Positional Cloning

Positional Cloning

Lifeasible, as a leading company in plant breeding technologies, offers tailored positional cloning service for our customers worldwide.

What Is Positional Cloning?

What Is Positional Cloning?

Positional cloning, also known as map-based cloning, is a technique for the positioning of a trait-associated gene in the genome and involves methods such as linkage analysis, association mapping, and bioinformatics. Due to its high efficiency and accuracy, the positional cloning technique has shed light on modern plant breeding for the identification of genes or quantitative trait loci (QTLs) associated desired traits, and can potentially accelerate marker-assisted selection as well as introduction of valuable traits.

The principle of positional cloning is to isolate a particular allele from a cDNA library with specific primers, using chromosome waking or thermal asymmetric interlaced PCR (tail-PCR), which are used in the identification of unknown regions flanking a known DNA sequence.

What We Offer

Initial Positioning Isolating populations: F2, BC1, DH, etc.
Molecular markers: SSR, CAPS AFLP, RFLP, RAPD, etc.
Generally, flanking markers 5-10 cm away from the target gene can be screened out through preliminary positioning.
Build A Linkage Map Integrate existing genetic maps and integrate different types of molecular markers
For species that have been sequenced, new analysis markers are designed based on DNA sequences near the gene of interest
Use the collinearity of comparative genomes to obtain molecular markers from other organisms in the same family and genus
Fine Positioning Use flanking markers to screen out recombinant individual plants, then use all polymorphic markers to analyze the recombinant individual plants, and combine the phenotypic identification results to locate the target gene within a range of 0.5 cm or less.
Physical Map Construction The difference in recombination values of different chromosome segments will affect the size of the genetic distance, so the distance between the molecular marker and the target gene should be calculated based on the actual number of bases.
Chromosome Walking Use the molecular markers most closely linked to both sides of the target gene to screen the positive clones in the large fragment DNA library and find the corresponding large fragment clones. Chromosome walking is then performed from both ends until a large fragment clone or spanning stack with molecular markers on both sides of the target gene is obtained.
Identify Candidate Genes Use large fragment clones containing the target gene, such as BAC or YAC clones, to screen the cDNA library, and query the biological data information database to determine candidate genes. Then,
(1) Whether cDNA and target gene are co-segregated
(2) Whether the spatiotemporal expression of cDNA is consistent with the phenotype
(3) Determine the cDNA sequence and query the database to understand the function of the gene
(4) Screen the mutant library to find out the changes in DNA sequence and their relationship with function
(5) Perform functional complementary verification
Functional Complementation Verification Functional complementation testing (transgenicity) is the most direct and conclusive way to identify genes
RNA interference (RNAi) can also be used to effectively identify target genes

While cloning of QTLs requires information of both genetic and physical maps, and is performed following a series of steps:

  • Identification of linkage group: Both gynogenic half-tetrad diploids and bulked segregant analysis (BSA) can be used.
  • Construction of genetic map.
  • Conversion of the genetic map to a physical map.
  • Construction of fine-scale physical map.
  • Candidate gene selection.
  • Validation of candidate QTLs function.

At Lifeasible, our teams of geneticists, statisticians, and software engineers will work closely toward the most optimized solvent for any given project, providing both scientific and technical insights for population type, sample size, marker collection, and other critical aspects of the positional cloning program, to ensure the success of your projects.

Welcome to contact us for technical consulting, experimental design, and other informations. We are always happy to walk you through our featured technologies, service plans, collaboration options, and more.

Why Choose Lifeasible?

01

Design optimized solutions based on different projects

02

Diverse services support research in plant breeding

03

Experienced teams of scientists and experts support client' projects

04

Efficient and reliable service

Related Services

Lifeasible provides comprehensive plant breeding services to support customers' related projects, including traditional breeding techniques and modern molecular breeding techniques. We also provide diversified plant analysis services.

Our products/services are For Research Use Only. Not For Clinical Use!
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