular marker in identifying the Chinese Holstein cow with high reproductive performance and assisting in breeding.

In the first aspect of the invention, an SNP molecular marker is provided, the nucleotide sequence of the molecular marker is shown as SEQ ID NO.4, the mononucleotide site at the 132bp position of the sequence is T or G, the mononucleotide site at the 136bp position is G or A, and the mononucleotide site at the 182bp position is C or T.

According to the research result of the invention, the SNP site chr18: g.57591390T > G on the 7 th exon of the SIGLEC12 gene belongs to synonymous mutation, and both the wild-type codon TCT and the mutant codon TCG code serine (S). The SNP locus chr18: g.57591394G > A belongs to missense mutation, the wild codon GAG where the mutation belongs encodes glutamic acid (E), and the mutant codon AAG encodes lysine (K); SNP site chr18: g.57591440C > T belongs to missense mutation, and the wild type codon GCG in which the mutation type codon GCG codes alanine (A) and the mutation type codon GTG codes valine (V).

In the second aspect of the invention, the primer for detecting the SNP molecular marker of the first aspect has an upstream primer sequence shown as SEQ ID NO.2 and a downstream primer sequence shown as SEQ ID NO. 3.

The SNP molecular marker of the first aspect is positioned in the 7 th exon of the SIGLEC12 gene, and the nucleotide sequence of the 7 th exon is shown as SEQ ID NO. 1. The SNP molecular marker of the first aspect of the invention is an amplification product obtained by amplifying the 7 th exon of bovine SIGLEC12 gene by means of PCR, and the sequence of the amplification product is shown as SEQ ID NO.4 or SEQ ID NO. 5, and the size is 421 bp.

In the SNP molecular marker, the sequence shown by SEQ ID NO.4 represents the dominant trait, and the sequence shown by SEQ ID NO. 5 represents the inferior trait.

In a third aspect of the invention, a kit comprising the primer of the second aspect.

Preferably, the kit further comprises one or more of a sampling tool, a genomic DNA extraction reagent or a PCR reaction reagent.

In a fourth aspect of the invention, the application of the SNP molecular marker of the first aspect in identifying cows with high reproductive performance is provided.

Preferably, the SNP molecular marker is a combination of the three SNP sites, and the SNP sites are located at the 3401bp, the 3405bp or the 3451bp bases of the SIGLEC12 gene sequence; wherein, the base at the 3401bp is G, the base at the 3401bp is A or the base at the 3451bp is T, namely G. +3401T > G, G. +3405G > A, G. +3451C > T; in the scheme with better effect, the combination of the loci is haplotype GAT as a marker with high breeding performance. When the SIGLEC12 gene sequence shows that the GAT haplotype is the dominant haplotype of the cow gestational period character.

Preferably, the cow is one of a Chinese Holstein cow, a Sanhe cow, a Xinjiang brown cow or a grassland red cow. In a further preferred scheme, the SNP molecular marker is used for identifying Chinese Holstein cows with high breeding performance.

The breeding performance of the livestock in the field comprises mating rate, conception rate, non-return rate, mating index, calving rate, calving index, calf survival rate, breeding survival rate and the like. In the scheme of the fourth aspect, the high reproductive performance specifically refers to the length of the gestation period of the Chinese Holstein cow, and it should be clear that the SNP molecular marker is used for identifying the cow with a reasonable and short gestation period, and the cow with the GAT haplotype phenotype has a shorter gestation period.

In the fifth aspect of the invention, the detection primer of the SNP molecular marker in the second aspect and the application of the kit in the fourth aspect in identifying the Chinese Holstein cow with high breeding performance or assisting in breeding the Chinese Holstein cow are provided.

The sixth aspect of the invention provides a method for identifying Chinese Holstein cows with high breeding performance, which is characterized by comprising the following steps:

(1) extracting the genome DNA of the Chinese Holstein cow to be detected;

(2) amplifying the 7 th exon of the SIGLEC12 gene of the Chinese Holstein cow by using the genome DNA of the step (1) as a template and utilizing the primer pair of the second aspect through PCR reaction;

(3) detecting a PCR amplification product, wherein if the amplification sequence comprises the SNP molecular marker of the first aspect, the cattle to be detected belongs to individuals with high reproductive performance.

In a preferred scheme, when the genotypes of the 481bp, 485bp and 531bp in the amplification sequence are GAT, the high-reproduction-performance individual is judged.

The seventh aspect of the invention provides an auxiliary breeding method for Chinese Holstein cows, which comprises breeding by using the Holstein cow individual of which the dominant haplotype is obtained by the identification method of the sixth aspect as a parent.

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.

Example 1

The exon 7 affecting SIGLEC12 gene in cow gestational period and its molecular marker and application are described in detail below.

The invention relates to a 7 th exon affecting SIGLEC12 gene of dairy cows in gestational period, a molecular marker and application thereof, wherein the specific scheme is as follows:

1. screening SIGLEC12 gene as cow gestational period candidate gene

(1) 2709 Holstein cow blood or hair follicle samples were collected in 11 large-scale farms

Samples of Holstein cattle were collected from 11 pastures across the country, and the location of the pasture and the number of samples collected from each pasture are shown in Table 1.

TABLE 1 location of pasture where samples were collected and number of samples collected

The place of pasture	Number of samples	The place of pasture	Number of samples
				Gansu Jinchang	294	Hebei chenchen platform	279
Inner Mongolia Tongliao	399	Persistent branches of Jiangsu	285
				Xinjiang tower city	200	Shandong Dezhou	200
Shandong Linyi	398	Shandong Jinan	94
				Shandong Taian medicine	96	Shandong Ying	268
Guangdong province of Guangdong province	196

(2) The genotype of the collected samples was determined using Illumina bovine snp50 chip. The determination of the genotype was performed by Neuger corporation, and the genotype of 47843 SNP marker sites was obtained in total.

(3) The genomic breeding value for each individual during the gestational period was estimated based on genotype. Genome evaluation breeding values were performed by nyquist corporation.

(4) And performing whole genome correlation analysis on the genome breeding value of the gestational cycle by using GEMMA software based on genotype data, wherein a mixed linear model is used as an analysis model, and the pasture and the bovine month age are used as covariates. Multiple test corrections were performed using the FDR method. The correlation analysis result shows that the most significant 3 SNP sites are positioned on the 7 th exon on the SIGLEC12 gene to form a haplotype, and the significant P value is 2.63E-04.

Identification of haplotype advantageous to exon 7 of SIGLEC12 Gene

Of the 2709 Holstein cattle collected, 2586 individuals with GAT/GAT homozygous haplotypes were identified, with a mean of-0.699 for the cycle-estimated breeding values, 123 individuals with TGC/GAT heterozygous haplotypes, with a mean of-0.024 for the cycle-estimated breeding values, whereas in genomic genetic evaluation, the lower the cycle-genomic breeding value, the better the GAT, the dominant haplotype.

3. Amplification of exon 7 sequence of bovine SIGLEC12 gene

(1) Bovine tail vein blood collection

Cattle with long gestation period and cattle with short gestation period are selected as test materials, and tail vein blood of the cattle is collected.

(2) Genomic DNA extraction

mu.L of whole blood was taken, 500. mu.L of STE lysis buffer was added, 50. mu.L of 10% SDS and 5. mu.L of proteinase K (20mg/ml) were added in this order, and lysis was carried out at 56 ℃ for about 3 hours until the lysate was clear. Add the same volume of saturated phenol (250. mu.L), chloroform/isoamyl alcohol (24:1) (250. mu.L), gently shake for 20min, and centrifuge at 12000rpm for 10 min. And taking the supernatant, and repeating the steps until no protein layer exists between the water phase and the organic phase. And (3) taking the supernatant, adding chloroform/isoamylol with the same volume, shaking gently for 20min, and centrifuging at 12000rpm for 10 min. Collecting supernatant, adding 1/10 volumes of 3MNaAc (pH5.2) and 2 volumes of cold anhydrous ethanol, shaking, standing at-20 deg.C for 20min, and centrifuging at 12500rpm for 20 min. The nucleic acid is precipitated at the bottom of the tube. The supernatant was discarded and the precipitate was washed with 70% ethanol. The precipitate was collected and air dried until the ethanol was completely volatilized. Adding 20. mu.L of TE (containing RNaseA) to dissolve the DNA, standing at 37 ℃ for about 30min, and storing at 4 ℃. Detecting DNA sample by 1% agarose gel electrophoresis, and detecting concentration and purity by ultraviolet spectrophotometer.

(3) Primer design

A pair of specific primers is designed according to the gene sequence of the bovine SIGLEC12 gene (with the GenBank gene accession number of LOC 618463). Wherein the content of the first and second substances,

the forward primer is SIGLEC 12-5F: 5'-GGGCGTGGGACAACTAAC-3'

The reverse primer is SIGLEC 12-3F: 5'-AGGGCTCAGCAGGAAAGG-3', respectively;

(4) complex enzyme chain reaction

The primer is used for PCR amplification, and the reaction system is as follows: 10 Xbuffer 1. mu.L, 2.5mM dNTP 0.8. mu.L, 2.5mM MgCl₂0.6. mu.L, 0.1. mu.L of primer F (10. mu.M), 0.5. mu.L of primer R (10. mu.M), 0.1. mu.L of Taq enzyme (5U/. mu.L), and0.5 μ L plate, 0.7 μ L LCGreen saturated fluorescent dye, plus H₂Make up to 10. mu.L of O. The amplification reaction was performed on an Applied Biosystem PCR system under the following conditions: 5min at 95 ℃; 30s at 95 ℃, 30s at 59 ℃ and 1min at 72 ℃; 35 cycles; 5min at 72 ℃. The haplotypes of the PCR products were determined by Sanger sequencing.

Selecting core group individuals of the dairy cows, detecting genotypes of three sites of SIGLEC12 genes chr18: g.57591390T > G, chr18: g.57591394G > A and chr18: g.57591440C > T by utilizing the related technology of molecular biology, selecting favorable haplotype individuals for reservation, improving the pregnancy period characters of the dairy cow groups, improving the propagation efficiency, reducing the breeding cost, increasing the breeding income and laying a foundation for breeding high-propagation-efficiency new-quality dairy cow strains.

Example 2

The genotype and allele frequency distribution of 3 SNP sites of the 7 th exon of SIGLEC12 in the Holstein cattle population were determined by Sanger sequencing, and the results are shown in Table 2, which includes Holstein cattle in various pastures of our country. The detection result shows that 2 genotypes exist in the Holstein cow population in China; in all populations tested, the frequency of the GAT/GAT haplotype combination was 97.8%, the frequency of the TGC/GAT haplotype combination was 2.2%, and the GAT haplotype was the dominant haplotype (see Table 2).

TABLE 2 results of the distribution of the bovine SIGLEC12 gene in the Holstein cattle population

Table 2 illustrates: the group materials are all the Holstein cattle groups in China, wherein: the group 1 is a Holstein cattle group in a certain pasture in Gansu, the group 2 is a Holstein cattle group in a certain pasture in Hebei, and the group 3 is a Holstein cattle group in a certain pasture in inner Mongolia.

To determine whether the bovine SIGLEC12 haplotype was associated with differences in the bovine pregnancy cycle, 2709 Holstein cattle were selected for correlation analysis of SIGLEC12 haplotype and pregnancy cycle estimated breeding values. The mean genomic breeding value for individuals with the TGC/GAT haplotype was-0.024 and the mean genomic breeding value for individuals with the GAT/GAT haplotype was-0.699. The correlation of different haplotypes with the bovine gestational cycle trait was analyzed using PLINK v1.90 software and the results showed a significant correlation between the haplotype and the genomic breeding value (P value 5.052 e-11).

The invention identifies 1 group of haplotypes consisting of 3 SNP combinations, detects the haplotype of the SIGLEC12 gene of an individual cow at the site by a molecular biology correlation technique, selects favorable haplotype individual seed reservation by correlation analysis of estimated breeding values of the properties of the cow gestational period, and can improve the frequency of the SIGLEC12 gene gestational period dominant haplotype in a cow group, thereby improving the breeding efficiency of the cow group, reducing the feeding cost of a pasture, improving the breeding benefit and providing a new method for genetic improvement of the cow gestational period.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

SEQUENCE LISTING

<110> Shandong province agriculture academy of sciences stockbreeding research institute, Shandong Orxok stock farming Co Ltd

Application of SNP molecular marker in identification of high reproductive performance dairy cow and auxiliary breeding

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