Survey of microsatellite DNA in pine

Area of Science:

• Genetics
• Molecular Biology
• Forestry

Background:

• Microsatellites, or simple sequence repeats (SSRs), are valuable genetic markers.
• Understanding microsatellite distribution is crucial for marker development in forest trees.

Purpose of the Study:

• To investigate the abundance and distribution of various microsatellite motifs in two pine species: eastern white pine (Pinus strobus) and loblolly pine (Pinus taeda).
• To identify suitable microsatellite motifs for developing genetic markers in pines.

Main Methods:

• Probing genomic libraries of eastern white pine and loblolly pine with various di-, tri-, and tetranucleotide microsatellite motifs.
• Quantifying the abundance of identified microsatellite loci per megabase pair (Mbp).

Main Results:

• The four most abundant microsatellite motifs in both species were (AC)n, (AG)n, (AAT)n, and (ATC)n, collectively comprising over half of the investigated sites.
• (AC)n and (AG)n dinucleotides were the most abundant, with densities of 2-4.5 sites/Mbp.
• Eastern white pine showed a higher abundance of (AC)n repeats compared to (AG)n, unlike loblolly pine and most other plants.

Conclusions:

• Dinucleotide and trinucleotide microsatellites, particularly (AC)n, (AG)n, (AAT)n, and (ATC)n, are abundant in pine genomes.
• These abundant microsatellites are excellent candidates for developing robust genetic markers for Pinus species.
• The distinct distribution of (AC)n and (AG)n in eastern white pine warrants further investigation for population genetics studies.