[Analysis of distribution characteristics and influencing factors of chord µ in young myopia].

Objective: To explore and analyze the distribution characteristics of chord µ related parameters, as well as the pupil center's relative position to the coaxial corneal light reflex on the corneal surface, and the influencing factors in young myopia. Methods: This was a cross-sectional study. A total of 761 myopic patients (761 eyes) were collected from March 2021 to December 2021 in the Refractive Surgery Center of Tianjin Eye Hospital, including 388 males and 373 females, with an average age of (24±6) years. The relationship between age, sex, diopter, anterior and posterior corneal surface parameters, and chord µ related parameters was analyzed, including the x and y absolute values of the pupil center, chord µ length, and angle. The normality of the data was tested using the Kolmogorov-Smirnov test, and the influencing factors of chord µ were analyzed through Pearson and Spearman correlation analysis. Results: The equivalent spherical degree and chord µ length were (-5.47±1.66) D and (0.178±0.095) mm, respectively. The chord µ length followed an approximately normal distribution. The chord µ length of 266 eyes (35%) was distributed in the range of 0.120 to 0.200 mm, while the chord µ length of 479 eyes (63%) was<0.200 mm, and the chord µ length of 620 eyes (81%) was<0.260 mm. The chord µ angle distribution accounted for the largest proportion in the superior nasal quadrant (45.6%), followed by the superior temporal quadrant (34.3%), the inferior temporal quadrant (10.1%), and the inferior nasal quadrant (10.0%). High myopia (r=0.11, P=0.002) and high astigmatism (r=0.08, P=0.023) were associated with an increase in chord µ length. The higher the degree of myopia, the smaller the chord µ angle (r=-0.09, P=0.019). The larger the ISV (r=0.09, P=0.017), IVA (r=0.08, P=0.025), and IHD (r=0.08, P=0.039) on the anterior surface of the cornea, the longer the chord µ length. The higher the astigmatism of the posterior corneal surface, the greater the absolute value of the Y coordinate of the pupil center (r=0.07, P=0.044), and the longer the chord µ length (r=0.08, P=0.035), and the smaller the chord µ angle (r=-0.08, P=0.032). Conclusions: The chord µ length of young myopic individuals in China followed an approximately normal distribution, with the majority located in the superior nasal and superior temporal quadrants. High myopia, high astigmatism, and irregular corneal shape are the main factors related to an increase in chord µ length.

Association of SNPs in PLA2R1 with idiopathic and secondary membranous nephropathy in two Chinese cohorts.

Objectives: Specific single-nucleotide polymorphisms (SNPs) in the M-type phospholipase A2 receptor-1 (PLA2R1) are associated with increased risk of idiopathic membranous nephropathy (IMN) in European populations. We hypothesized links between IMN and SMN with these SNPs in two Chinese cohorts.Methods: A cohort of 166 IMN patients and 144 controls from southern China (Group A) and a cohort of 212 IMN patients, 118 SMN patients, and 162 controls from northwestern China (Group B) were recruited. SNPs within PLA2R1 (rs3749119, rs3749117, rs35771982, rs3828323, and rs4664308) were identified and the frequencies of genotypes and alleles were determined for the different groups.Results: Relative to controls, IMN patients had a greater prevalence of rs35771982, rs3749117, and rs4664308 in Group A (OR = 1.61, 95% CI = 1.13-2.31, P = 0.011; OR = 1.62 (1.15-2.29), P = 0.006 and OR = 1.17 (1.06-1.28), P = 0.001, respectively) and in Group B (OR = 1.58 (1.13-2.22), P = 0.009; OR = 1.68 (1.22-2.33), P = 0.002 and OR = 1.15 (1.06-1.25), P < 0.001, respectively). Genotype and allele distributions of rs4664308 differed significantly between SMN patients and controls in Group B (OR = 1.58 (1.10-2.26), P = 0.012). Genotype and allele distribution of rs35771982 and rs4664308 differed significantly between PLA2R-Ab(+) and PLA2R-Ab(-) IMN patients in Group B (OR = 1.59 (1.09-2.31), P = 0.018 and OR = 1.15 (1.03-1.29), P = 0.005, respectively).Conclusion: This study of two cohorts from different regions of China indicate that specific PLA2R1 polymorphisms are associated with IMN and SMN.

Genetic diversity and genetic structure of consecutive breeding generations of golden mandarin fish (Siniperca scherzeri Steindachner) using microsatellite markers.

In this study, 12 polymorphic microsatellites were inves-tigated to determine the genetic diversity and structure of 5 consecu-tive selected populations of golden mandarin fish (Siniperca scherzeri Steindachner). The total numbers of alleles, average heterozyosity, and average polymorphism information content showed that the genetic diversity of these breeding populations was decreasing. Additionally, pairwise fixation index FST values among populations and Da values in-creased from F1 generation to subsequent generations (FST values from 0.0221-0.1408; Da values from 0.0608-0.1951). Analysis of molecular variance indicated that most genetic variations arise from individuals within populations (about 92.05%), while variation among populations accounted for only 7.95%. The allele frequency of the loci SC75-220 and SC101-222 bp changed regularly in the 5 breeding generations. Their frequencies were gradually increased and showed an enrichment trend, indicating that there may be genetic correlations between these 2 loci and breeding traits. Our study indicated that microsatellite markers are effective for assessing the genetic variability in the golden mandarin fish breeding program.

Microsatellite analysis of genetic diversity and genetic structure in five consecutive breeding generations of mandarin fish Siniperca chuatsi (Basilewsky).

In this report, 10 polymorphic microsatellites were applied to assess the genetic diversity and genetic differentiation of 5 consecutive breeding generations of mandarin fish, Siniperca chuatsi (Basilewsky). The results from total number of alleles, average polymorphism information content, and average homozygosity and heterozygosity showed that the genetic diversity of the breeding population was decreasing. The genetic identity between F1 and its descendant generations (F2, F3, F4, F5) decreased (from 0.9248 to 0.8803), while the genetic distance (from 0.0782 to 0.1275) and fixation index (from 0.03796 to 0.07393) increased. The allele frequency of SS181-235 and SS211-246 changed regularly in the 5 breeding generations, and they may be negatively associated with the selected trait, which needs to be confirmed by further research. Our study indicated that selective breeding was an efficient strategy for mandarin fish. In the process of breeding, some deleterious genes were phased out, and the genetic structure of the breeding populations became stable.

Isolation and characterization of polymorphic EST-SSR and genomic SSR markers in spotted mandarin fish (Siniperca scherzeri Steindachne).

Spotted mandarin fish (Siniperca scherzeri Steindachne) feed solely on live fry of other fish species once the fry start feeding in the wild. In the present study, 26 polymorphic transcriptome-derived simple sequence repeat (SSR) markers and 14 genomic SSR markers were developed and characterized in S. scherzeri Steindachne by combining a biotin-enrichment protocol and transcriptome of F1 interspecies hybrids between S. chuatsi (♀) and S. scherzeri (♂). These 40 polymorphic SSRs amplified 168 alleles (mean 4.2). The number of alleles, observed heterozygosity, expected heterozygosity, and polymorphic information content per locus were in the range of 2 to 7 (mean 4.3), 0.1111 to 1.000 (mean 0.6718), 0.3118 to 0.8276 (mean 0.6901), and 0.2735 to 0.7902 (mean 0.6298), respectively. Ten of these microsatellite loci deviated significantly from Hardy-Weinberg equilibrium (P < 0.00125) after Bonferroni correction for multiple tests and no significant linkage disequilibrium (P < 0.00006) was observed. The microsatellite markers characterized from S. scherzeri could be a valuable tool in genetic evaluation for conservation and for assessment of the mechanism associated with unique food preference of S. scherzeri from a genetic point of view.

Development and characterization of novel SSR markers in Siniperca kneri Garman.

In this study, 37 transcriptome-derived simple sequence repeat (SSR) markers and 18 genomic SSR markers were developed and characterized in the Chinese perch, Siniperca kneri Garman. The average allele number per locus was 5.1 (range: 2-8) for transcriptome-derived SSRs and 3.8 (range: 2-5) for genomic SSRs. The average observed and expected heterozygosities were 0.666 (range: 0.000-1.000) and 0.692 (range: 0.230-0.857) for transcriptome-derived SSRs, respectively. These values were 0.380 (range: 0.000-1.000) and 0.527 (range: 0.201-0.799) for genomic SSRs, respectively. The average polymorphic information content was 0.638 (range: 0.215-0.824) for transcriptome-derived SSRs and 0.477 (range: 0.183-0.752) for genomic SSRs. Seven of these loci exhibited departure from Hardy-Weinberg equilibrium after sequential Bonferroni's correction for multiple tests, and no significant deviation was observed for the linkage disequilibrium. These developed and characterized markers are anticipated to be useful for studies on population genetics, conservation genetics, and the fishery management of this species.

New microsatellite loci for the mandarin fish Siniperca chuatsi and their application in population genetic analysis.

The mandarin fish is a popular fresh water food fish in China. Fifty-three polymorphic microsatellite markers were isolated through construction of an enriched library of genomic DNA of Siniperca chuatsi (Percichthyidae). We found 2 to 7 alleles per locus. The observed and expected heterozygosity values varied from 0.059 to 1.000 and from 0.305 to 0.818, respectively. The polymorphic information content value varied from 0.255 to 0.782. Twelve microsatellite loci deviated significantly from Hardy-Weinberg equilibrium after Bonferroni's correction. These markers were evaluated in five species of sinipercine fish; 98% of the 265 locus/taxon combinations tested gave cross-amplification. Eight polymorphic microsatellite markers were randomly selected for genetic characterization of three S. chuatsi populations. The Ganjiang River and Yuanjiang River populations had moderate levels of genetic diversity, while the Mudanjiang River population had a relatively low level genetic diversity. Genetic distance-based cluster analysis showed clustering of the Ganjiang River and Yuanjiang River populations in a single group and the Mudanjiang River population in a separate group. Based on these results, we suggest that S. chuatsi from the Yangtze River watershed are distinct from the Mudanjiang River population. These SSR markers will be useful for diversity, mapping and marker assisted studies of S. chuatsi and other sinipercine fishes.