title: Comparison of SSR and SNP markers in estimation of genetic diversity and population structure of Indian rice varieties.
abstract: Simple sequence repeat (SSR) and Single Nucleotide Polymorphic (SNP), the two most robust markers for identifying rice varieties were compared for assessment of genetic diversity and population structure. Total 375 varieties of rice from various regions of India archived at the Indian National GeneBank, NBPGR, New Delhi, were analyzed using thirty six genetic markers, each of hypervariable SSR (HvSSR) and SNP which were distributed across 12 rice chromosomes. A total of 80 alleles were amplified with the SSR markers with an average of 2.22 alleles per locus whereas, 72 alleles were amplified with SNP markers. Polymorphic information content (PIC) values for HvSSR ranged from 0.04 to 0.5 with an average of 0.25. In the case of SNP markers, PIC values ranged from 0.03 to 0.37 with an average of 0.23. Genetic relatedness among the varieties was studied; utilizing an unrooted tree all the genotypes were grouped into three major clusters with both SSR and SNP markers. Analysis of molecular variance (AMOVA) indicated that maximum diversity was partitioned between and within individual level but not between populations. Principal coordinate analysis (PCoA) with SSR markers showed that genotypes were uniformly distributed across the two axes with 13.33% of cumulative variation whereas, in case of SNP markers varieties were grouped into three broad groups across two axes with 45.20% of cumulative variation. Population structure were tested using K values from 1 to 20, but there was no clear population structure, therefore Ln(PD) derived Δk was plotted against the K to determine the number of populations. In case of SSR maximum Δk was at K=5 whereas, in case of SNP maximum Δk was found at K=15, suggesting that resolution of population was higher with SNP markers, but SSR were more efficient for diversity analysis.
authors.affiliation: Division of Genomic Resources, National Bureau of Plant Genetic Resources, New Delhi, Delhi, India.
authors.forename: Nivedita
authors.initials: N
authors.lastname: Singh
authors.affiliation: Division of Genomic Resources, National Bureau of Plant Genetic Resources, New Delhi, Delhi, India.
authors.forename: Debjani Roy
authors.initials: DR
authors.lastname: Choudhury
authors.affiliation: Division of Genomic Resources, National Bureau of Plant Genetic Resources, New Delhi, Delhi, India.
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Division of Genomic Resources, National Bureau of Plant Genetic Resources, New Delhi, Delhi, India.
authors.forename: Sundeep
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Germplasm Conservation Division, National Bureau of Plant Genetic Resources, New Delhi, Delhi, India.
authors.forename: Kalyani
authors.initials: K
authors.lastname: Srinivasan
authors.affiliation: Germplasm Conservation Division, National Bureau of Plant Genetic Resources, New Delhi, Delhi, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Tyagi
authors.affiliation: National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute, New Delhi, Delhi, India.
authors.forename: N K
authors.initials: NK
authors.lastname: Singh
authors.affiliation: Division of Genomic Resources, National Bureau of Plant Genetic Resources, New Delhi, Delhi, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Singh
mesh_terms: D005819:Genetic Markers / Q000235:genetics; D007194:India; D018895:Microsatellite Repeats; D012275:Oryza / Q000235:genetics*; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D011157:Population Dynamics; D013223:Statistics as Topic
chemical_list: D005819:Genetic Markers