scholarly journals Molecular Population Genetics of Floral Homeotic Loci: Departures From the Equilibrium-Neutral Model at the APETALA3 and PISTILLATA Genes of Arabidopsis thaliana

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 839-848 ◽  
Author(s):  
Michael D Purugganan ◽  
Jane I Suddith

Abstract Molecular variation in genes that regulate development provides insights into the evolutionary processes that shape the diversification of morphogenetic pathways. Intraspecific sequence variation at the APETALA3 and PISTILLATA floral homeotic genes of Arabidopsis thaliana was analyzed to infer the extent and nature of diversity at these regulatory loci. Comparison of AP3 and PI diversity with three previously studied genes revealed several features in the patterning of nucleotide polymorphisms common between Arabidopsis nuclear loci, including an excess of low-frequency nucleotide polymorphisms and significantly elevated levels of intraspecific replacement variation. This pattern suggests that A. thaliana has undergone recent, rapid population expansion and now exists in small, inbred subpopulations. The elevated intraspecific replacement levels may thus represent slightly deleterious polymorphisms that differentiate distinct ecotypes. The distribution of replacement and synonymous changes in AP3 and PI core and noncore functional domains also indicates differences in the patterns of molecular evolution between these interacting floral regulatory genes.

2004 ◽  
Vol 1 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Hao Gang-Ping ◽  
Wu Zhong-Yi ◽  
Chen Mao-Sheng ◽  
Cao Ming-Qing ◽  
Dominique Brunel ◽  
...  

AbstractThe levels of drought tolerance and nucleotide polymorphism at the CBF4 locus were examined in a world-wide sample of 17 core accessions of Arabidopsis thaliana. The results showed that different accessions exhibited considerable differences in adaptation to drought stress. Compared with Columbia accession, the frequency of nucleotide polymorphism at the CBF4 locus of 25av, 203av and 244av accessions, including single nucleotide polymorphism (SNP) and insertion/deletion (Indel), was high, on average 1 SNP per 35.8 bp and 1 Indel per 143 bp. No significance in all regions of Tajima's D test indicated that the neutral mutation hypothesis could explain the nucleotide polymorphism in this CBF4 gene region. The higher polymorphism was the result of purification selection. Nucleotide polymorphism in the non-coding region was three times higher than in the coding region. This might indicate a recent relaxation of selection pressures on the non-coding region of CBF4 gene. In the coding region of CBF4, SNP frequency was 1 SNP per 96.4 bp and one non-synonymous mutation was detected from 25av, 203av and 244av accessions: the amino acid variation gly↔val at position 205, caused by the nucleotide variation G↔T at position 1034 (corresponding to the nucleotide at position 19 696 of GenBank accession no. AB015478 as 1). Furthermore, four differential SNPs were discovered in haplotype 6 constituted by 203av, one of them located in the 3′ non-coding region (A↔C at position 1106) and the others in the 5′ non-coding region (A↔G, A↔C and G↔A at positions 27, 129 and 171, respectively). The drought tolerance assay indicated that accession 203av was the best at tolerating water deficiency. We propose that haplotype 6 is consistent with its drought tolerance.


2012 ◽  
Vol 81 (2) ◽  
pp. 204-212 ◽  
Author(s):  
Tomoya Niki ◽  
Masayo Hirai ◽  
Tomoko Niki ◽  
Akira Kanno ◽  
Takaaki Nishijima

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4260
Author(s):  
Liana Najjar ◽  
Joshua Sutherland ◽  
Ang Zhou ◽  
Elina Hyppönen

Several observational studies have examined vitamin D pathway polymorphisms and their association with type 1 diabetes (T1D) susceptibility, with inconclusive results. We aimed to perform a systematic review and meta-analysis assessing associations between selected variants affecting 25-hydroxyvitamin D [25(OH)D] and T1D risk. We conducted a systematic search of Medline, Embase, Web of Science and OpenGWAS updated in April 2021. The following keywords “vitamin D” and/or “single nucleotide polymorphisms (SNPs)” and “T1D” were selected to identify relevant articles. Seven SNPs (or their proxies) in six genes were analysed: CYP2R1 rs10741657, CYP2R1 (low frequency) rs117913124, DHCR7/NADSYN1 rs12785878, GC rs3755967, CYP24A1 rs17216707, AMDHD1 rs10745742 and SEC23A rs8018720. Seven case-control and three cohort studies were eligible for quantitative synthesis (n = 10). Meta-analysis results suggested no association with T1D (range of pooled ORs for all SNPs: 0.97–1.02; p > 0.01). Heterogeneity was found in DHCR7/NADSYN1 rs12785878 (I2: 64.8%, p = 0.02). Sensitivity analysis showed exclusion of any single study did not alter the overall pooled effect. No association with T1D was observed among a Caucasian subgroup. In conclusion, the evidence from the meta-analysis indicates a null association between selected variants affecting serum 25(OH)D concentrations and T1D.


2018 ◽  
Vol 118 (08) ◽  
pp. 1382-1389 ◽  
Author(s):  
Christina Lind-Halldén ◽  
Eric Manderstedt ◽  
Daniel Carlberg ◽  
Stefan Lethagen ◽  
Christer Halldén

Abstractvon Willebrand factor (VWF) levels in healthy individuals and in patients with type 1 von Willebrand disease (VWD) are influenced by genetic variation in several genes, for example, VWF, ABO and STXBP5. Here, we comprehensively screen for STXBP5 variants and investigate their association with type 1 VWD in Swedish patients and controls. The coding region of the STXBP5 gene was re-sequenced in 107 type 1 VWD patients and the detected variants were genotyped in the type 1 VWD population and a Swedish control population (464 individuals). The functional effects of missense alleles were predicted in silico and the pattern of genetic variation in STXBP5 was analysed. Re-sequencing of 107 type 1 VWD patients identified three missense and three synonymous variants in the coding sequence of STXBP5. The low-frequency missense variants rs144099092 (0.005) and rs148830578 (0.029) were predicted to be damaging, but were not accumulated in patients. No other rare candidate mutations were detected. STXBP5 showed a high level of linkage disequilibrium and a low overall nucleotide diversity of π = 3.2 × 10−4 indicating intolerance to variants affecting protein function. Three previously type 1 VWD-associated single nucleotide polymorphisms were located on one haplotype that showed an increased frequency in patients versus controls. No differences in messenger ribonucleic acid abundance among haplotypes could be found using Genotype-Tissue Expression project data. In conclusion, a haplotype containing the STXBP5 Asn436Ser (rs1039084) mutation is associated with type 1 VWD and no rare STXBP5 mutations contribute to type 1 VWD in the Swedish population.


2010 ◽  
Vol 67 (11) ◽  
pp. 1827-1839 ◽  
Author(s):  
Patrick M. Gaffney ◽  
Carita M. Pascal ◽  
Jeffery Barnhart ◽  
W. Stewart Grant ◽  
James E. Seeb

We assessed genetic differentiation among populations of weathervane scallop ( Patinopecten caurinus ) in the northeastern Pacific, extending over 2500 km in the Gulf of Alaska and southeastern Bering Sea. Variability was surveyed at nuclear loci with allozyme, microsatellite, and single nucleotide polymorphism (SNP) methods, and at mitochondrial (mt)DNA loci with SNPs and nucleotide sequencing. High levels of gene diversity were detected for allozymes (H = 0.080), microsatellites (H = 0.734), and mtDNA (h = 0.781). Genotypes at nuclear loci generally fit Hardy–Weinberg proportions, except for some microsatellite loci, for which null-allele frequencies of 0.02 to 0.34 were estimated. No allele-frequency differences were detected among samples, except for the allozyme loci Gpi and Pep-4. Overall levels of differentiation ranged from FST = 0.0004 for allozymes, FST = 0.0008 for mtDNA to FST = 0.0004 for microsatellites. No isolation by distance was found for any of the markers. A unimodal mtDNA mismatch distribution and significant excesses of low-frequency variants for allozymes, microsatellites, and mtDNA may reflect a post-glacial population expansion. The lack of genetic differentiation measured by neutral markers does not preclude the existence of locally adapted, self-sustaining populations that are important in the harvest management of this species.


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