Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

What is Population Genetics?01:25

What is Population Genetics?

59.0K
A population is composed of members of the same species that simultaneously live and interact in the same area. When individuals in a population breed, they pass down their genes to their offspring. Many of these genes are polymorphic, meaning that they occur in multiple variants. Such variations of a gene are referred to as alleles. The collective set of all the alleles within a population is known as the gene pool.
59.0K
Mutation, Gene Flow, and Genetic Drift01:09

Mutation, Gene Flow, and Genetic Drift

59.0K
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).
59.0K
Hardy-Weinberg Principle01:49

Hardy-Weinberg Principle

72.7K
Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the gene pool of the population. The gene pool of a population is the sum of every allele of all genes within that population and has some degree of variation. Genetic variation is typically expressed as a relative frequency, which is the percentage of the total population that has a given allele, genotype or phenotype.
72.7K
Modern Molecular Taxonomy01:29

Modern Molecular Taxonomy

74
Advancements in molecular biology have revolutionized the identification and characterization of bacteria, with multiple methods leveraging DNA sequencing for enhanced precision. As sequencing technologies improve and costs decline, these approaches are increasingly used in clinical, environmental, and evolutionary studies.Multilocus Sequence Typing (MLST) examines several housekeeping genes, essential chromosomal genes encoding cellular functions, to distinguish strains. Approximately...
74
Evolutionary Relationships through Genome Comparisons02:54

Evolutionary Relationships through Genome Comparisons

6.1K
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...
6.1K
Genetic Variation01:25

Genetic Variation

348
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles,...
348

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Exploring likelihood ratios assigned for siblings of the true mixture contributor as an alternate contributor.

Journal of forensic sciences·2022
Same author

A comparison of likelihood ratios obtained from EuroForMix and STRmix™.

Journal of forensic sciences·2021
See all related articles

Related Experiment Video

Updated: Aug 13, 2025

Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry
05:53

Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry

Published on: June 21, 2018

10.2K

Evaluating DNA Mixtures with Contributors from Different Populations Using Probabilistic Genotyping.

Maarten Kruijver1, Hannah Kelly1, Jo-Anne Bright1

  • 1Institute of Environmental Science and Research, Auckland 1142, New Zealand.

Genes
|January 21, 2023
PubMed
Summary

Evaluating DNA evidence with multiple populations requires careful consideration. New methods using probabilistic genotyping and weighted likelihoods offer more accurate and conservative results for mixed or low-level DNA samples, especially when population stratification is accounted for.

Keywords:
DNA mixtureslikelihood ratiopopulation stratificationprobabilistic genotyping

More Related Videos

Detection of Rare Genomic Variants from Pooled Sequencing Using SPLINTER
14:06

Detection of Rare Genomic Variants from Pooled Sequencing Using SPLINTER

Published on: June 23, 2012

15.3K
Infinium Assay for Large-scale SNP Genotyping Applications
13:33

Infinium Assay for Large-scale SNP Genotyping Applications

Published on: November 19, 2013

39.1K

Related Experiment Videos

Last Updated: Aug 13, 2025

Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry
05:53

Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry

Published on: June 21, 2018

10.2K
Detection of Rare Genomic Variants from Pooled Sequencing Using SPLINTER
14:06

Detection of Rare Genomic Variants from Pooled Sequencing Using SPLINTER

Published on: June 23, 2012

15.3K
Infinium Assay for Large-scale SNP Genotyping Applications
13:33

Infinium Assay for Large-scale SNP Genotyping Applications

Published on: November 19, 2013

39.1K

Area of Science:

  • Forensic Science
  • Population Genetics
  • Statistical Genetics

Background:

  • Evaluating DNA profiling evidence commonly uses likelihood ratios based on allele frequencies from a single relevant population.
  • When multiple populations might be relevant, choosing an appropriate reference population or method is crucial.
  • Previous methods for two-person mixtures suggested using the Person of Interest’s population with a θ value of 3% for conservative estimates.

Purpose of the Study:

  • To develop and evaluate a method for DNA evidence evaluation using probabilistic genotyping for samples with contributors from different ethnic groups.
  • To investigate the behavior of likelihood ratios under different assumptions about donor origins and compare them to existing methods.
  • To assess the conservativeness of different approaches, including minimum likelihood ratios and population stratification methods, particularly for low-level and mixed DNA samples.

Main Methods:

  • Developed a probabilistic genotyping method that weights likelihoods across a prior distribution assigning sample donors to ethnic groups.
  • Utilized a simulation study to analyze the impact of assuming donors are from the same ethnic group versus considering all permutations.
  • Compared the proposed stratified likelihood ratio with the minimum likelihood ratio across populations.

Main Results:

  • Demonstrated that the common practice of using a minimum likelihood ratio across populations is not always conservative when FST=0.
  • Showed that population stratification methods can also be non-conservative in certain scenarios.
  • Found that when FST>0 is incorporated, as recommended, all compared approaches tend to be conservative on average.

Conclusions:

  • The choice of method for evaluating DNA evidence from potentially admixed populations significantly impacts likelihood ratio outcomes, especially for complex samples.
  • Existing methods like the minimum likelihood ratio may not always provide conservative estimates.
  • The proposed stratified likelihood ratio, particularly when accounting for population structure (FST>0), offers a more robust and generally conservative approach for forensic DNA analysis.