Next Generation Sequencing-Based Molecular Marker Development: A Case Study in Betula Alnoides

Area of Science:

• Genetics
• Molecular Biology
• Forestry

Background:

• Betula alnoides is a fast-growing, valuable indigenous tree species in tropical and subtropical Asia.
• The species is predominantly tetraploid in China, highlighting the need for genetic research.

Purpose of the Study:

• To develop novel simple sequence repeat (SSR) markers for Betula alnoides using next-generation sequencing (NGS).
• To assess the genetic diversity and polymorphism of B. alnoides using the developed SSR markers.
• To evaluate the cross-species transferability of these SSR markers to related Betula species.

Main Methods:

• Next-generation sequencing (NGS) was employed to identify SSR loci in Betula alnoides.
• Primer sets were designed for putative SSR regions, and 900 were randomly selected for amplification and polymorphism analysis.
• Genetic diversity was quantified using parameters such as the number of alleles, observed and expected heterozygosities, and Shannon-Wiener diversity index.
• Cross-species transferability was tested on six related Betula species.

Main Results:

• NGS identified 164,357 candidate SSR loci from 106,452 clean reads.
• Mononucleotide repeats were most abundant (77.05%), followed by dinucleotide (10.18%).
• Out of 900 tested primer sets, 310 polymorphic SSR markers were identified.
• The developed markers revealed significant genetic diversity within B. alnoides populations (mean alleles=5.14, mean H_O=0.64, mean H_E=0.57, mean I=1.12).
• Successful cross-species amplification ranged from 48.96% to 84.38% for tested Betula species.

Conclusions:

• The study successfully developed a substantial set of polymorphic SSR markers for Betula alnoides.
• These SSR markers provide valuable tools for population genetics studies and molecular marker-assisted breeding.
• The markers demonstrate potential for genome-wide association studies and conservation efforts in Betula species.