A crossbreeding method for effectively protecting local high-quality meat duck breeds
By hybridizing Liancheng White Duck with Beijing Duck and using SNP1 and SNP2 genotype screening, the problems of long breeding time and high cost in traditional breeding have been solved, and the rapid breeding of white-feathered, black-beaked, and green-legged meat ducks with good meat quality and large body size has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INSTITUTE OF ANIMAL SCIENCES OF CHINESE ACADEMY OF AGRICULTURAL SCIENCES
- Filing Date
- 2023-05-15
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies are insufficient for efficiently breeding meat ducks with good meat quality, large body size, and the target phenotypic traits (white feathers, black beak, and blue legs), and traditional breeding methods are time-consuming and costly.
By crossing Liancheng White Duck with Beijing Duck, early selection was carried out on individuals with SNP1 and SNP2 genotypes of bb and rr to obtain F3 generation individuals, achieving the breeding goal of white feathers-black beak-blue legs.
It enables early selection, saves production costs, and quickly obtains a large number of meat ducks with the target phenotypic traits, thereby improving meat quality and body shape.
Smart Images
Figure CN118947619B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of genetic breeding, specifically relating to a hybrid breeding method for effectively protecting local high-quality meat duck breeds. Background Technology
[0002] Currently, the meat duck industry is shifting from a quantity-oriented to a quality-oriented development. The market for fast-growing meat ducks is already saturated, and the demand for high-quality meat ducks with local duck lineage is increasing significantly. Among high-quality meat duck breeds, the Liancheng White Duck is highly sought after in the market due to its unique phenotypic characteristics (white feathers, black beak, and blue legs) and medicinal value. However, it is small in size, has poor production performance, and extremely high breeding costs. The Beijing Duck, with its corresponding phenotypic characteristics of white feathers, yellow beak, and yellow legs, has the advantages of fast growth and high feed conversion rate, but its meat quality still needs improvement.
[0003] In actual production, crossbreeding Beijing ducks and Liancheng white ducks produces offspring with larger body size and better meat quality. However, phenotypic segregation exists among these offspring, with different phenotypic traits: white feathers-black beak-blue legs, gray feathers-black beak-blue legs, black feathers-black beak-black legs, and white feathers-yellow beak-yellow legs. Therefore, how to breed a population with better meat quality, larger body size, and the target phenotypic trait (white feathers-black beak-blue legs) is a pressing challenge for the meat duck industry.
[0004] While traditional breeding methods have made some progress in selecting duck plumage color traits, this process is time-consuming and costly. Summary of the Invention
[0005] The purpose of this invention is to provide an effective hybrid breeding method for protecting local high-quality meat duck breeds.
[0006] This invention provides a duck breeding method, comprising the following steps:
[0007] (1) Liancheng White Duck and Beijing Duck were crossbred to obtain the F1 generation population;
[0008] (2) Free interbreeding within the F1 generation population yields the F2 generation population;
[0009] (3) Select individuals from the F2 generation whose genotype is bb based on SNP1 and rr based on SNP2 from the population.
[0010] (4) The individuals selected in step (3) are crossbred with Liancheng White Ducks to obtain F3 generation individuals.
[0011] The present invention also provides a method for duck breeding, comprising the following steps:
[0012] (1) Liancheng White Duck and Beijing Duck were crossbred to obtain the F1 generation population;
[0013] (2) Free interbreeding within the F1 generation population yields the F2 generation population;
[0014] (3) Select individuals with the white feather-yellow beak-yellow feet phenotype from the F2 generation population who have the bb genotype based on SNP1 and the rr genotype based on SNP2.
[0015] (4) The individuals selected in step (3) are crossbred with Liancheng White Ducks to obtain F3 generation individuals.
[0016] There are three genotypes at the SNP1 locus: BB, bb, and Bb; B represents a G base and b represents an A base.
[0017] There are three genotypes at the SNP2 locus: RR, rr, and Rr; R represents a G base and r represents an A base.
[0018] The SNP1 site corresponds to position 5038595 of Chr13 in the Beijing duck reference genome and is an A>G polymorphism.
[0019] The SNP2 site corresponds to chromosome 12123297 bp on chromosome Scaffold7 of the Liancheng White Duck reference genome, and is a G>A polymorphism.
[0020] The SNP1 is either (a1) or (a2) as follows:
[0021] (a1) Nucleotide 151 in a specific DNA segment in the duck genome;
[0022] (a2) The 151st nucleotide in the target sequence of primer pair A in the duck genome;
[0023] The specific DNA segment described in (a1) is as follows: (b1) or (b2) or (b3):
[0024] (b1) As shown in SEQ ID NO: 1;
[0025] (b2) is derived from ducks and has more than 98% similarity to (b1);
[0026] (b3) is derived from duck and has fewer than 6 different nucleotides from (b1);
[0027] The SNP2 is either (c1) or (c2) as follows:
[0028] (c1) Nucleotide 171 in a specific DNA segment in the duck genome;
[0029] (c2) Nucleotide 171 in the target sequence of primer pair B in the duck genome;
[0030] The specific DNA segment described in (c1) is as follows (d1) or (d2) or (d3):
[0031] (d1) As shown in SEQ ID NO: 2;
[0032] (d2) is derived from ducks and has more than 98% identity with (d1);
[0033] (d3) is derived from duck and has fewer than 6 different nucleotides from (d1).
[0034] The primer pair A consists of primer F1 and primer R1;
[0035] The primer F1 is either (e1) or (e2) as follows:
[0036] (e1) The single-stranded DNA molecule shown in SEQ ID NO: 3;
[0037] (e2) A DNA molecule that has undergone substitution and / or deletion and / or addition of one or more nucleotides of (e1) and has the same function as (e1);
[0038] The primer R1 is either (e3) or (e4) as follows:
[0039] (e3) The single-stranded DNA molecule shown in SEQ ID NO: 4;
[0040] (e4) A DNA molecule that has undergone substitution and / or deletion and / or addition of one or more nucleotides of (e3) and has the same function as (e3).
[0041] The primer pair B consists of primer F2 and primer R2;
[0042] The primer F2 is either (f1) or (f2) as follows:
[0043] (f1) The single-stranded DNA molecule shown in SEQ ID NO: 5;
[0044] (f2) A DNA molecule that has undergone substitution and / or deletion and / or addition of one or more nucleotides of (f1) and has the same function as (f1);
[0045] The primer R2 is either (f3) or (f4) as follows:
[0046] (f3) The single-stranded DNA molecule shown in SEQ ID NO: 6;
[0047] (f4) A DNA molecule that has undergone substitution and / or deletion and / or addition of one or more nucleotides of (f3) and has the same function as (f3).
[0048] The SNP1-based genotype detection method includes the following steps: using genomic DNA as a template, performing PCR amplification with primer pair A, and then recovering the PCR amplification product and sequencing it.
[0049] The SNP2-based genotype detection method includes the following steps: using genomic DNA as a template, performing PCR amplification with primer pair B, and then recovering the PCR amplification product and sequencing it.
[0050] The F3 generation individuals are the breeding target individuals.
[0051] The purpose of the breeding is to obtain a duck with white feathers, a black beak, and blue feet.
[0052] The purpose of the breeding is to obtain ducks with white feathers, black beaks, blue feet, and increased body weight.
[0053] The meaning of "white feathers, black beak, and blue feet" is: white feathers, black beak, and blue feet.
[0054] The weight gain mentioned refers to a weight exceeding that of the Liancheng White Duck.
[0055] On the one hand, this invention enables early selection, saving production costs and accelerating genetic progress. On the other hand, the F3 generation individuals obtained by this invention all possess the target phenotypic trait, and thus, this invention can obtain a large number of individuals with the target phenotypic trait.
[0056] The beneficial effects of this invention are as follows: The two SNP molecular markers provided by this invention are associated with the Liancheng White Duck and the white-feathered, black-beaked, and blue-legged phenotypic traits. These are novel molecular markers. By determining the genotype of the duck to be tested based on the two SNP loci, early selection of the white-feathered, black-beaked, and blue-legged phenotypic traits can be achieved. This can save production costs, improve the packaging traits of meat ducks, accelerate genetic progress, and better serve duck breeding. It has great economic application value and scientific research value. Attached Figure Description
[0057] Figure 1 This is a graph showing the results of the SNP1 genome-wide association analysis.
[0058] Figure 2 This is a graph showing the results of the SNP2 genome-wide association analysis.
[0059] Figure 3 A schematic diagram of the process for preparing commercial ducks with a heterozygous genotype and the phenotypic traits of white feathers, black beak, and blue feet. Detailed Implementation
[0060] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.
[0061] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available. Unless otherwise specified, the quantitative experiments in the following embodiments are all performed in triplicate, and the results are averaged.
[0062] The physical phenotypic characteristics of the Peking duck are: white feathers, yellow beak, and yellow feet (meaning white feathers, yellow beak, and yellow feet).
[0063] The Liancheng White Duck's physical characteristics are: white feathers, black beak, and blue feet (meaning it has white feathers, a black beak, and blue feet).
[0064] Example 1: Discovery of SNPs and their correlation with traits
[0065] The inventors discovered several SNPs through genome-wide association analysis (GWAS), and then conducted association analysis on multiple traits in multiple samples, ultimately obtaining two SNPs that were correlated with the target trait.
[0066] The target trait refers to: white feathers, black beak, and blue feet (meaning white feathers, black beak, and blue feet).
[0067] Figure 1 This is a graph showing the results of the SNP1 genome-wide association analysis.
[0068] Figure 2 This is a graph showing the results of the SNP2 genome-wide association analysis.
[0069] SNP1, corresponding to position 5038595 of Chr13 in the Beijing duck reference genome, is an A>G polymorphism (this SNP and its surrounding nucleotides are shown in SEQ ID NO: 1, where R represents A or G). There are three genotypes for SNP1: BB, bb, and Bb. B represents a G base, and b represents an A base. SNP1 is associated with melanin synthesis; individuals with the bb genotype cannot form melanin, while individuals with the BB and Bb genotypes can. The ability to form melanin is a prerequisite for colored feathers, beaks, and feet (colored refers to gray, cyan, or black).
[0070] SNP2, located at 12123297 bp on chromosome Scaffold7 of the Liancheng White Duck reference genome, is a G>A polymorphism (this SNP and its surrounding nucleotides are shown in SEQ ID NO: 2, where R represents A or G). There are three genotypes for SNP2: RR, rr, and Rr. R represents a G base, and r represents an A base. SNP2 is associated with melanin transport and is specifically linked to feather color. Given that SNP1 has the bb genotype, the relationship between SNP2 genotype and feather color is as follows: individuals with the RR, rr, and Rr genotypes all have white feathers (white feather trait). Given that SNP1 has the BB or Bb genotype, the relationship between SNP2 genotype and feather color is as follows: individuals with the rr genotype have white feathers (white feather trait), individuals with the Rr genotype have gray feathers (gray feather trait), and individuals with the RR genotype have black feathers (black feather trait).
[0071] The genotype of the Beijing duck based on SNP1 is bb, and the genotype based on SNP2 is RR (multiple individuals were sampled, and the genotypes of the two SNP loci were the same).
[0072] The Liancheng White Duck has the BB genotype based on SNP1 and the rr genotype based on SNP2 (multiple individuals were sampled, and the genotypes at both SNP loci were the same).
[0073] Example 2: Design of primer pairs for SNP identification
[0074] Based on sequence analysis and preliminary experimental verification, the two primer pairs with the best performance were obtained: primer pair A (composed of primer F1 and primer R1) and primer pair B (composed of primer F2 and primer R2).
[0075] In the duck genomic DNA, the target sequence of primer pair A is 332 bp. Primer pair A's target sequence contains SNP1.
[0076] F1 (SEQ ID NO: 3): 5'-CCTGCTAGACCTGCACAACA-3';
[0077] R1 (SEQ ID NO: 4): 5'-TCTCACCTGTGGAAACTGCC-3'.
[0078] In the duck genomic DNA, the target sequence of primer pair B is 337 bp. The target sequence of primer pair B contains SNP2.
[0079] F2 (SEQ ID NO: 5): 5'-AAGGAAAAGCTCAGCCCCTG-3';
[0080] R2 (SEQ ID NO: 6): 5'-ATGCCTTTACAGCAGGAGGAG-3'.
[0081] Example 3: Preparation of commercial ducks with a heterozygous genotype and the phenotypic traits of white feathers, black beak, and blue legs.
[0082] See flowchart Figure 3 .
[0083] I. Obtaining experimental animals
[0084] 1. Liancheng White Duck and Beijing Duck were crossbred to obtain an F1 generation of 150 ducks.
[0085] The phenotypic characteristics of individuals in the F1 generation were: gray feathers, black beak, and blue legs.
[0086] 2. The F1 generation group mates freely within the group to obtain the F2 generation group (composed of 480 individuals).
[0087] Based on phenotypic traits, the F2 generation was divided into four subgroups as follows: 88 individuals with white feathers, black beaks, and blue legs; 182 individuals with gray feathers, black beaks, and blue legs; 91 individuals with black feathers, black beaks, and black legs; and 119 individuals with white feathers, yellow beaks, and yellow legs.
[0088] II. Detection of genotypes based on specific SNP loci
[0089] Genotyping was performed on the experimental animals (i.e., 119 white-feathered, yellow-beaked, yellow-legged individuals from the F2 generation obtained in step one).
[0090] 1. Blood sample collection
[0091] Blood from the wing veins of experimental animals was collected using heparin sodium anticoagulant blood collection tubes and stored at -20°C for later use.
[0092] 2. Extract genomic DNA
[0093] Take the venous blood obtained in step 1 and extract genomic DNA.
[0094] 3. Genotyping
[0095] Using the genomic DNA obtained in step 2 as a template, PCR amplification was performed using primer pair A and primer pair B, respectively. The PCR amplification products were then recovered and sequenced.
[0096] Thirty individuals were identified as having the bb genotype based on SNP1 and the RR genotype based on SNP2.
[0097] Thirty individuals were identified as having the bb genotype based on SNP1 and the rr genotype based on SNP2.
[0098] 59 individuals were identified as having the bb genotype based on SNP1 and the Rr genotype based on SNP2.
[0099] III. Obtaining the duck product
[0100] Individuals selected in step two with the genotype bb based on SNP1 and the genotype rr based on SNP2 were crossed with Liancheng White Ducks to obtain an F3 generation population of 304 individuals.
[0101] All individuals in the F3 generation were used as experimental animals, and their genotypes were determined according to the method in step two. These individuals all had the following genotypes: Bb based on SNP1 and rr based on SNP2.
[0102] All individuals in the F3 generation exhibit the phenotype of "white feathers, black beak, and blue feet".
[0103] IV. Weight trait testing
[0104] The body weight traits of F3 generation individuals obtained in step three, as well as those of Beijing ducks and Liancheng white ducks of the same period, were tested. The results are shown in Table 1. Random sampling was used, with 60 individuals sampled from each test group.
[0105] Table 1 (Data format: mean ± standard deviation; unit: g; n represents quantity)
[0106] Varieties / Strains 6 weeks old 8 weeks old 10 weeks old Liancheng White Duck 1834.2±27.2(n＝60) 2002.5±25.5(n＝60) 2102±24.4(n＝60) F3 generation individuals 2660±20.9(n＝60) 2935.1±25.8(n＝60) 3107±29.6(n＝60) Beijing Duck 2691±25.1(n＝60) 2978.7±23.0(n＝60) 3160±32.1(n＝60)
[0107] Note: In each testing group, there were half males and half females.
[0108] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some of the essential features can be applied within the scope of the following appended claims.
Claims
1. A method for breeding ducks, comprising the following steps: (1) Liancheng White Duck and Beijing Duck were crossbred to obtain the F1 generation population; (2) The F1 generation population mates freely within the population to obtain the F2 generation population; (3) Select individuals from the F2 generation whose genotype is bb based on SNP1 and rr based on SNP2 from the population; (4) Crossbreed the individuals selected in step (3) with Liancheng White Ducks to obtain F3 generation individuals; There are three genotypes at the SNP1 locus: BB, bb, and Bb; B represents a G base and b represents an A base. There are three genotypes at the SNP2 locus: RR, rr, and Rr; R represents a G base and r represents an A base. The SNP1 is either (a1) or (a2): (a1) Nucleotide 151 in the specific DNA segment shown in SEQ ID NO: 1 in the duck genome; (a2) Nucleotide 151 in the target sequence of primer pair A in the duck genome; The SNP2 is either (c1) or (c2) as follows: (c1) Nucleotide 171 in the specific DNA segment shown in SEQ ID NO: 2 in the duck genome; (c2) Nucleotide 171 in the target sequence of primer pair B in the duck genome; The primer pair A consists of primer F1 and primer R1; primer F1 is the single-stranded DNA molecule shown in SEQ ID NO: 3; primer R1 is the single-stranded DNA molecule shown in SEQ ID NO: 4; Primer pair B consists of primer F2 and primer R2; primer F2 is the single-stranded DNA molecule shown in SEQ ID NO: 5; primer R2 is the single-stranded DNA molecule shown in SEQ ID NO: 6; The F3 generation individuals are the breeding target individuals; the purpose of the breeding is to obtain ducks with white feathers, black beaks, and blue feet, and with increased weight; the increased weight refers to a weight higher than that of Liancheng White Duck.
2. A method for breeding ducks, comprising the following steps: (1) Liancheng White Duck and Beijing Duck were crossbred to obtain the F1 generation population; (2) The F1 generation population mates freely within the population to obtain the F2 generation population; (3) Select individuals from the F2 generation population with the white feather-yellow beak-yellow feet phenotype who have the genotype bb based on SNP1 and the genotype rr based on SNP2; (4) Crossbreed the individuals selected in step (3) with Liancheng White Ducks to obtain F3 generation individuals; There are three genotypes at the SNP1 locus: BB, bb, and Bb; B represents a G base and b represents an A base. There are three genotypes at the SNP2 locus: RR, rr, and Rr; R represents a G base and r represents an A base. The SNP1 is the SNP1 described in claim 1; The SNP2 is the SNP2 described in claim 1; The F3 generation individuals are the breeding target individuals; the purpose of the breeding is to obtain ducks with white feathers, black beaks, and blue feet, and with increased weight; the increased weight refers to a weight higher than that of Liancheng White Duck.