Targeted oligonucleotide-mediated microsatellite identification (TOMMI) from large-insert library clones

Area of Science:

• Molecular genetics
• Genomics
• Animal breeding

Background:

• Microsatellites are preferred molecular markers for livestock genome mapping, biodiversity, and phylogeny.
• They offer advantages over single nucleotide polymorphisms (SNPs) due to multi-allelism and cost-effectiveness.
• Traditional microsatellite isolation is time-consuming and expensive.

Purpose of the Study:

• To introduce a novel sequencing approach for direct microsatellite generation from large-insert libraries.
• To develop an efficient and rapid flanking sequence-based method for isolating Sequence Tagged Site (STS) markers.
• To generate polymorphic microsatellite markers suitable for genetic studies.

Main Methods:

• Targeted oligonucleotide-mediated microsatellite identification (TOMMI) was used to isolate seventeen porcine microsatellite markers from eleven PAC clones.
• Microsatellite characterization included calculating the number of alleles, allele size distribution, polymorphism information content (PIC), heterozygosity (HT), and effective allele number (NE).
• The study analyzed 336 animals from fifteen pig breeds.

Main Results:

• TOMMI successfully identified an average of 1.55 (CA/GT) microsatellites per PAC clone.
• Sixteen of the seventeen markers were polymorphic, exhibiting 2 to 22 alleles.
• Fourteen markers produced amplicons of at least 200 bp, facilitating integration into multilocus assays and potential use in Quantitative Trait Loci (QTL) studies.

Conclusions:

• The described sequencing strategy is a targeted, inexpensive, and fast method for developing microsatellites from large-insert libraries.
• This approach is suitable for generating polymorphic markers for specific chromosomal regions and contigs.
• It yields high-quality sequence data for developing amplicons exceeding 250 bases.