Application of SNP molecular marker related to feed conversion rate in Tianhua mutton sheep breeding

Abstract

The application discloses application of a SNP molecular marker related to feed conversion rate of Tianhua mutton sheep in breeding of the Tianhua mutton sheep and belongs to the technical field of molecular biology and genetic breeding. The SNP molecular marker related to the feed conversion rate of the Tianhua mutton sheep is located at 57088706 bp of chromosome 15 of a sheep reference genome ARS-UI_Ramb_v2.0, and a base mutation is C>T (rs399570735). Whole genome resequencing and feed conversion rate determination data show that the SNP marker has a significant influence on the feed conversion rate of the Tianhua mutton sheep. Therefore, the rs399570735 can be applied to molecular marker selection breeding of the feed conversion rate trait of the Tianhua mutton sheep, and the breeding process of a high-efficiency type strain of the Tianhua mutton sheep can be accelerated.

Description

Technical Field

[0001] This invention belongs to the field of molecular biology and genetic breeding technology, specifically involving the application of SNP molecular markers related to the feed conversion rate of Tianhua meat sheep in the breeding of Tianhua meat sheep. Background Technology

[0002] Tianhua meat sheep is a new breed of fine-wool meat sheep adapted to the cold and arid natural environment of high altitudes, suitable for grazing, semi-grazing and semi-stall feeding, and stall feeding. Through four generations of continuous selective breeding, Tianhua meat sheep is sire-born from South African meat Merino sheep (62.5% bloodline) and dam-born from Gansu alpine fine-wool sheep (37.5% bloodline). It is characterized by its large size, rapid growth and development, and high reproductive capacity. Furthermore, Tianhua meat sheep combines the dual-purpose characteristics of South African meat Merino sheep (meat and wool) with the adaptability to cold regions and wool performance of Gansu alpine fine-wool sheep.

[0003] Feed costs constitute a significant portion of total livestock production costs and are a key factor determining the economic benefits of livestock farming. Feed conversion ratio (FCR) refers to the amount of feed required for a unit of body weight gain, directly reflecting the efficiency of feed utilization by animals. Lowering FCR can correspondingly reduce feed consumption per unit of body weight gain, thereby saving on livestock costs. However, FCR is a complex trait that is difficult to measure directly, and its accurate determination relies on long-term, systematic individual feeding records, including data on feed intake, uneaten feed, and periodic weight changes. Traditional phenotypic record-based selection methods for improving FCR not only have long measurement cycles but also suffer from high breeding costs and slow genetic progress due to significant interference from environmental factors. Molecular marker-assisted selection (MMR) technology provides a new approach for the genetic improvement of FCR. Compared to traditional phenotypic selection methods, MMR can accelerate the breeding process and improve breeding efficiency.

[0004] Single nucleotide polymorphisms (SNPs) are a class of molecular genetic markers proposed in 1996 by Lander, a researcher at the Human Genome Research Center at MIT. They primarily refer to DNA sequence polymorphisms caused by variations in a single nucleotide at the genomic level. SNPs exhibit polymorphisms involving only a single base, manifesting as transitions, transversions, insertions, and deletions. SNPs are the most common type of variation in the genome. Genome-wide association studies (GWAS) are molecular marker screening methods based on whole-genome resequencing, linking traits to variant sites. This is considered an ideal method for identifying variant sites associated with complex traits. Currently, no SNP sites associated with the feed conversion ratio of Tianhua mutton sheep have been reported. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide the application of SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep in the breeding of Tianhua mutton sheep.

[0006] To achieve the above objectives, the present invention employs the following technical solution: The first aspect of this invention discloses the application of SNP molecular markers related to feed conversion rate in Tianhua mutton sheep breeding. The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.1. The 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is the SNP site. The SNP site is located at nucleotide 57088706 on chromosome 15 of the sheep reference genome ARS-UI_Ramb_v2.0. The SNP site is C or T.

[0007] Preferably, the feed conversion rate of Tianhua mutton sheep individuals with the CC genotype of the SNP molecular marker associated with the feed conversion rate is significantly lower than that of Tianhua mutton sheep individuals with the CT genotype.

[0008] In a second aspect, the present invention discloses the application of SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep in the preparation of products for predicting the feed conversion rate trait of Tianhua mutton sheep. The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.1. The 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is the SNP site. The SNP site is located at nucleotide 57088706 on chromosome 15 of the sheep reference genome ARS-UI_Ramb_v2.0. The SNP site is C or T.

[0009] Preferably, the feed conversion rate of Tianhua mutton sheep individuals with the CC genotype of the SNP molecular marker associated with the feed conversion rate is significantly lower than that of Tianhua mutton sheep individuals with the CT genotype.

[0010] Preferably, the product is a primer pair for amplifying SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep, or a kit containing the primer pair.

[0011] A third aspect of the present invention discloses a method for detecting the feed conversion ratio trait of Tianhua mutton sheep. The method predicts the feed conversion ratio trait of Tianhua mutton sheep by detecting SNP molecular markers related to the feed conversion ratio of Tianhua mutton sheep. The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.1, and the 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is C or T.

[0012] Preferably, the genomic DNA of the Tianhua mutton sheep to be tested is extracted and amplified by PCR. The PCR amplification product is then sequenced. Based on the sequencing results, the genotype of the SNP marker of the Tianhua mutton sheep to be tested is determined, and the feed conversion ratio trait of the Tianhua mutton sheep is predicted.

[0013] Preferably, the feed conversion ratio of Tianhua mutton sheep individuals with the CC genotype at the SNP molecular marker site is significantly lower than that of Tianhua mutton sheep individuals with the CT genotype.

[0014] In a fourth aspect, the present invention discloses a method for screening Tianhua meat sheep with feed efficiency traits, which involves detecting SNP molecular markers related to feed conversion rate in Tianhua meat sheep, selecting Tianhua meat sheep individuals with genotype CC as breeding sheep for feed efficiency Tianhua meat sheep strains, and culling Tianhua meat sheep individuals with genotype CT. The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.1, and the 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is C or T.

[0015] A fifth aspect of the present invention discloses a primer set for detecting SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep, the primer set comprising an upstream primer and a downstream primer, the nucleotide sequences of which are shown in SEQ ID NO.2 and SEQ ID NO.3, respectively.

[0016] A sixth aspect of the present invention discloses a kit containing the primer set described above for detecting SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides the application of SNP molecular markers related to feed conversion ratio in the breeding of Tianhua mutton sheep. Based on the whole-genome resequencing of Tianhua mutton sheep, the SNP molecular marker rs399570735, which is significantly associated with feed conversion ratio, was screened. Different genotypes of this SNP showed significant differences in feed conversion ratio. The average feed conversion ratio of the CC genotype was 7.642, while the average feed conversion ratio of the CT genotype was 8.508. The feed conversion ratio of the CC genotype in Tianhua mutton sheep was significantly lower than that of the CT genotype. P The value <0.05 indicates that homozygous CC Tianhua sheep individuals have significantly higher feed utilization efficiency than CT heterozygous individuals. Therefore, applying the SNP (rs399570735) molecular marker to breeding practice and selecting CC-type Tianhua sheep individuals as breeding stock for feed-efficient strains will accelerate the breeding process of feed-efficient Tianhua sheep strains, provide a basis and materials for marker-assisted selection of feed conversion efficiency, and ultimately improve economic benefits. Attached Figure Description

[0018] Figure 1 Manhattan plot of genome-wide SNP effect distribution of Tianhua sheep feed conversion rate in Example 1 of this invention; Figure 2 This is a scatter plot of feed conversion rate for Tianhua meat sheep of each SNP genotype in Example 2 of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to understand the features and effects of the present invention, the following description and definitions are only general descriptions of the terms and expressions mentioned in the specification. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0021] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0022] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0023] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0024] This invention provides a SNP marker associated with the feed conversion ratio of Tianhua mutton sheep. The nucleotide sequence is shown in SEQ ID NO.1 in Table 1. The polymorphic site of the SNP marker associated with the feed conversion ratio of Tianhua mutton sheep is located at position 151 from the 5' end of the sequence shown in SEQ ID NO.1, and the polymorphism is C / T. That is, the SNP marker associated with the feed conversion ratio of Tianhua mutton sheep is located at position 57088706 bp on chromosome 15 of the sheep reference genome ARS-UI_Ramb_v2.0. BDNFThe molecular marker rs399570735 (ARS-UI_Ramb_v2.0 / Chr15: 57088706 / "C":rs399570735) is located 50,148 bp upstream of the gene. This SNP molecular marker is significantly associated with the feed conversion ratio of Tianhua mutton sheep and can be used for early prediction of feed conversion ratio and marker-assisted selection breeding of Tianhua mutton sheep.

[0025] Table 1 Sequence List

[0026] This invention also provides a method for breeding a high-efficiency feed-type Tianhua mutton sheep breed. The method involves detecting the aforementioned SNPs in the Tianhua mutton sheep genome, selecting individuals with the CC genotype as breeding sheep for the high-efficiency feed-type Tianhua mutton sheep breed, and culling individuals with the CT genotype.

[0027] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0028] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated.

[0029] In the following embodiments, the method for SNP marker detection in the Tianhua mutton sheep to be tested is not particularly limited. Sequencing, single-strand conformation polymorphism polymerase chain reaction (PCR-SSCP), restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP), and time-of-flight mass spectrometry are all techniques that can be used to detect SNPs. Among these, sequencing is the most accurate, flexible, high-throughput, and short-cycle detection technique. Only a pair of primers needs to be designed upstream and downstream of the SNP site to amplify the product, and then sequencing can directly detect the genotype of the SNP site. Therefore, this invention uses sequencing for SNP marker detection. According to some specific examples of this invention, by detecting the aforementioned SNP markers in the Tianhua mutton sheep to be tested, feed-efficient Tianhua mutton sheep can be screened.

[0030] In the following embodiments, the method for sequencing the PCR amplification products is not particularly limited, as long as the PCR amplification products, i.e., the sequences of the fragments containing the SNP markers related to the feed conversion rate of Tianhua mutton sheep, can be obtained effectively. According to some specific examples of the present invention, at least one method selected from HISEQ2000, SOLiD, 454, and single-molecule sequencing can be used to sequence the PCR amplification products. This allows for high-throughput, rapid, efficient, and accurate sequencing results.

[0031] Example 1: Obtaining SNP markers associated with feed conversion ratio of Tianhua mutton sheep 1. A total of 168 Tianhua sheep aged 6-11 months were selected from two large-scale breeding farms as the experimental group, including 100 rams and 68 ewes.

[0032] Average daily feed intake: Feed and water are withheld at 9 pm the night before the sheep are weighed each month. The remaining feed in the trough is removed and weighed. The total amount of feed added in the month is subtracted from the amount of remaining feed to get the feed intake for the month. Then, the feed intake for the month is divided by the number of days in the month to get the average daily feed intake for the month.

[0033] Average daily weight gain: Sheep are fasted and deprived of water at 9 pm the night before each weighing, and weighed on an empty stomach at 9 am the next morning. The weight gain for the current month is calculated by subtracting the previous month's weight from the current month's weight, and then divided by the number of days in the current month to obtain the average daily weight gain for the current month.

[0034] Feed conversion ratio = average daily feed intake / average daily weight gain.

[0035] Table 2. Descriptive statistics of feed conversion rate for Tianhua mutton sheep.

[0036] 2. Whole blood (4-5 mL) was collected from 168 Tianhua sheep individuals using the jugular vein sampling method in EDTA anticoagulant blood collection tubes. The blood was transported at low temperature and stored in the laboratory at -20°C. GenoBaits was used. ® The DNA Library Prep Kit for ILM is used to construct a resequencing library from quality-tested DNA. Take 200 ng of quantified, quality-tested DNA and place it in a 0.2 mL PCR tube. Add 4 μL of GenoBaits to the tube. ® End Repair Buffer and 2.6 μL GenoBaits ® Add EndRepair Enzyme, bring water to 20 μL, and incubate in an ABI 9700 PCR instrument at 37°C for 20 min, followed by denaturation at 72°C for 20 min to complete DNA fragmentation, end repair, and A-tailing. Add 2 μL of GenoBaits. ®Ultra DNA Ligase, 8 μL GenoBaits ® Add 4 μL of Ultra DNA Ligase Buffer and 4 μL of GenoBaits® Adapter for ILM, then add water to a final volume of 40 μL. Incubate on an ABI 9700 PCR instrument at 22°C for 60 min to complete the ligation of the sequencing adapter. Next, add 48 μL of GenoPrep DNA Clean Beads to the ligation product to purify it. After purification, use 0.68 + 0.2 magnetic beads to screen for fragments, retaining ligation products with insert fragments between 300 and 350 bp. Add 10 μL of sequencing adapter with barcode sequence and 10 μL of GenoBaits to the PCR tube from the previous step. ® Prepare PCR Master Mix and add water to a final volume of 20 μL. Amplification was performed using an ABI 9700 PCR instrument with the following program: 98℃ pre-denaturation for 2 min, 98℃ denaturation for 30 s, 65℃ annealing for 30 s, 72℃ extension for 40 s, 5 cycles, followed by a final extension at 72℃ for 4 min. Add 20 μL of GenoPrep DNA Clean Beads to the second round PCR product, place on a magnetic rack until the solution is clear, discard the supernatant, add 100 μL of 80% ethanol to wash the magnetic beads, and add 35 μL of 10 mM Tris-HCl to obtain the purified DNA library. After library construction, preliminary quantification was performed using Qubit 2.0, and qPCR was used to accurately quantify the effective concentration of the library to ensure library quality. After passing quality testing, sequencing was performed using the BGI MGI-2000 / MGI-T7 sequencing platform in PE150 mode.

[0037] 3. Use the software FastP (version 0.20.0) to filter raw reads to obtain clean reads: If the number of N bases in a sequencing read exceeds 10, or if the number of low-quality (Q ≤ 20) bases in a sequencing read exceeds 40% of the read length, remove the paired reads. Use BWA-MEM (0.7.13-r1126) to align the filtered, high-quality sequences to the NCBI Sheep Reference Genome ARS-Ul Ramb v2.0 (GCF 016772045.1). Then, use Picard v2.18.2 (http: / / broadinstitute.github.io / picard / ) to sort the aligned BAM files and remove duplicate sequences. Use Qualimap (v2.2) to calculate the alignment rate and average depth for all samples. Finally, the HaplotypeCaller, CombineGVCFs, GenotypeGVCFs, and VariantFiltratio tools from the Genome Analysis Toolkit (GATK, version 3.6-0-g89b7209) were used to obtain SNP loci (the CombineGVCFs module was used to merge multiple GVCF files into one large GVCF file, and the GenotypeGVCFs module was used to process the merged GVCF file), outputting the final VCF file. PLINK software was used to remove SNPs with a deletion rate >2% and a minimum allele frequency <5% from 168 samples, as well as SNPs located on sex chromosomes, resulting in a VCF file containing 26,784,685 SNPs and a size of 20.76 Gb. The principal component file of this VCF was then generated using PLINK software.

[0038] 4. Genome-wide association analysis was performed on the feed conversion ratio (FCR) of Tianhua mutton sheep using a mixed linear model (MLM) in GEMMA software (v0.98.5): y = Xβ + Zu + ε in, y It is an n×1 vector of phenotypic values ​​(n is the number of individuals), i.e., the vector of FCR observation values; X Design a matrix for n×p fixed effects ( p (Number of fixed-effect parameters), including intercept, SNP marker genotype, and covariates (number of sessions, age in months, sex, and the first three principal components); βThis is a p×1 fixed effects coefficient vector containing estimates of the SNP effects to be tested; Z Design a matrix for an n×n random effect, where the matrix is ​​the identity matrix. I ; u Let n×1 be a random multigene effect vector, following a multivariate normal distribution. u ~ N (0, K σ g 2 ),in K Let σ be an n×n kinship matrix. g 2 The variance is multigene variance; ε is an n×1 residual vector, following a multivariate normal distribution ε~N(0, I σ e 2 ),in I σ is the identity matrix. e 2 This represents the residual variance.

[0039] 5. Use -log 10 P = 6 was used as a significant threshold at the genome level to screen for significant associated sites. The significant SNPs were aligned to the sheep reference genome (ARS-Ul Ramb v2.0) using bedtools software for gene annotation.

[0040] 6. Chromosome 15 of Tianhua meat sheep was identified through GWAS screening. BDNF A single SNP marker (rs399570735) located 50,148 bp upstream of the gene is significantly associated with feed conversion ratio. Figure 1 The SNP sites in the test samples contained both C and T base types, that is, the nucleotide sequence shown in Table 1, SEQ ID NO.1, showed a C / T polymorphism at position 151 from the 5' end. Detailed information is as follows (Table 3): Table 3 SNP Information

[0041] Example 2: Detection of the effect of SNP markers The genotyping results of SNP (rs399570735) in 168 individuals were extracted using VCFtools software. The Mann-Whitney U test (two-tailed) was performed on the feed conversion rate of different genotypes of this SNP using the scipy.stats module in Python (Table 4).

[0042] Table 4. Association between SNP and feed conversion ratio

[0043] The above results indicate that SNP (rs399570735) significantly affected the feed conversion ratio of Tianhua mutton sheep, with the CC type showing a significantly lower feed conversion ratio than the CT type. P <0.05)( Figure 2 The lower the feed conversion ratio, the higher the feed utilization efficiency. This indicates that homozygous CC individuals have significantly higher feed utilization efficiency than CT heterozygous individuals. In breeding practice, CC-type Tianhua meat sheep individuals can be selected as high-efficiency feed breeds.

[0044] Example 3: Cultivating Tianhua meat sheep with feed efficiency traits using SNP markers associated with feed conversion ratio. First, genomic DNA was extracted from Tianhua sheep. Then, using the upstream and downstream sequences of chromosome 15 at position 57088706 bp in the sheep reference genome ARS-UI_Ramb_v2.0 (as shown in SEQ ID NO.1 in Table 1) as templates, PCR amplification primers were designed using Primer 5.0 software. The nucleotide sequences of the upstream and downstream primers are shown in SEQ ID NO.2 and SEQ ID NO.3 in Table 1, respectively. Using the extracted Tianhua sheep genomic DNA as a template, PCR amplification was performed using the above primers. After PCR amplification, agarose gel electrophoresis was performed to confirm that the amplified fragment size was consistent with the expected size. After confirming the target fragment, the amplified product was recovered and purified using a PCR recovery kit, following the kit's instructions. Finally, the purified PCR amplification products were sequenced using HISEQ2000, SOLiD, 454 or single-molecule sequencing methods. Based on the sequencing results, the genotype of the SNP (rs399570735) molecular marker of the Tianhua mutton sheep to be tested was determined. Tianhua mutton sheep individuals with the CC genotype were selected as breeding sheep for the feed-efficient Tianhua mutton sheep breed, while individuals with the CT genotype were eliminated, thus achieving the selective breeding of Tianhua mutton sheep in terms of feed conversion rate.

[0045] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. The application of SNP molecular markers related to feed conversion rate in Tianhua meat sheep breeding, characterized in that, The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.

1. The 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is the SNP site. The SNP site is located at nucleotide 57088706 on chromosome 15 of the sheep reference genome ARS-UI_Ramb_v2.

0. The SNP site is C or T.

2. The application of the SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep as described in claim 1 in the breeding of Tianhua mutton sheep, characterized in that, The feed conversion rate of Tianhua mutton sheep individuals with the CC genotype of the SNP molecular markers associated with feed conversion rate was significantly lower than that of Tianhua mutton sheep individuals with the CT genotype.

3. The application of SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep in the preparation of products for predicting the feed conversion rate trait of Tianhua mutton sheep, characterized in that, The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.

1. The 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is the SNP site. The SNP site is located at nucleotide 57088706 on chromosome 15 of the sheep reference genome ARS-UI_Ramb_v2.

0. The SNP site is C or T.

4. The application of the SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep as described in claim 3 in the preparation of products for predicting the feed conversion rate trait of Tianhua mutton sheep, characterized in that, The feed conversion rate of Tianhua mutton sheep individuals with the CC genotype of the SNP molecular markers associated with feed conversion rate was significantly lower than that of Tianhua mutton sheep individuals with the CT genotype.

5. The application of the SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep as described in claim 3 in the preparation of products for predicting the feed conversion rate trait of Tianhua mutton sheep, characterized in that, The product is a primer pair for amplifying SNP molecular markers related to the feed conversion rate of Tianhua mutton sheep, or a kit containing the primer pair.

6. A method for detecting the feed conversion ratio of Tianhua mutton sheep, characterized in that, By detecting SNP molecular markers related to feed conversion rate of Tianhua mutton sheep, the feed conversion rate trait of Tianhua mutton sheep can be predicted. The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.1, and the 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is C or T.

7. The method for detecting the feed conversion ratio of Tianhua mutton sheep according to claim 6, characterized in that, By extracting genomic DNA from the Tianhua mutton sheep to be tested and performing PCR amplification, sequencing the PCR amplification products, determining the genotype of the SNP marker in the Tianhua mutton sheep to be tested based on the sequencing results, and predicting the feed conversion ratio trait of Tianhua mutton sheep.

8. A method for screening Tianhua meat sheep with high feed efficiency traits, characterized in that, SNP molecular markers related to feed conversion ratio in Tianhua mutton sheep were detected. Tianhua mutton sheep individuals with genotype CC were selected as breeding sheep for the feed-efficient Tianhua mutton sheep breed, while Tianhua mutton sheep individuals with genotype CT were culled. The nucleotide sequence of the SNP molecular marker is shown in SEQ ID NO.1, and the 151st base from the 5' end of the sequence shown in SEQ ID NO.1 is C or T.

9. A primer set for detecting SNP molecular markers related to feed conversion ratio in Tianhua mutton sheep, characterized in that, The primer set includes an upstream primer and a downstream primer, the nucleotide sequences of which are shown in SEQ ID NO.2 and SEQ ID NO.3, respectively.

10. A kit containing the primer set of claim 9 for detecting SNP molecular markers associated with Tianhua sheep feed conversion ratio.

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