CN117051121B - Chicken FGF2 gene SNP molecular marker, application thereof and detection primer - Google Patents

Abstract

The present invention relates to a chicken FGF2 gene SNP molecular marker and its application and detection primer. The present invention finds through research that a SNP site rs53587229 on the first intron of the chicken FGF2 gene has a T>C mutation. After analysis and verification, the SNP site is significantly correlated with the growth traits, carcass traits and body size traits of chickens, and can be used as a molecular marker for genetic improvement of chicken breeds. The use of the above-mentioned SNP molecular marker to select and breed chickens is conducive to improving the growth traits and/or carcass traits and/or body size traits of the chicken population. The present invention also provides detection primers for detecting the SNP molecular marker of the chicken FGF2 gene, and the PCR product is sequenced to quickly and accurately identify the genotype of the SNP molecular marker, thereby shortening the breeding time and accelerating the breeding process, which has great economic application value and scientific research value.

Description

A chicken FGF2 gene SNP molecular marker and its application and detection primer

Technical Field

The invention relates to a chicken FGF2 gene SNP molecular marker and application and detection primer thereof, belonging to the technical field of biological breeding.

Background Art

In the past 20 years, global poultry production has made great progress. The world's poultry meat consumption has exceeded beef, becoming the second most consumed meat after pork, and the world's poultry consumption will continue to maintain an upward trend. The reason for this phenomenon is inseparable from the rapid development of poultry science. Poultry genetic resources are the material basis for poultry breeding and production. According to statistics, 40% of the great achievements of modern poultry industry are attributed to poultry breeding. At present, modern breeding technology using molecular markers is an important means to accelerate the selection of improved varieties and improve the genetic quality of populations. The application of molecular marker breeding is first to screen and detect genetic markers closely related to the economic traits of livestock and poultry at the DNA level, followed by the establishment of rapid detection methods for their gene polymorphism, and then to achieve genetic marker-assisted selection and early diagnosis and selection.

Single nucleotide polymorphism (SNP) refers to DNA sequence polymorphism caused by the variation of a single nucleotide at the genome level. Studies have found that SNP is an ideal molecular marker due to its richness and high polymorphism. Therefore, the correlation analysis between SNP polymorphism and economic traits can provide auxiliary marker selection for poultry molecular breeding.

Chicken is an important economic poultry and also an important model organism in scientific research. Growth traits, carcass traits and body size traits are important economic traits. Domestic high-quality local chickens generally have the problem of slow growth, which affects economic benefits. Over the years, chicken breeders have conducted a large number of experimental studies to try to find candidate genes and related SNP molecular markers related to the above economic traits of chickens.

FGF2, also known as basic fibroblast growth factor (bFGF) and FGF-β, is a growth factor and signaling protein encoded by the FGF2 gene. FGF2 is a member of the fibroblast growth factor family and regulates the proliferation and differentiation of specific types of cells. In addition, FGF2 exhibits potent angiogenic effects in vivo and in vitro, stimulates the growth of smooth muscle cells, and promotes wound healing and tissue regeneration. FGF2 may also play an important role in the differentiation and function of the nervous system and the regeneration of the eyes and bones. Studies have shown that single nucleotide polymorphisms of the FGF2 gene regulate reproductive traits and milk production traits in dairy cows, but there are no reports on whether single nucleotide polymorphisms of the FGF2 gene are associated with growth traits in poultry.

Summary of the invention

In order to solve the above problems, the first object of the present invention is to provide a FGF2 gene SNP molecular marker, which is significantly correlated with the growth traits and/or carcass traits and/or body size traits of chickens.

The second object of the present invention is to use the SNP molecular marker in the breeding for improving chicken growth traits and/or carcass traits and/or body size traits.

The third object of the present invention is to provide a detection primer for detecting the genotype of the SNP molecular marker.

In order to achieve the above object, the technical solution of a FGF2 gene SNP molecular marker of the present invention is:

A FGF2 gene SNP molecular marker, the nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.1, and the 174th base from the 5' end is C or T.

The beneficial effect of the above technical solution is that the present invention discovers the above SNP molecular marker for the first time, and the SNP molecular marker corresponds to the rs53587229 site in the first intron of the chicken FGF2 gene. The SNP site has not been reported before and is a newly discovered molecular marker.

In order to achieve the above object, the technical solution of the present invention for using a SNP molecular marker in the breeding for improving growth traits and/or carcass traits and/or body size traits of chickens is:

The invention discloses an application of a SNP molecular marker in breeding for improving growth traits and/or carcass traits and/or body size traits of chickens.

The beneficial effect of the above technical solution is that: the present invention discovers a new mutation site on the chicken FGF2 gene. Through association analysis, it is found that the newly discovered SNP site is significantly correlated with the growth traits, body size traits and carcass traits of chickens, and can be used for auxiliary selection and molecular breeding of chickens, which is of great significance for improving the growth traits and/or carcass traits and/or body size traits of chickens.

Specifically, the growth traits include birth weight, 2-week body weight, 4-week body weight, 6-week body weight, 8-week body weight, 10-week body weight and 12-week body weight; the carcass traits include half-eviscerated, fully eviscerated, head weight, claw weight, double-wing weight, liver weight, gizzard weight, spleen weight, pancreas weight, breast muscle weight, leg weight, leg muscle weight, gizzard rate, leg muscle weight rate and body weight after moulting; the body size traits include 8-week shank length, 4-week shank circumference, 8-week shank circumference, 4-week chest width, 4-week sternum length, 8-week sternum length, 12-week sternum length, 4-week body oblique length, 8-week body oblique length and 12-week body oblique length.

As a further improvement, the genotype of the SNP molecular marker is detected. When the genotype of the SNP molecular marker is TT, the chicken to be tested is a high-weight, large-sized individual. When the genotype of the SNP molecular marker is CC, the chicken to be tested is a low-weight, small-sized individual.

The beneficial effect of the above technical solution is that by detecting and analyzing the genotype of the above FGF2 gene SNP molecular marker, the mature weight of chickens can be predicted early and effectively, which can shorten the breeding time and accelerate the breeding process.

As a further improvement, the nucleotide sequence shown in SEQ ID NO.1 is amplified by PCR; the nucleotide sequences of the detection primers amplified by PCR are shown in SEQ ID NOs.2-3.

As a further improvement, the genotype of the SNP molecular marker is detected by gene sequencing the product of the PCR amplification.

The beneficial effect of the above technical solution is that gene sequencing can quickly, effectively and accurately detect the genotype of SNP molecular markers.

In order to achieve the above object, a technical solution of a detection primer of the present invention is:

A detection primer is used to detect the genotype of the SNP molecular marker of the FGF2 gene; the nucleotide sequence of the detection primer is shown in SEQ ID NO.2-3.

The beneficial effect of the above technical scheme is that: the present invention has found through research that the rs53587229 site of the first intron of the chicken FGF2 gene is significantly correlated with the differences in chicken growth traits, carcass traits and body size traits, specifically: the T>C mutation of the rs53587229 site of the FGF2 gene is significantly associated with birth weight, 2-week weight, 4-week weight, 6-week weight, 8-week weight, 10-week weight and 12-week weight (P<0.05), and both show that the weight of individuals with TT and TC genotypes is higher than the corresponding weight of individuals with CC gene. According to the SNP molecular marker, the corresponding detection primers for chicken growth traits and/or carcass traits and/or body size traits are designed, and TT homozygous chicken individuals can be detected and screened out, so the detection primers can be used in auxiliary selection and molecular breeding of chickens, which is helpful to establish a chicken population with excellent genetic resources.

Application of a detection primer in chicken germplasm resource improvement.

The beneficial effect of the above technical solution is that: association analysis found that the SNP molecular marker is significantly correlated with important economic traits of chickens (growth traits, body size traits and carcass traits), so the detection primer is used to amplify the sequence shown in SEQ ID NO.1, and the genotype of the SNP molecular marker is detected by gene sequencing and other means, and chicken individuals with homozygous genotype TT are selected, which can be used for assisted selection and molecular breeding of chickens, and has broad application prospects in the improvement of chicken germplasm resources.

Specifically, it is used in improving chicken weight, tibia length, tibia circumference, chest width, sternum length, oblique body length, half-eviscerated, fully eviscerated, head weight, claw weight, double wing weight, liver weight, gizzard weight, spleen weight, pancreas weight, breast muscle weight, leg weight, leg muscle weight, gizzard rate, leg muscle weight rate and/or weight resources after plucking.

More specifically, in practical application, the type of the 174th nucleotide from the 5' end of the sequence shown in SEQ ID NO.1 is detected, and chicken individuals with homozygous TT at this site are selected to establish a chicken population with excellent genetic resources.

Beneficial effects of the present invention:

The present invention uses 772 Gushi chicken-Anka chicken F2 _generation resource groups as research objects, and conducts a large amount of verification work to find that there is a SNP site on the first intron of the chicken FGF2 gene, and its nucleotide sequence is shown in SEQ ID NO.1, and the 174th base from the 5' end is C or T (TC, rs53587229). Through analysis, it is found for the first time that the SNP site of the FGF2 gene is significantly correlated with chicken growth traits (weight), carcass traits (half-eviscerated, fully eviscerated, head weight, claw weight, double wing weight, liver weight, gizzard weight, spleen weight, pancreas weight, breast muscle weight, leg weight, leg muscle weight, gizzard rate, leg muscle weight rate and weight after molting) and body size traits (tibia length, tibia circumference, chest width, sternum length, body oblique length). The SNP allele T is positively correlated with high body weight traits (growth traits), the allele C is positively correlated with low body weight traits (growth traits), and the phenotypic traits of the heterozygous allele CT are in the middle. Body weight is an important growth trait of chickens, and body size traits such as tibia circumference and body oblique length are significantly correlated with the size of chickens. Moreover, growth traits, carcass traits and body size traits are very important economic traits of chickens. Therefore, using this SNP site as a molecular marker for chicken genetic improvement can lay the foundation for screening out homozygous high-quality local chicken populations, which is of great significance for improving the growth traits and/or carcass traits and/or body size traits of chickens.

The present invention provides a detection primer for the SNP molecular marker of the chicken FGF2 gene. The detection primer is used to perform gene sequencing on the amplified product after PCR amplification to analyze the genotype of the SNP molecular marker. Combining PCR with gene sequencing to analyze the genotype of the SNP molecular marker of the chicken to be tested has the advantages of simple operation, low cost, short cycle, large-scale and high-throughput detection, which can greatly improve the accuracy of SNP site genotype determination and play an important role in improving the growth traits of chickens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an agarose gel electrophoresis diagram of PCR products in Experimental Example 2 of the present invention;

FIG. 2 is a peak diagram of sequencing of individuals with different genotypes in Experimental Example 2 of the present invention.

DETAILED DESCRIPTION

Gushi chicken is a famous local chicken breed in my country. It belongs to the yellow chicken type. It is centered in Gushi County and is naturally formed through long-term closed breeding under special ecological environment and feeding conditions. Gushi chicken has the characteristics of high egg production, large and thick egg shells, and stable genetic performance. It is a dual-purpose chicken for eggs and meat, and one of my country's precious poultry breed resources. It has the following outstanding excellent traits: tolerance to roughage, strong disease resistance, and suitable for grazing in the wild; second, the meat is tender, delicious, the soup is mellow, rich in nutrition, and has a strong tonic effect; third, the hens lay more eggs, large eggs, thick egg whites, dark egg yolk color, thick egg shells, and are resistant to storage and transportation.

Anka broiler is one of the finest broiler breeds in the world today, and is also the fastest growing red and yellow-feathered broiler in China. It has the characteristics of strong adaptability, stress resistance, fast growth rate, and high feed conversion rate.

The experimental subjects used in the embodiment of the present invention are the Gushi chicken-Anka chicken _F2 generation resource group from the Yuanyang germplasm resource field of Henan Agricultural University. They are fed and watered freely under the same feeding and management environment. The cultivation method and feeding method are as follows:

Cultivation method:

The Gushi-Anka chicken resource group was established according to the _F2 distant half-sib design. A total of 7 families were established in the experiment, of which 4 orthogonal lines were Anka chickens. ×Gushi Chicken Gushi chicken ×Ankh Chicken The _F0 generation is formed by selecting breeders from the pure lines of Gushi chickens for both egg and meat and Anka chickens for meat, and mating them at a ratio of 1:6 between male and female chickens. The selected male and female chickens are required to have the characteristics of this breed, high egg production, medium weight, and pure bloodline, so as to ensure the heterozygosity of _F1 generation individuals at various loci. A rooster is selected from the _F1 offspring of each family, and mated with hens of other families at a ratio of ₁ :9 to produce F2 generation, which is required to have no genetic relationship with the mating male and female chickens. The breeding hens of _F1 generation are also scattered in various families as much as possible. When selecting, try to select individuals with rich appearance and heterozygosity to ensure that the traits of _F2 generation are greatly separated. This group includes 42 chickens of F0 _generation , 70 chickens of F1 _generation , and 860 chickens of F2 _generation . There are ₇₇₂ individuals with complete economic traits in F2 generation in the resource group.

Feeding method: The chickens were raised in the experimental chicken farm of Henan Agricultural University, and the slaughter experiment was completed in the poultry genetic improvement laboratory of Henan Agricultural University. The nutritional level of the chickens during the feeding period: the energy level of 0-4 weeks was 12.40MJ/kg, and the protein level was 20.1%; the energy level of 5-8 weeks was 12.70MJ/kg, and the protein level was 18.2%; the energy level of 9-12 weeks was 12.75MJ/kg, and the protein level was 16.0%. The chickens of different families were mixed, caged, fed freely, and had sufficient drinking water.

The present invention is further described in detail below in conjunction with specific examples. Unless otherwise specified, the equipment and reagents used in each embodiment, experimental example and comparative example can be obtained from commercial sources.

Example 1 of a chicken FGF2 gene SNP molecular marker

The nucleotide sequence of the chicken FGF2 gene SNP molecular marker in this embodiment is shown in SEQ ID NO.1, and the 174th base from the 5' end is T or C. The SNP site corresponds to the 53587229th deoxynucleotide (i.e., rs53587229 site) of the positive strand of chromosome 4 of the chicken reference genome GRCg6a version sequence information published by NCBI.

Example 1 of the application of chicken FGF2 gene SNP molecular marker in chicken growth trait and/or carcass trait and/or body size trait improvement breeding

In this embodiment, the chicken FGF2 gene SNP molecular marker is used in the breeding for improving chicken growth traits and/or carcass traits and/or body size traits. The genotype of the SNP molecular marker is detected. When the genotype of the SNP molecular marker is TT, the chicken to be tested is a high-weight, large-body individual. When the genotype of the SNP molecular marker is CC, the chicken to be tested is a low-weight, small-body individual. Individuals with the SNP molecular marker genotype TT are selected to establish a chicken population with excellent genetic resources.

Example 1 of detection primers for detecting chicken FGF2 gene SNP molecular marker genotype

The primers for detecting the SNP molecular marker genotype of the chicken FGF2 gene in this embodiment are as follows:

F Primer: 5’-CACACAGAGGACTACATCCAAATTC-3’ (shown in SEQ ID NO. 2);

R Primer: 5'-ACATACAGGGTTTCTGCATTCTCC-3' (shown in SEQ ID NO. 3).

Example 1 of the application of detection primers in chicken germplasm resource improvement

The detection primers of this embodiment are used in the improvement of chicken germplasm resources to detect the genotype of SNP molecular markers, select individuals with SNP molecular markers as TT genotype, establish a chicken population with excellent genetic resources, and improve the germplasm resources of local chickens.

Specifically, it is used in improving chicken weight, tibia length, tibia circumference, chest width, sternum length, oblique body length, half-eviscerated, fully eviscerated, head weight, claw weight, double wing weight, liver weight, gizzard weight, spleen weight, pancreas weight, breast muscle weight, leg weight, leg muscle weight, gizzard rate, leg muscle weight rate and/or weight resources after plucking.

Experimental Example 1 Extraction and Detection of Chicken Genomic DNA

In this experimental example, genomic DNA was extracted from the _F2 generation of the Gushi chicken-Anka chicken resource group. The specific operation steps are as follows:

1.1. Extraction of genomic DNA

A total of 772 chickens of the _F2 generation of Gushi chicken-Anka chicken resource group were used as materials. 5 mL of blood was drawn from the jugular vein of each chicken, anticoagulated with EDTA (10 mmol/L Tris-Cl, 0.2 mmol/L EDTA, pH 8.0), and stored at -80°C. Genomic DNA was extracted from blood samples of the _F2 generation resource group using the phenol-chloroform extraction method, dissolved in TE buffer, and stored at 4°C for later use. The specific experimental steps are as follows:

(1) Take 80 μL of whole blood and place it in a 1.5 mL centrifuge tube. Add 500 μL of TE buffer, 10 μL of proteinase K (10 mg/mL), and 12 μL of 25% SDS lysis buffer. Mix by shaking for 10 min and place in a 55°C water bath overnight.

(2) Add an equal volume of Tris-saturated phenol, shake and mix for 10 min, and centrifuge at 10,000 rpm for 10 min;

(3) Take the supernatant, add an equal volume of Tris-saturated phenol, shake and mix for 10 min, and centrifuge at 10,000 rpm for 10 min;

(4) Take the supernatant, add an equal volume of phenol/chloroform/isoamyl alcohol mixed solution (25:24:1), shake and mix, and centrifuge at 10,000 rpm for 10 min;

(5) Take the supernatant, add an equal volume of phenol/chloroform mixed solution (24:1), shake and mix, and centrifuge at 10,000 rpm for 10 min;

(6) Take the supernatant, add 2 volumes of anhydrous ethanol precooled to -20°C, shake slightly, and centrifuge at 10,000 rpm for 10 min;

(7) Discard the supernatant, add 500 μL 70% ethanol to wash the precipitate, invert and air-dry at room temperature, add an appropriate amount of TE (pH 8.0) to dissolve the DNA, store at 4°C until the DNA is completely dissolved, detect its quality by 1% agarose gel electrophoresis, and store at -80°C.

1.2. Spectrophotometric determination of genomic DNA concentration

Use a UV photometer to measure the OD value of the DNA sample at 260nm and 280nm. Calculate the DNA content and the ratio of OD260/OD280. If the OD260/OD280 ratio is less than 1.6, it means that the sample contains more protein or phenol, and purification should be performed; if the ratio is greater than 1.8, RNA purification should be considered.

DNA concentration (ng) = 50 × OD260 value × dilution multiple;

After the DNA test is completed, a certain amount is taken out and diluted to 100 ng/μL, and stored at -20°C for future use, and the rest is stored at -80°C.

Experimental Example 2 Detection of Chicken FGF2 Gene Polymorphism

In this experimental example, the polymorphism of the chicken FGF2 gene was detected, and a SNP site rs53587229 was found in the intron 1 of the chicken FGF2 gene (the genome sequence in GenBank is used as a reference (GRCg6a (GCF_000002315.6), GeneID: 396413 )). The SNP molecular marker is shown in SEQ ID NO.1, and the 174th base from the 5' end of the sequence is T or C. The SNP molecular marker was detected and analyzed to be significantly correlated with the growth traits, carcass traits and body size traits of chickens. The specific operation steps for obtaining the SNP site are as follows:

2.1. Construction of DNA pool

100 DNA samples with a concentration of 100 ng/μL in Experimental Example 1 were randomly selected, and 0.5 μL of DNA was taken from each sample to mix and construct a DNA pool.

2.2. Amplification Primer Design

The chicken FGF2 gene genome sequence in GenBank was used as a reference (GRCg6a (GCF_000002315.6), GeneID: 396413 ), and the sequencing PCR primer pair of chicken FGF2 was designed using NCBI. The total length of the amplified fragment was 597 bp. The agarose gel electrophoresis pattern of the PCR product used to detect the polymorphism is shown in Figure 1. As can be seen from the figure, the designed primer pair has good specificity and is free of primer dimers and miscellaneous bands.

The nucleotide sequences of the sequencing PCR primer pairs are:

F Primer: 5’-CACACAGAGGACTACATCCAAATTC-3’ (shown in SEQ ID NO. 2);

R Primer: 5'-ACATACAGGGTTTCTGCATTCTCC-3' (shown in SEQ ID NO. 3).

2.3. PCR cloning of chicken FGF2 DNA sequence

Using the DNA pool as a template, PCR amplification was performed using sequencing PCR primer pairs. The PCR amplification reaction system was 10 μL. The specific reaction system is shown in Table 1, and the reaction procedure is shown in Table 2.

Table 1 PCR reaction system

Table 2 Touchdown PCR reaction procedure

2.4 PCR product sequencing

After PCR amplification, 2% agarose gel was used for electrophoresis, 120V voltage for 40min, ethidium bromide (EB) staining was used for detection, and gel imaging system SYNGENE GBOX, Kodak120 (Syngene, USA) was used for imaging. Then, the PCR product was cut and recovered and purified. The gel containing the target fragment was cut from the agarose gel under ultraviolet light, placed in a 2.0mL centrifuge tube, and then the PCR product was purified using a PCR product recovery and purification kit (Omega). The specific operation was carried out according to the instructions of the kit.

The PCR purified product was sent to Qingke Biotechnology Co., Ltd. (Beijing) for sequencing. The sequencing peak graph was analyzed and the sequence was compared. The result is shown in Figure 2 (the shadow in the figure indicates the mutation site). It can be seen from the figure that there is a T>C polymorphism in the FGF2 gene, which is the single nucleotide polymorphism of the chicken FGF2 gene screened.

Experimental Example 3 Association analysis between the SNP (rs53587229) locus of the chicken FGF2 gene and growth, carcass and body size traits

Association analysis model: SPSS software was used to analyze the correlation between gene loci and growth (weight), carcass and body size traits. To ensure that the data of each trait were normally distributed, the least squares method was used to correct the data; according to the data characteristics, the multivariate linear model was used to analyze the genotype effect and the Benferroni multiple comparison method was used to compare the differences between genotypes. The results are shown in Tables 3, 4 and 5. Model I is the association analysis model between the polymorphism of the locus and growth traits and body size traits, and Model II is the association analysis model between the polymorphic locus and carcass traits, see formulas (1) and (2) for details.

Model I: y _ijklm =μ + G _i + S _j + H _k + f _l + e _ijklm (1)

Model II:

In the formula: _yijklm is the individual phenotypic value; μ is the overall mean; _Gi is the genotype fixed effect; _Sj is the sex effect; _Hk is

—Batch effect; _fl is family effect as a random effect; b is the regression coefficient of slaughter weight; _Wijklm is individual slaughter weight; W is the group average weight, and _eijklmn is the random error.

Table 3 Association analysis between the rs53587229 mutation of chicken FGF2 gene and chicken growth traits

Note: The same letters in the same category indicate no significant difference (P＞0.05), while different letters indicate significant difference (P＜0.05)

As shown in Table 3, the T>C mutation of the SNP (rs53587229) site of the FGF2 gene is significantly associated with growth traits (birth weight, 2-12 week weight), and the weight of individuals with the TT genotype is higher than that of individuals with the TC genotype and CC genotype; the weights of individuals with the three genotypes differ significantly (P < 0.05). The results show that the T allele is conducive to the increase of chicken weight, while the C allele is not conducive to the increase of chicken weight. The TT genotype in the single nucleotide polymorphism of the rs53587229 site of the chicken FGF2 gene is used as a dominant genotype in marker-assisted selection breeding for chicken weight traits to improve chicken weight.

Table 4 Association analysis between the rs53587229 mutation of chicken FGF2 gene and chicken carcass traits

Note: The same letters in the same category indicate no significant difference (P＞0.05), while different letters indicate significant difference (P＜0.05)

As shown in Table 4, the T>C mutation of the SNP (rs53587229) site of the FGF2 gene is significantly associated with different carcass traits, and almost all of them show that the carcass traits of individuals with TT genotype are higher than those of individuals with TC and CC genotypes. The carcass traits of most individuals with TT genotype and TC genotype are significantly different (P < 0.05). This shows that the T allele is beneficial to the growth of chicken carcasses. The TT genotype in the single nucleotide polymorphism of the rs53587229 site of the chicken FGF2 gene is used as a molecular genetic marker to improve the chicken carcass in marker-assisted selection breeding of chicken carcass traits.

Table 5 Association analysis between the rs53587229 mutation of chicken FGF2 gene and chicken body size traits

Note: The same letters in the same category indicate no significant difference (P＞0.05), while different letters indicate significant difference (P＜0.05)

As shown in Table 5, the T>C mutation of the SNP (rs53587229) site of the FGF2 gene is significantly associated with different body size traits, and almost all of them show that the body size traits of individuals with TT genotype and TC genotype are higher than those of individuals with CC genotype. The body size traits of individuals with TT genotype and TC genotype are not significantly different, and the body size traits of individuals with TT genotype and CC genotype are significantly different (P < 0.05). This shows that the T allele is beneficial to the growth of chicken body size. The TT genotype in the single nucleotide polymorphism of the rs53587229 site of the chicken FGF2 gene is used as a molecular genetic marker to improve the body size of chickens in marker-assisted selection breeding of chicken body size traits.

In summary, based on the above analysis, the tested chicken individuals are selected and bred to select excellent varieties. Specifically, individuals with homozygous TT at the chicken FGF2 gene SNP (rs53587229) site are selected to improve the economic performance of the chicken.

The above embodiments are preferred implementations of the present invention. However, those skilled in the art will appreciate that the implementations of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the protection scope of the present invention.

Claims (4)

1. The application of FGF2 gene SNP molecular markers in chicken growth traits and/or carcass traits and/or body size traits improvement breeding is characterized in that: the SNP locus corresponds to 53587229 th chromosome sense strand of version GRCg a of the chicken reference genome sequence information No. 4; the growth traits are birth weight, 2 weeks weight, 4 weeks weight, 6 weeks weight, 8 weeks weight, 10 weeks weight, and 12 weeks weight; the carcass traits are half-breeder weight, full breeder weight, head weight, paw weight, diptera weight, liver weight, myostomach weight, spleen weight, pancreas weight, pectoral muscle weight, leg muscle weight, myostomach rate, leg muscle weight rate and post-dehairing weight; the body size characters are 8 weeks shank length, 4 weeks shank circumference, 8 weeks shank circumference, 4 weeks chest width, 4 weeks sternum length, 8 weeks sternum length, 12 weeks sternum length, 4 weeks oblique length, 8 weeks oblique length and 12 weeks oblique length; the chicken is Gugin chicken-Anka chicken F ₂ generation resource group.

2. The use of SNP molecular markers according to claim 1 in chicken growth trait and/or carcass trait and/or body size trait improvement breeding, characterized in that: detecting the genotype of the SNP molecular marker, and when the genotype of the SNP molecular marker is TT, the chicken to be detected is a high-weight and large-size individual; when the genotype of the SNP molecular marker is CC, the chicken to be detected is a low-weight and small-size individual.

3. The use of SNP molecular markers according to claim 2 in chicken growth trait and/or carcass trait and/or body size trait improvement breeding, characterized in that: amplifying the nucleotide sequence shown as SEQ ID NO.1 by PCR; the nucleotide sequence of the PCR amplified detection primer is shown as SEQ ID NO. 2-3.

4. The use of the SNP molecular markers of claim 3 in chicken growth trait and/or carcass trait and/or body-size trait improvement breeding, characterized in that: and detecting the genotype of the SNP molecular marker by gene sequencing the PCR amplified product.