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- Banabazi, Mohammad Hossein
(författare)
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Population genetic analysis and scans for adaptation and contemporary selection footprints provide genomic insight into aus, indica and japonica rice cultivars diversification
- 2023
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Ingår i: Journal of Genetics. - 0022-1333 .- 0973-7731. ; 102
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Tidskriftsartikel (refereegranskat)abstract
- Following domestication, rice cultivars have been spread worldwide to different climates and have experienced selection pressures to improve desirable traits. This has resulted in diverse cultivars that display variations in phenotypic traits, such as stress tolerance, grain size, and yield. To better understand the genomic composition arising from cultivar's development and local adaptation, high-density genotypes (containing 286,183 single-nucleotide polymorphisms after the quality control) of 1284 rice cultivars of aus, indica, and temperate and tropical japonica were scanned for diversifying signatures by applying a pairwise comparison of fixation index (Fst) test. Each cultivar's population was investigated for contemporary selection using the integrated haplotype score test. Signatures of diversifying selection among the pairwise comparisons were found in genomic regions mainly involved in response to stress (pathogens, drought, heat, cold) and development and morphology of various structures, such as root, pollen, spikelet, and grain. The most significant diversification signal between indica and japonica cultivars was detected at the location of ROX2 gene. Aus with indica comparison detected the most divergent signal at important candidate genes of OsEXPA8 and OsEXPA9, whereas temperate with tropical japonica comparison resulted in two well-known candidate genes OsHCT4 and OsGpx4. Recent selection analysis detected different patterns of contemporary selection in genomic regions related to rice breeding standard criteria such as stress tolerance, seed germination, starch content, and flowering time. Our findings highlight the underlying molecular basis of adaptive divergence and propose that modern rice breeding may provide additional diversification among rice cultivars.
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- Lankinen, Åsa
(författare)
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Upper petal lip colour polymorphism in Collinsia heterophylla (Plantaginaceae): genetic basis within a population and its use as a genetic marker.
- 2009
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Ingår i: Journal of Genetics. - : Springer Science and Business Media LLC. - 0022-1333 .- 0973-7731. ; 88:2, s. 205-215
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the genetics of a polymorphic trait is important to predict its likely evolution. In Collinsia heterophylla, the upper petal lip colour can be either be white or white with a purple band, while the lower petal lip colour is invariably purple. Because the corolla is only partly polymorphic, the polymorphism can not have evolved due to a mutation where a pigment was lost in the entire plant, which is common in other polymorphic species. In a previous study, high frequency of the purple band was found in populations with darker flowers, indicating possible selection for this trait. In this study, I determined inheritance of the colour polymorphism using two populations (one with only white morph and other with both morphs). I conducted experimental crosses within and between floral morphs to determine whether patterns of segregation in offspring conform to single-gene predictions. Data from F1, F2, F3 and backcross progeny are consistent with a genetic model of one major locus with presence of the band being completely dominant, as indicated in earlier studies using distantly related populations. A novel finding in this study was that the two morphs did not show a difference in seed germination frequency or seedling survival. This trait can thus be valuable as a genetic marker. Even though more thorough ecological data are needed to understand the potential selection pressures on upper petal lip colour in C. heterophylla, its simple inheritance may indicate the possibility of fast evolutionary response to selective forces acting on this trait.
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