Systematic screening of sheep skin cDNA libraries for microsatellite sequences

Area of Science:

• Genomics
• Molecular Biology
• Animal Genetics

Background:

• Microsatellites, or simple sequence repeats (SSRs), are valuable genetic markers.
• Sheep (Ovis aries) possess a genome that benefits from detailed genetic mapping for agricultural and research purposes.

Purpose of the Study:

• To identify and characterize microsatellite repeat-containing clones from a large sheep cDNA library.
• To assess the non-redundancy and potential function of these clones.
• To develop novel ovine microsatellite markers and map them onto the sheep linkage map.

Main Methods:

• High-density gridding of 65,000 sheep skin cDNA clones on nylon membranes.
• Screening for (CA)n and (GA)n dinucleotide repeats.
• Single-pass 5' sequencing of identified clones to generate Expressed Sequence Tags (ESTs).
• Comparison of ESTs against the Swiss-Prot database for identity and function prediction.
• Alignment of ESTs to the human genome to identify orthologous sequences.
• Development and mapping of polymorphic microsatellite markers.

Main Results:

• 296 dinucleotide repeat-containing clones were identified.
• Approximately 85% of the identified clones were non-redundant.
• ESTs were compared to Swiss-Prot for putative functions.
• Human orthologous sequences were located.
• A subset of polymorphic microsatellite markers was developed and positioned on the ovine linkage map.

Conclusions:

• The study successfully identified and characterized a significant number of ovine microsatellite-containing clones.
• The generated ESTs provide insights into sheep gene identity and function.
• The developed microsatellite markers are valuable resources for ovine genetic mapping and future research.