Related Experiment Video
Updated: May 5, 2026

Combined Immunofluorescence and DNA FISH on 3D-preserved Interphase Nuclei to Study Changes in 3D Nuclear Organization
Published on: February 3, 2013
[Calculation of likelihood ratio for X-STR typing in kinship testing]
Yin-Ming Zhang1, Li Li, Hong-Yu Sun
1Department of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China. fayizym@163.com
Objective:
To deduce the calculation formulae of likelihood ratio for kinship testing with X-short tandem repeat (X-STR) typing.
Methods:
With the identity by decent coefficient of different relationships, the joint genotypic probability of two individuals with specific genotypes was calculated as X value, and then the joint genotypic probability of two unrelated individuals was calculated as Y value; therefore, the likelihood ratio value (X/Y) was obtained.
Results:
The calculation formulae of the likelihood ratio for different genotype combinations of the female-female, female-male and male-male genetic relationships were derived and verified by real cases.
Conclusion:
The calculation formulae are simple and accurate to evaluate the likelihood ratio for two individuals' genetic relationship with X-STR typing. The formulae provide the basic potential value for the difficult kinship testing with X-STR loci.
More Related Videos
Related Concept Videos
Probability Laws
The Ratio of X Chromosome to Autosomes
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female...
Chi-square Analysis
The chi-square test was developed by Pearson in 1990.
The first step of performing a Chi-square analysis is to establish a null hypothesis, which assumes that there is no real...
Test for Homogeneity
Hardy-Weinberg Principle
Punnett Squares

