[Design and exploration of genetic experiments for non-Mendelian segregation].

It has always been a challenge to combine research progress with undergraduate laboratory teaching. Herein we designed a comprehensive experiment to compare classical Mendelian segregation and non-Mendelian distorted segregation by utilizing a rice material (DSSL) containing F1 hybrid male sterility locus S23 constructed previously in our research project. Using the four SSR markers located on two chromosomes of rice, the genotypes of the F2 population and the two parents were analyzed, and the phenotypes of the pollen fertility of the two parents and their F1 plants were investigated. The results not only verified segregation law at the molecular level, but also fully demonstrated the distorted segregation in both genotypes and phenotypes, thus deepening students' understandings of plant genetics and the relationship between genotypes and phenotypes, inspiring students' interests in genetics experiments, and enhancing students' consciousness and enthusiasm for experimental learning. On the basis of this, a sustainable development idea of transforming scientific research progress into teaching applications was conceived to promote the reform and innovation of genetics laboratory teaching.

Crossability barriers in the interspecific hybridization between Oryza sativa and O. meyeriana.

Oryza meyeriana Baill (GG genome) is a precious germplasm in the tertiary gene pool of cultivated rice (AA genome), and possesses important traits such as resistance and tolerance to biotic and abiotic stress. However, interspecific crossability barrier, a critical bottleneck restricting genes transfer from O. meyeriana to cultivars has led to no hybrids through conventional reproduction. Therefore, the reasons underlying incrossability were investigated in the present report. The results showed that: (i) at 3-7 d after pollination (DAP), many hybrid embryos degenerated at the earlier globular-shaped stage, and could not develop into the later pear-shaped stage. Meanwhile, free endosperm nuclei started to degenerate at 1 DAP, and cellular endosperm could not form at 3 DAP, leading to nutrition starvation for young embryo development; (ii) at 11-13 DAP, almost all hybrid ovaries aborted. Even though 72.22% of hybrid young embryos were produced in the interspecific hybridization between O. sativa and O. meyeriana, young embryos were not able to further develop into hybrid plantlets via culturing in vitro. The main reason for the incrossability was hybrid embryo inviability, presenting as embryo development stagnation and degeneration since 3 DAP. Some possible approaches to overcome the crossability barriers in the interspecific hybridization between O. sativa and O. meyeriana are discussed.

[Study of association of platelet endothelial cell adhesion molecule-1 gene polymorphism with acute myocardial infarction].

OBJECTIVE: To investigate the association of single nucleotide polymorphism (SNP) and its haplotypes of platelet endothelial cell adhesion molecule-1 (PECAM-1) gene with susceptibility to acute myocardial infarction (AMI), and to analyze association the serum levels and genotypes of PECAM-1 with AMI. METHODS: Three SNPs of PECAM-1 gene Leu125Val, Asn563Ser and Gly670Arg were analyzed in 180 patients with AMI and 200 age and sex matched controls, using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy, and the serum level of PECAM-1 was determined by enzyme linked immunosorbent assay (ELISA). Frequency of haplotypes and linkage disequilibrium of PECAM-1 gene in different groups were analyzed by SHEsis programs. RESULTS: The distributions of PECAM-1 gene Asn563Ser and Gly670Arg polymorphisms were not different between AMI and control group (P>0.05), but the PECAM-1 gene Leu125Val polymorphism was significantly different (P<0.05). The relative risk suffered from AMI of Val allele was 1.480 folds of the Leu allele carriers [odds ratio (OR)=1.480, 95% confidence interval (CI): 1.111-1.972, P=0.007]; the serum level of PECAM-1 Val allele carriers was significantly higher than that of noncarriers (P<0.01). With the results of the genotyping analyses, PECAM-1 gene Leu125Val, Asn563Ser and Gly670Arg polymorphisms showed strong linkage disequilibrium, and the Val-Ser-Arg haplotype was associated with a significantly increased risk of AMI as compared with the controls (OR=1.489, 95%CI: 1.118-1.984, P=0.006). CONCLUSION: PECAM-1 gene Leu125Val polymorphism and its Val-Ser-Arg haplotype are associated with AMI, Val allele is an important genetic susceptibility gene for AMI. The PECAM-1 Val allele carriers may have a higher risk by enhancing the PECAM-1 expression in the pathogenesis of AMI.