Related Experiment Video
Updated: Jun 14, 2025

A Method to Define the Effects of Environmental Enrichment on Colon Microbiome Biodiversity in a Mouse Colon Tumor Model
Published on: February 28, 2018
[Causal relationship between relative abundance of gut microbiota and teratozoospermia: A two-sample Mendelian
Xiao-Hui Hao1, Rui-Min Ma1, Si-Cheng Ma1
1Henan University of Chinese Medicine, Zhengzhou, Henan 450046, China.
Objective:
To explore the potential causal relationship between gut microbiota and teratozoospermia.
Methods:
We searched the database of Genome-Wide Association Study (GWAS) for gut microbiota- and teratozoospermia-related data. We used gut microbiota as an exposure factor, determined the instrumental variables according to the GWAS data on 18 340 participants released by the MiBioGen Alliance, and derived the outcome variables from the European data on teratozoospermia, with a sample size of 85 716, including 915 cases and 209 006 controls. Using inverse-variance weighting (IVW), MR-Egger regression and the weighted median estimator (WME), we performed two-sample Mendelian randomization (MR) analysis on the retrieved data, and estimated the causal relationship between gut microbiota and teratozoospermia based on the β value.
Results:
Two-sample MR analysis indicated that the class Erysipelotrichia, family Erysipelotrichaceae, family Streptococcaceae, genus Coprococcusl, genus Ruminococcaceae UCG009, genus Streptococcus, order Clostridialesm and order Erysipelotrichales were causally related with the increased risk, while the family Porphyromonadaceae with the decreased risk of teratozoospermia.
Conclusion:
The class Erysipelotrichia, family Erysipelotrichaceae, family Streptococcaceae, genus Coprococcusl, genus Ruminococcaceae UCG009, genus Streptococcus, order Clostridialesm and order Erysipelotrichales are one of the causes of teratozoospermia, related to the increased risk of the condition, while the family Porphyromonadaceae has a protective effect on sperm morphology, reducing the risk of teratozoospermia.
Related Concept Videos
Infertility in Males
Testing a Claim about Population Proportion
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...
Testing a Claim about Mean: Known Population SD
Estimating a population mean requires the samples to be distributed normally. The data should be collected from the randomly selected samples having no sampling bias. The sample size needed to be higher than 30, and most importantly, the population standard deviation should be already known.
In most realistic situations, the population standard deviation is often unknown, but in rare circumstances, when it...

