[Chromosome abnormality rate and related factors of spontaneous abortion in early pregnancy].

Objective: To investigate chromosome abnormality rate and related factors of spontaneous abortion in early pregnancy. Methods: A total of 831 tissue samples of spontaneous abortion in early pregnancy were collected from June 2015 to August 2018 in the First Affiliated Hospital of Nanjing Medical University. Chromosomal copy number was analyzed by next generation sequencing (NGS). The relationships between chromosome abnormality and maternal age, in vitro fertilization-embryo transfer (IVF-ET) pregnancy, number of previous spontaneous abortions, history of live birth were analyzed by statistical methods. Results: Among 831 tissue samples of spontaneous abortion in early pregnancy, 461 (55.5%, 461/831) were found to have chromosome abnormalities. Maternal age (OR=1.107, 95%CI: 1.070- 1.145) and history of live birth (OR=1.909, 95%CI: 1.182-3.083) were the positive correlative factors of chromosome abnormality. Times of previous spontaneous abortion (OR=0.807, 95%CI: 0.702-0.928) and IVF-ET pregnancy (OR=0.554, 95%CI: 0.404-0.760) were the negative correlative factors of chromosome abnormality. Conclusions: Chromosome abnormality is an important cause of spontaneous abortion in early pregnancy. The rate of chromosome abnormality increases with the increase of maternal age and the history of live birth, and decreases with the increase of number of previous spontaneous abortion and IVF-ET pregnancy.

Phytophthora infestans isolates from Northern China show high virulence diversity but low genotypic diversity.

Phenotypic and genotypic characteristics of 48 Phytophthora infestans isolates, collected in five provinces in Northern China between 1997 and 2003, were determined and compared with reference isolates. Characterisation included mating type, virulence, mitochondrial DNA (mtDNA) haplotype and DNA fingerprinting patterns based on simple sequence repeats (SSR) and amplified fragment length polymorphisms (AFLP). All isolates had the A1 mating type, mtDNA haplotype IIa and an identical SSR genotype (designated as SG-01-01) that differed from SSR genotypes found in the reference isolates, including those representing the 'old' US-1 lineage that dominated the P. infestans population worldwide prior to 1980. In contrast, the virulence spectra were highly variable and virulence to all resistance genes present in the standard differential set (R1 to R11) was found. AFLP analysis revealed some diversity; eight different AFLP genotypes were found that could be grouped into two major clusters. This study shows that there is very little genotypic diversity in the P. infestans population in Northern China. The occurrence of many different races within this rather uniform population is discussed in the framework of recent insights into the molecular determinants of avirulence in potato-P. infestans'gene-for-gene' interactions.