Allelic variation for meiosis related genes in Brassica juncea and its diploid progenitors

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dc.contributor.advisorBanga, S.S.
dc.contributor.authorSnehdeep Kaur
dc.date.accessioned2016-11-08T14:17:59Z
dc.date.available2016-11-08T14:17:59Z
dc.date.issued2016
dc.description.abstractPatterns of allelic differentiation were investigated for meiotic genes in natural and resynthesized B. juncea allotetraploids as well as their progenitors. Pollen fertility was wide-ranging, with B. juncea showing the maximum variation. A representative set of 96 lines was then genotyped with 70 STS markers. Fifty five polymorphic markers amplified 137 alleles. Within population differences (76%) accounted for maximum variation, followed by variation among species (19%). Population structure analysis largely reflected the ploidy boundaries. Diploids were grouped together, but B. juncea formed two major subgroups. Linkage disequilibrium (LD) deviated significantly between species and subpopulations as well. Large LD block with MMD1 was observed for B. juncea. For diploids, MRE11 and TES spanned major LD blocks. Markers based on two candidate genes, SCC3 and BRCA2b showed significant association with pooled pollen fertility. These explained 11-14 % of the trait variation. For B. juncea, only MS5b provided evidence of directional selection using softwares Arlequin and LOSITAN. Tajima’s D values were negatively significant for RAD51C, ZYP1a and ZYP1b for A homolog, indicating balancing selection. B homolog of SWI1 showed evidence of positive selection. Hierarchical clustering analysis based on gene expression indicated diverse meiotic machinery in B. juncea as compared to progenitor species. MEI1, ZYP1a, ZYP1b were transgressively over expressed in B. juncea. In contrast; SPO11-1, DMC1, BRCA2a, MSH2, MSH4, MMD1 and TES were distinctly down regulated in B. juncea. There seemed to be a distinct balance between co-upregulation or –down regulation of identified meiotic genes in both natural and freshly resynthesized allopolyploids, suggesting that changes in gene expression regulation may occur in the early aftermath of genome merger.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/84463
dc.language.isoenen_US
dc.publisherPunjab Agricultural University, Ludhianaen_US
dc.research.problemAllelic variation for meiosis related genes in Brassica juncea and its diploid progenitorsen_US
dc.subPlant Breeding and Geneticsen_US
dc.subjectMeiotic genesen_US
dc.subjectBrassica junceaen_US
dc.subjectTranscriptomeen_US
dc.themeBrassica junceaen_US
dc.these.typeM.Sc
dc.titleAllelic variation for meiosis related genes in Brassica juncea and its diploid progenitorsen_US
dc.typeThesisen_US
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