title: Single Nucleotide Polymorphism Identification in Polyploids: A Review, Example, and Recommendations.
abstract: Understanding the relationship between genotype and phenotype is a major biological question and being able to predict phenotypes based on molecular genotypes is integral to molecular breeding. Whole-genome duplications have shaped the history of all flowering plants and present challenges to elucidating the relationship between genotype and phenotype, especially in neopolyploid species. Although single nucleotide polymorphisms (SNPs) have become popular tools for genetic mapping, discovery and application of SNPs in polyploids has been difficult. Here, we summarize common experimental approaches to SNP calling, highlighting recent polyploid successes. To examine the impact of software choice on these analyses, we called SNPs among five peanut genotypes using different alignment programs (BWA-mem and Bowtie 2) and variant callers (SAMtools, GATK, and Freebayes). Alignments produced by Bowtie 2 and BWA-mem and analyzed in SAMtools shared 24.5% concordant SNPs, and SAMtools, GATK, and Freebayes shared 1.4% concordant SNPs. A subsequent analysis of simulated Brassica napus chromosome 1A and 1C genotypes demonstrated that, of the three software programs, SAMtools performed with the highest sensitivity and specificity on Bowtie 2 alignments. These results, however, are likely to vary among species, and we therefore propose a series of best practices for SNP calling in polyploids.
authors: Institute of Plant Breeding, Genetics & Genomics, University of Georgia, Tifton, GA 31793, USA.
authors: Josh
authors: J
authors: Clevenger
authors: Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602, USA.
authors: Carolina
authors: C
authors: Chavarro
authors: Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602, USA.
authors: Stephanie A
authors: SA
authors: Pearl
authors: Institute of Plant Breeding, Genetics & Genomics, University of Georgia, Tifton, GA 31793, USA. Electronic address: pozias@uga.edu.
authors: Peggy
authors: P
authors: Ozias-Akins
authors: Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602, USA. Electronic address: sjackson@uga.edu.
authors: Scott A
authors: SA
authors: Jackson
mesh_terms: D010367:Arachis / Q000235:genetics*; D029688:Brassica napus / Q000235:genetics*; D059014:High-Throughput Nucleotide Sequencing; D010940:Plant Proteins / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011123:Polyploidy
chemical_list: D010940:Plant Proteins
keywords: genomics; homeolog; next-generation sequencing (NGS); peanut; polyploid; single nucleotide polymorphism (SNP)