Dataset Information

High-resolution genetic map for understanding the effect of genome-wide recombination rate on nucleotide diversity in watermelon.

ABSTRACT: We used genotyping by sequencing to identify a set of 10,480 single nucleotide polymorphism (SNP) markers for constructing a high-resolution genetic map of 1096 cM for watermelon. We assessed the genome-wide variation in recombination rate (GWRR) across the map and found an association between GWRR and genome-wide nucleotide diversity. Collinearity between the map and the genome-wide reference sequence for watermelon was studied to identify inconsistency and chromosome rearrangements. We assessed genome-wide nucleotide diversity, linkage disequilibrium (LD), and selective sweep for wild, semi-wild, and domesticated accessions of Citrullus lanatus var. lanatus to track signals of domestication. Principal component analysis combined with chromosome-wide phylogenetic study based on 1563 SNPs obtained after LD pruning with minor allele frequency of 0.05 resolved the differences between semi-wild and wild accessions as well as relationships among worldwide sweet watermelon. Population structure analysis revealed predominant ancestries for wild, semi-wild, and domesticated watermelons as well as admixture of various ancestries that were important for domestication. Sliding window analysis of Tajima's D across various chromosomes was used to resolve selective sweep. LD decay was estimated for various chromosomes. We identified a strong selective sweep on chromosome 3 consisting of important genes that might have had a role in sweet watermelon domestication.

SUBMITTER: Reddy UK

PROVIDER: S-EPMC4232547 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature

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High-resolution genetic map for understanding the effect of genome-wide recombination rate on nucleotide diversity in watermelon.

Reddy Umesh K UK Nimmakayala Padma P Levi Amnon A Abburi Venkata Lakshmi VL Saminathan Thangasamy T Tomason Yan R YR Vajja Gopinath G Reddy Rishi R Abburi Lavanya L Wehner Todd C TC Ronin Yefim Y Karol Abraham A

G3 (Bethesda, Md.) 20140915 11

We used genotyping by sequencing to identify a set of 10,480 single nucleotide polymorphism (SNP) markers for constructing a high-resolution genetic map of 1096 cM for watermelon. We assessed the genome-wide variation in recombination rate (GWRR) across the map and found an association between GWRR and genome-wide nucleotide diversity. Collinearity between the map and the genome-wide reference sequence for watermelon was studied to identify inconsistency and chromosome rearrangements. We assesse ...[more]

PMID: 25227227

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Project description:BACKGROUND: Polymorphism is key to the evolutionary potential of populations. Understanding which factors shape levels of genetic diversity within genomes forms a central question in evolutionary genomics and is of importance for the possibility to infer episodes of adaptive evolution from signs of reduced diversity. There is an on-going debate on the relative role of mutation and selection in governing diversity levels. This question is also related to the role of recombination because recombination is expected to indirectly affect polymorphism via the efficacy of selection. Moreover, recombination might itself be mutagenic and thereby assert a direct effect on diversity levels. RESULTS: We used whole-genome re-sequencing data from domestic chicken (broiler and layer breeds) and its wild ancestor (the red jungle fowl) to study the relationship between genetic diversity and several genomic parameters. We found that recombination rate had the largest effect on local levels of nucleotide diversity. The fact that divergence (a proxy for mutation rate) and recombination rate were negatively correlated argues against a mutagenic role of recombination. Furthermore, divergence had limited influence on polymorphism. CONCLUSIONS: Overall, our results are consistent with a selection model, in which regions within a short distance from loci under selection show reduced polymorphism levels. This conclusion lends further support from the observations of strong correlations between intergenic levels of diversity and diversity at synonymous as well as non-synonymous sites. Our results also demonstrate differences between the two domestic breeds and red jungle fowl, where the domestic breeds show a stronger relationship between intergenic diversity levels and diversity at synonymous and non-synonymous sites. This finding, together with overall lower diversity levels in domesticates compared to red jungle fowl, seem attributable to artificial selection during domestication.

Dataset Information

High-resolution genetic map for understanding the effect of genome-wide recombination rate on nucleotide diversity in watermelon.

Publications

High-resolution genetic map for understanding the effect of genome-wide recombination rate on nucleotide diversity in watermelon.

Similar Datasets

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