Impact of the number of microsatellite markers on the analysis of population genetic diversity of Schistosoma japonicum
10.16250/j.32.1915.2025005
- VernacularTitle:微卫星位点标记数量对日本血吸虫种群 遗传多样性研究的影响
- Author:
Juan LONG
1
;
Lang MA
1
;
Hongying ZONG
2
;
Zhipeng ZHOU
3
;
Hao YAN
3
;
Qinping ZHAO
1
Author Information
1. Department of Human Parasitology, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan, Hubei 430071, China
2. Demonstration Center for Experimental Basic Medicine Education, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, China
3. Oncomelania Snails and Schistosoma Collection Base, National Parasitic Resource Bank, Gong’an County Ecological Station of Oncomelania Snails, Hubei Province, China
- Publication Type:Journal Article
- Keywords:
Schistosoma japonicum;
Cercaria;
Population structure;
Genetic diversity;
Microsatellite locus;
Allele;
Genetic polymorphism
- From:
Chinese Journal of Schistosomiasis Control
2025;37(3):239-246
- CountryChina
- Language:Chinese
-
Abstract:
Objective To examine the impact of different numbers of microsatellite markers on the analysis of population genetic diversity of Schistosoma japonicum, so as to provide insights into studies on the population genetic diversity of S. japonicum. Methods Oncomelania hupensis snails were collected from a wasteland in Gong’an County, Hubei Province, and 37 S. japonicum-infected O. hupensis snails were identified using the cercarial shedding method. A single cercaria released from each S. japonicum-infected O. hupensis snail was collected, and 10 cercariae were randomly collected from DNA extraction. Nine previously validated microsatellite loci and 15 additional microsatellite loci screened from literature review and the GenBank database and confirmed with stable amplification efficiency were selected as molecular markers. Genomic DNA from cercariae was subjected to three multiplex PCR amplifications of microsatellite markers with the Type-it Microsatellite PCR kit, and genotyped using capillary electrophoresis. The population genetic diversity of S. japonicum cercariae DNA was analyzed with observed number of alleles (Na), effective number of alleles (Ae), observed heterozygosity (Ho), expected heterozygosity (He), and polymorphism information content (PIC), and tested for Hardy-Weinberg equilibrium (HWE) and linkage disequilibrium (LD). To further investigate the impact of the number of microsatellite loci on the population genetic diversity of S. japonicum, the number of microsatellite markers was sequentially assigned from 1 to 24, and the mean and standard deviation of Na were calculated for S. japonicum populations at different locus numbers. In addition, the coefficient of variation (CV) of allelic number (defined as the ratio of the standard deviation to the mean) was determined, and the variation in Na with increasing microsatellite locus numbers was analyzed. Results Genomic DNA from 345 S. japonicum cercariae was selected for genotyping of 24 microsatellite markers, and all 24 microsatellite loci met linkage equilibrium (standardized linkage disequilibrium coefficient D′ < 0.7, r2 < 0.3) and deviated from Hardy-Weinberg equilibrium (P < 0.001). The mean Na, Ae, Ho and He were 27.46 ± 2.18, 12.46 ± 0.95, 0.46 ± 0.03, and 0.91 ± 0.01 for 24 microsatellite loci in S. japonicum cercarial populations, respectively, and PIC ranged from 0.85 to 0.96, indicating high genome-wide representativeness of 24 microsatellite loci. The mean value of Na-Ae was higher in genotyping with 9 previously validated microsatellite loci (19.88 ± 8.43) than with all 24 loci (14.99 ± 8.09). As the number of microsatellite loci increased, the mean Na showed no significant variation; however, the standard deviation gradually decreased. Notably, if the locus number reached 18 or more, the variation in the standard deviation of Na remarkably reduced. In addition, the standard deviation of Na at 18 loci was less than 5% of the mean Na at 24 loci, with a CV of 4.6%. Conclusions The number of microsatellite loci significantly affects the population genetic diversity analysis of S. japonicum. Eighteen or more microsatellite loci are recommended for analysis of the population genetic diversity of S. japonicum under the current conditions of low-prevalence infection and unbalanced genetic distribution of S. japonicum.
